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Pagán E, López N, Sánchez A, Campillo R, Berdejo D, García-Gonzalo D, Pagán R. Growth fitness, virulence, and heat tolerance of Salmonella Typhimurium variants resistant to food preservation methods. Int J Food Microbiol 2024; 422:110810. [PMID: 38945050 DOI: 10.1016/j.ijfoodmicro.2024.110810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 06/05/2024] [Accepted: 06/23/2024] [Indexed: 07/02/2024]
Abstract
To study potential ramifications of antimicrobial resistance, we carried out adaptive laboratory evolution assays (ALE) to isolate three resistant variants (RVs) of Salmonella enterica Typhimurium, employing three different types of food preservation methods: 1) an emergent technology, plasma-activated water (PAW), leading to variant RV-PAW; a traditional method, heat, leading to variant RV-HT, and a natural antimicrobial compound, carvacrol, leading to variant RV-CAR. The variant resistant to plasma-activated water, RV-PAW, had mutations in rpoA and rpoD; it showed increased tolerance to heat in orange juice but ultimately did not pose a significant threat, as it exhibited a fitness cost at refrigeration temperature (8 °C), whereas its virulence against Caenorhabditis elegans decreased. The variant resistant to heat, RV-HT, had mutations in flhC, dnaJ: it exhibited a fitness cost at high growth temperatures (43 °C) and induced morphofunctional alterations in C. elegans. The variant resistant to carvacrol, RV-CAR, had mutations in sseG, flhA, wbaV, lon; this variant not only exhibited significantly higher thermotolerance in both laboratory media and food models but also effectively increased its growth fitness at refrigeration temperatures while retaining its virulence, evidenced by the highest percentage of Smurf phenotype in C. elegans. To address these challenges, we applied a process combining thermal treatment with citral, with the aim of leveraging the sublethal damage caused in RVs by heat treatments in orange juice. This approach achieves enhanced microbial inactivation without having to escalate the intensity of the thermal treatment. The result was particularly encouraging in the case of RV-CAR, the most challenging strain, for which we improved lethality by up to 3 log10 inactivation cycles.
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Affiliation(s)
- Elisa Pagán
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - Noelia López
- CNTA, Centro Nacional de Tecnología y Seguridad Alimentaria, San Adrián, Spain
| | - Ana Sánchez
- CNTA, Centro Nacional de Tecnología y Seguridad Alimentaria, San Adrián, Spain
| | - Raúl Campillo
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - Daniel Berdejo
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - Diego García-Gonzalo
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - Rafael Pagán
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Zaragoza, Spain.
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Gavriil A, Giannenas I, Skandamis PN. A current insight into Salmonella's inducible acid resistance. Crit Rev Food Sci Nutr 2024:1-21. [PMID: 39014992 DOI: 10.1080/10408398.2024.2373387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Salmonella is a diverse and ubiquitous group of bacteria and a major zoonotic pathogen implicated in several foodborne disease outbreaks worldwide. With more than 2500 distinct serotypes, this pathogen has evolved to survive in a wide spectrum of environments and across multiple hosts. The primary and most common source of transmission is through contaminated food or water. Although the main sources have been primarily linked to animal-related food products, outbreaks due to the consumption of contaminated plant-related food products have increased in the last few years. The perceived ability of Salmonella to trigger defensive mechanisms following pre-exposure to sublethal acid conditions, namely acid adaptation, has renewed a decade-long attention. The impact of acid adaptation on the subsequent resistance against lethal factors of the same or multiple stresses has been underscored by multiple studies. Α plethora of studies have been published, aiming to outline the factors that- alone or in combination- can impact this phenomenon and to unravel the complex networking mechanisms underlying its induction. This review aims to provide a current and updated insight into the factors and mechanisms that rule this phenomenon.
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Affiliation(s)
- Alkmini Gavriil
- Department of Natural Resources Management and Agricultural Engineering, Agricultural University of Athens, Athens, Greece
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Ilias Giannenas
- School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Panagiotis N Skandamis
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
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Yuan H, Xun H, Wang J, Wang J, Yao X, Tang F. Integrated Metabolomic and Transcriptomic Analysis Reveals the Underlying Antibacterial Mechanisms of the Phytonutrient Quercetin-Induced Fatty Acids Alteration in Staphylococcus aureus ATCC 27217. Molecules 2024; 29:2266. [PMID: 38792126 PMCID: PMC11123838 DOI: 10.3390/molecules29102266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
The utilization of natural products in food preservation represents a promising strategy for the dual benefits of controlling foodborne pathogens and enhancing the nutritional properties of foods. Among the phytonutrients, flavonoids have been shown to exert antibacterial effects by disrupting bacterial cell membrane functionality; however, the underlying molecular mechanisms remain elusive. In this study, we investigated the effect of quercetin on the cell membrane permeability of Staphylococcus aureus ATCC 27217. A combined metabolomic and transcriptomic approach was adopted to examine the regulatory mechanism of quercetin with respect to the fatty acid composition and associated genes. Kinetic analysis and molecular docking simulations were conducted to assess quercetin's inhibition of β-ketoacyl-acyl carrier protein reductase (FabG), a potential target in the bacterial fatty acid biosynthesis pathway. Metabolomic and transcriptomic results showed that quercetin increased the ratio of unsaturated to saturated fatty acids and the levels of membrane phospholipids. The bacteria reacted to quercetin-induced stress by attempting to enhance fatty acid biosynthesis; however, quercetin directly inhibited FabG activity, thereby disrupting bacterial fatty acid biosynthesis. These findings provide new insights into the mechanism of quercetin's effects on bacterial cell membranes and suggest potential applications for quercetin in bacterial inhibition.
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Affiliation(s)
| | | | | | | | | | - Feng Tang
- Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo & Rattan Science and Technology, International Centre for Bamboo and Rattan, Beijing 100102, China; (H.Y.); (H.X.); (J.W.); (J.W.); (X.Y.)
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Wang X, Zheng J, Luo L, Hong Y, Li X, Zhu Y, Wu Y, Bai L. Thermal inactivation kinetics of Listeria monocytogenes in milk under isothermal and dynamic conditions. Food Res Int 2024; 179:114010. [PMID: 38342535 DOI: 10.1016/j.foodres.2024.114010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 02/13/2024]
Abstract
Thermal processing is a widely used method to ensure the microbiological safety of milk. Predictive microbiology plays a crucial role in quantifying microbial growth and decline, providing valuable guidance on the design and optimization of food processing operations. This study aimed to investigate the thermal inactivation kinetics of Listeria monocytogenes in milk under both isothermal and dynamic conditions. The thermal inactivation of L. monocytogenes was conducted under isothermal and non-isothermal conditions in sterilized and pasteurized milk, with and without background microbiota, respectively. Furthermore, a secondary model was developed between the shoulder effect and temperature, which was then integrated into the dynamic model. The results showed that L. monocytogenes grown in Tryptic Soy Yeast Extract Broth (TSBYE) prior to thermal inactivation exhibited higher heat resistance compared to cells grown in sterilized milk at isothermal temperatures of 60.0, 62.5, and 65℃. Moreover, the presence of background microbiota in milk significantly enhanced the heat resistance of L. monocytogenes, as evidenced by the increased D-values from 1.13 min to 2.34 min, from 0.46 min to 0.53 min, and from 0.25 min to 0.34 min at 60.0, 62.5, and 65 °C, respectively, regardless of whether the background microbiota was inactivated after co-growth or co-inactivated with L. monocytogenes. For non-isothermal inactivation, the one-step dynamic model based on the log-linear with shoulder model effectively described the microbial inactivation curve and exhibited satisfactory model performance. The model developed contributes to improved risk assessment, enabling dairy processors to optimize thermal treatment and ensure microbiological safety.
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Affiliation(s)
- Xiang Wang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Jiaming Zheng
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Linyin Luo
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yi Hong
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Xiaofeng Li
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yuqi Zhu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yufan Wu
- Centre of Analysis and Test, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Li Bai
- Key Laboratory of Food Safety Risk Assessment, National Health Commission of the People's Republic of China, China National Center for Food Safety Risk Assessment, Beijing 100022, China.
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Sheet S, Sathishkumar Y, Acharya S, Lee YS. Exposure of Legionella pneumophila to low-shear modeled microgravity: impact on stress response, membrane lipid composition, pathogenicity to macrophages and interrelated genes expression. Arch Microbiol 2024; 206:87. [PMID: 38305908 DOI: 10.1007/s00203-023-03753-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 10/31/2023] [Accepted: 11/16/2023] [Indexed: 02/03/2024]
Abstract
Here, we studied the effect of low-shear modeled microgravity (LSMMG) on cross stress resistance (heat, acid, and oxidative), fatty acid content, and pathogenicity along with alteration in expression of stress-/virulence-associated genes in Legionella pneumophila. The stress resistance analysis result indicated that bacteria cultivated under LSMMG environments showed higher resistance with elevated D-values at 55 °C and in 1 mM of hydrogen peroxide (H2O2) conditions compared to normal gravity (NG)-grown bacteria. On the other hand, there was no significant difference in tolerance (p < 0.05) toward simulated gastric fluid (pH-2.5) acid conditions. In fatty acid analysis, our result showed that a total amount of saturated and cyclic fatty acids was increased in LSMMG-grown cells; as a consequence, they might possess low membrane fluidity. An upregulated expression level was noticed for stress-related genes (hslV, htrA, grpE, groL, htpG, clpB, clpX, dnaJ, dnaK, rpoH, rpoE, rpoS, kaiB, kaiC, lpp1114, ahpC1, ahpC2, ahpD, grlA, and gst) under LSMMG conditions. The reduced virulence (less intracellular bacteria and less % of induce apoptosis in RAW 264.7 macrophages) of L. pneumophila under LSMMG conditions may be because of downregulation related genes (dotA, dotB, dotC, dotD, dotG, dotH, dotL, dotM, dotN, icmK, icmB, icmS, icmT, icmW, ladC, rtxA, letA, rpoN, fleQ, fleR, and fliA). In the LSMMG group, the expression of inflammation-related factors, such as IL-1α, TNF-α, IL-6, and IL-8, was observed to be reduced in infected macrophages. Also, scanning electron microscopy (SEM) analysis showed less number of LSMMG-cultivated bacteria attached to the host macrophages compared to NG. Thus, our study provides understandings about the changes in lipid composition and different genes expression due to LSMMG conditions, which apparently influence the alterations of L. pneumophila' stress/virulence response.
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Affiliation(s)
- Sunirmal Sheet
- Department of Wood Science and Technology, College of Agriculture and Life Sciences, Jeonbuk National University, 567, Jeonju-si, Jeollabuk-do, Republic of Korea
| | | | - Satabdi Acharya
- Department of Biomedical Sciences and Institute for Medical Science, Jeonbuk National University Medical School, 567, Jeonju-si, Jeollabuk-do, Republic of Korea
| | - Yang Soo Lee
- Department of Wood Science and Technology, College of Agriculture and Life Sciences, Jeonbuk National University, 567, Jeonju-si, Jeollabuk-do, Republic of Korea.
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Tsai S, Tikekar RV. The effect of emulsifier type and oil inclusion on stress-related gene expression of Salmonella typhimurium in oil-in-water emulsion. J Food Sci 2024; 89:1211-1224. [PMID: 38224194 DOI: 10.1111/1750-3841.16908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/21/2023] [Accepted: 12/11/2023] [Indexed: 01/16/2024]
Abstract
Salmonella has been associated with numerous outbreaks from contaminated food products, including emulsions. Emulsions are influenced by emulsifier type and oil presence, which can have varying degrees of stress or protection on bacteria. Although our previous research has shown that emulsifier solutions, rather than emulsions, provide a protective effect on Salmonella typhimurium after thermal treatment, the underlying mechanism remains unclear. This study selected S. typhimurium as the model microorganism and utilized the same emulsifiers (Tween 20, Tween 80, Triton X-100) to create emulsifier solutions and emulsions with the same oil fraction (60% (v/v)) to examine their effect on the expression of nine selected genes (rpoE, rpoH, otsB, proV, fadA, fabA, dnaK, ibpA, ompC) associated with stress response. Specifically, the study observed variations in gene expression under normal and thermal stress at 55°C. After 20-h incubation, Triton X-100 emulsion caused an upregulation of stress-related genes, rpoE, otsB, and fabA, suggesting stressful environment. After thermal treatment, S. typhimurium in Triton X-100 solution showed a longer 5-log reduction time with increased proV and decreased fabA and ompC expression, suggesting enhanced thermal protection compared to its emulsion. Conversely, Tween 80 solution increased fabA and ompC expression, indicating greater membrane fluidity and passive diffusion, potentially reducing thermal resistance. However, according to the upregulation of ibpA, this effect was likely mitigated by the overproduction of heat shock proteins. Notably, Triton X-100 environments exhibited the most significant gene expression changes after heat treatment, whereas Tween 80 without oil was the most inhospitable for bacterial survival. These findings inform bacterial responses under various conditions, aiding food safety strategies.
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Affiliation(s)
- Shawn Tsai
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA
| | - Rohan V Tikekar
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA
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González-Tejedor GA, Garre A, Iguaz A, Wong-Zhang R, Fernández PS, Possas A. Dynamic Thermal Treatments in Green Coconut Water Induce Dynamic Stress Adaptation of Listeria innocua That Increases Its Thermal Resistance. Foods 2023; 12:4015. [PMID: 37959134 PMCID: PMC10650898 DOI: 10.3390/foods12214015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/23/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
The global coconut water market is projected to grow in the upcoming years, attributed to its numerous health benefits. However, due to its susceptibility to microbial contamination and the limitations of non-thermal decontamination methods, thermal treatments remain the primary approach to ensure the shelf-life stability and the microbiological safety of the product. In this study, the thermal inactivation of Listeria innocua, a Listeria monocytogenes surrogate, was evaluated in coconut water and in tryptone soy broth (TSB) under both isothermal (50-60 °C) and dynamic conditions (from 30 to 60 °C, with temperature increases of 0.5, 1 and 5 °C/min). Mathematical models were used to analyse the inactivation data. The Geeraerd model effectively described the thermal inactivation of L. innocua in both TSB and coconut water under isothermal conditions, with close agreement between experimental data and model fits. Parameter estimates and analysis revealed that acidified TSB is a suitable surrogate medium for studying the thermal inactivation of L. innocua in coconut water, despite minor differences observed in the shoulder length of inactivation curves, likely attributed to the media composition. The models fitted to the data obtained at isothermal conditions fail to predict L. innocua responses under dynamic conditions. This is attributed to the stress acclimation phenomenon that takes place under dynamic conditions, where bacterial cells adapt to initial sub-lethal treatment stages, leading to increased thermal resistance. Fitting the Bigelow model directly to dynamic data with fixed z-values reveals a three-fold increase in D-values with lower heating rates, supporting the role of stress acclimation. The findings of this study aid in designing pasteurization treatments targeting L. innocua in coconut water and enable the establishment of safe, mild heat treatments for refrigerated, high-quality coconut water.
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Affiliation(s)
- Gerardo A. González-Tejedor
- Sistema Nacional de Investigación (SNI), Senacyt, Ciudad de Panamá, Panama;
- Centro de Producción e Investigaciones Agroindustriales, Universidad Tecnológica de Panamá, Ciudad de Panamá, Panama;
| | - Alberto Garre
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain; (A.G.); (A.I.)
| | - Asunción Iguaz
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain; (A.G.); (A.I.)
| | - Ricardo Wong-Zhang
- Centro de Producción e Investigaciones Agroindustriales, Universidad Tecnológica de Panamá, Ciudad de Panamá, Panama;
| | - Pablo S. Fernández
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain; (A.G.); (A.I.)
| | - Arícia Possas
- Department of Food Science and Technology, UIC Zoonosis y Enfermedades Emergentes ENZOEM, CeiA3, Universidad de Córdoba, 14014 Córdoba, Spain
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Ko HI, Jeong CH, Park SJ, Kim SR, Eun JB, Kim TW. Influence of Isolation Temperature on Isolating Diverse Lactic Acid Bacteria from Kimchi and Cultural Characteristics of Psychrotrophs. J Microbiol Biotechnol 2023; 33:1066-1075. [PMID: 37280779 PMCID: PMC10468671 DOI: 10.4014/jmb.2303.03047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 06/08/2023]
Abstract
Kimchi is a traditional Korean fermented vegetable that is stored and fermented at low temperatures. However, kimchi lactic acid bacteria (LAB) are typically isolated under mesophilic conditions, which may be inappropriate for isolating the diverse LAB. Therefore, this study investigated the suitable conditions for isolating various LAB from kimchi. Here, LAB were isolated from four kimchi samples using MRS, PES, and LBS media and varying isolation temperatures (30, 20, 10, and 5°C). Then, MRS was selected as the suitable medium for LAB isolation. A comparison of culture-dependent and culture-independent approaches indicated that 5°C was not a suitable isolation temperature. Thus, the number and diversity of LAB were determined at 30, 20, and 10°C using 12 additional kimchi samples to elucidate the effect of isolation temperature. With the exception of two samples, most samples did not substantially differ in LAB number. However, Leuconostoc gelidum, Leuconostoc gasicomitatum, Leuconostoc inhae, Dellaglioa algida, Companilactobacillus kimchiensis, Leuconostoc miyukkimchii, Leuconostoc holzapfelii, and Leuconostoc carnosum were isolated only at 10 and 20°C. The growth curves of these isolates, except Leu. holzapfelii and Leu. carnosum, showed poor growth at 30°C. This confirmed their psychrotrophic characteristics. In Weissella koreensis, which was isolated at all isolation temperatures, there was a difference in the fatty acid composition of membranes between strains that could grow well at 30°C and those that could not. These findings can contribute to the isolation of more diverse psychrotrophic strains that were not well isolated under mesophilic temperatures.
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Affiliation(s)
- Hye In Ko
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Chang Hee Jeong
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea
- Honam National Institute of Biological Resources, Mokpo 587262, Republic of Korea
| | - Se-Jin Park
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - So-Rim Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Jong-Bang Eun
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Tae-Woon Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea
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Xu S, Chen H. The influence of almond's water activity and storage temperature on Salmonella survival and thermal resistance. Food Microbiol 2023; 113:104269. [PMID: 37098429 DOI: 10.1016/j.fm.2023.104269] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023]
Abstract
This study investigated the effects of inoculation method, water activity (aw), packaging method, and storage temperature and duration on the survival of Salmonella on almonds as well as their resistance to subsequent thermal treatments. Whole almond kernels were inoculated with a broth-based or agar-based growth Salmonella cocktail and conditioned to aw of 0.52, 0.43 or 0.27. Inoculated almonds with aw of 0.43 were treated with a previously validated treatment (4 h of dry heat at 73 °C) to determine the potential differences in heat resistance resulted from the two inoculation methods. The inoculation method did not significantly (P > 0.05) impact the thermal resistance of Salmonella. Inoculated almonds at aw of 0.52 and 0.27 were either vacuum packaged in moisture-impermeable mylar bags or non-vacuum packaged in moisture-permeable polyethylene bags before stored at 35, 22, 4, or -18 °C for up to 28 days. At selected storage intervals, almonds were measured for aw, analyzed for Salmonella population level, and subjected to dry heat treatment at 75 °C. Over the month-long storage of almonds, Salmonella populations remained almost unchanged (<0.2 log CFU/g) at 4 °C and -18 °C and declined slightly (<0.8 log CFU/g) at 22 °C and more substantially (1.6-2.0 log CFU/g) at 35 °C regardless of the inoculation method, packaging method, and almond aw. When stored at 35 °C, almonds with initial aw of 0.52 had significantly higher (P < 0.05) Salmonella reductions than those with initial aw of 0.27. Prior storage of almonds vacuum packaged in mylar bags at temperatures between -18 °C and 35 °C for 28 days affected their aw levels but did not significantly (P > 0.05) affect the subsequent thermal resistance of Salmonella at 75 °C regardless of almond aw and storage duration. Salmonella on almonds with higher aw was more sensitive to heat treatment than those with lower aw. To achieve >5 log CFU/g reductions of Salmonella, a dry heat treatment at 75 °C for 4 and 6 h was needed for almonds with initial aw of 0.52 and 0.27, respectively. When applying the dry heating technology for almond decontamination, the processing time needs to be determined based on initial aw of almonds regardless of storage condition or age of almonds within the current design frame.
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Kathiriya MR, Vekariya YV, Hati S. Understanding the Probiotic Bacterial Responses Against Various Stresses in Food Matrix and Gastrointestinal Tract: A Review. Probiotics Antimicrob Proteins 2023:10.1007/s12602-023-10104-3. [PMID: 37347421 DOI: 10.1007/s12602-023-10104-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2023] [Indexed: 06/23/2023]
Abstract
Probiotic bacteria are known to have ability to tolerate inhospitable conditions experienced during food preparation, food storage, and gastrointestinal tract of consumer. As probiotics are living cells, they are adversely affected by the harsh environment of the carrier matrix as well as low pH, bile salts, oxidative stress, osmotic pressure, and commensal microflora of the host. To overcome the unfavorable environments, many probiotics switch on the cell-mediated protection mechanisms, which helps them to survive, acclimatize and remain operational in the harsh circumstances. In this review, we provide comprehensive understanding on the different stresses experienced by the probiotic when added in carrier food as well as during human gastrointestinal tract transit. Under such situation how these health beneficial bacteria protect themselves by activation of several defense systems and get adapted to the lethal environments.
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Affiliation(s)
- Mital R Kathiriya
- Department of Dairy Microbiology, SMC College of Dairy Science, Kamdhenu University, Anand-388110, Gujarat, India
| | - Yogesh V Vekariya
- Department. of Dairy Engineering, SMC College of Dairy Science, Kamdhenu University, Anand-388110, Gujarat, India
| | - Subrota Hati
- Department of Dairy Microbiology, SMC College of Dairy Science, Kamdhenu University, Anand-388110, Gujarat, India.
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Chuang S, Ghoshal M, McLandsborough L. Efficacy of acidified water-in-oil emulsions against desiccated Salmonella as a function of acid carbon chain-length and membrane viscosity. Front Microbiol 2023; 14:1197473. [PMID: 37378296 PMCID: PMC10291884 DOI: 10.3389/fmicb.2023.1197473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/16/2023] [Indexed: 06/29/2023] Open
Abstract
Sanitizing low-moisture food (LMF) processing equipment is challenging due to the increased heat resistance of Salmonella spp. in low-water activity (aw) environments. Food-grade oils mixed with acetic acid have been shown effective against desiccated Salmonella. In this study, different hydrocarbon chain-length (Cn) organic acids were tested against desiccated Salmonella by using 1% v/v water-in-oil (W/O) emulsion as the delivery system for 200 mM acid. Fluorescence lifetime imaging microscopy (FLIM) was utilized with a BODIPY-based molecular rotor to evaluate membrane viscosity under environmental conditions such as desiccation and temperature elevation. Drying hydrated Salmonella cells to 75% equilibrium relative humidity (ERH) increased the membrane viscosity from 1,199 to 1,309 mPa·s (cP) at 22°C. Heating to 45°C decreased the membrane viscosity of hydrated cells from 1,199 to 1,082 mPa·s, and decreased that of the desiccated cells from 1,309 to 1,245 mPa·s. At both 22°C and 45°C, desiccated Salmonella was highly susceptible (>6.5 microbial log reduction (MLR) per stainless-steel coupon) to a 30-min treatment with the W/O emulsions formulated with short carbon chain acids (C1-3). By comparison, the emulsion formulations with longer carbon chain acids (C4-12) showed little to no MLR at 22°C, but achieved >6.5 MLR at 45°C. Based upon the decreased Salmonella membrane viscosity and the increased antimicrobial efficacy of C4-12 W/O emulsions with increasing temperature, we propose that heating can make the membrane more fluid which may allow the longer carbon chain acids (C4-12) to permeate or disrupt membrane structures.
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Affiliation(s)
- Shihyu Chuang
- Department of Food Science, University of Massachusetts, Amherst, MA, United States
| | - Mrinalini Ghoshal
- Department of Microbiology, University of Massachusetts, Amherst, MA, United States
| | - Lynne McLandsborough
- Department of Food Science, University of Massachusetts, Amherst, MA, United States
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12
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Ding Q, Ge C, Baker RC, Buchanan RL, Tikekar RV. Assessment of trans-cinnamaldehyde and eugenol assisted heat treatment against Salmonella Typhimurium in low moisture food components. Food Microbiol 2023; 112:104228. [PMID: 36906318 DOI: 10.1016/j.fm.2023.104228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/16/2022] [Accepted: 01/21/2023] [Indexed: 01/28/2023]
Abstract
Increased thermal resistance of Salmonella at low water activity (aw) is a significant food safety concern in low-moisture foods (LMFs). We evaluated whether trans-cinnamaldehyde (CA, 1000 ppm) and eugenol (EG, 1000 ppm), which can accelerate thermal inactivation of Salmonella Typhimurium in water, can show similar effect in bacteria adapted to low aw in different LMF components. Although CA and EG significantly accelerated thermal inactivation (55 °C) of S. Typhimurium in whey protein (WP), corn starch (CS) and peanut oil (PO) at 0.9 aw, such effect was not observed in bacteria adapted to lower aw (0.4). The matrix effect on bacterial thermal resistance was observed at 0.9 aw, which was ranked as WP > PO > CS. The effect of heat treatment with CA or EG on bacterial metabolic activity was also partially dependent on the food matrix. Bacteria adapted to lower aw had lower membrane fluidity and unsaturated to saturated fatty acids ratio, suggesting that bacteria at low aw can change its membrane composition to increase its rigidity, thus increasing resistance against the combined treatments. This study demonstrates the effect of aw and food components on the antimicrobials-assisted heat treatment in LMF and provides an insight into the resistance mechanism.
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Affiliation(s)
- Qiao Ding
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD, USA, 20742
| | - Chongtao Ge
- Mars Global Food Safety Center, Beijing, 101047, China
| | | | - Robert L Buchanan
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD, USA, 20742; Center for Food Safety and Security Systems, University of Maryland, College Park, MD, USA, 20742
| | - Rohan V Tikekar
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD, USA, 20742.
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13
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Moon S, Ham S, Jeong J, Ku H, Kim H, Lee C. Temperature Matters: Bacterial Response to Temperature Change. J Microbiol 2023; 61:343-357. [PMID: 37010795 DOI: 10.1007/s12275-023-00031-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/13/2023] [Accepted: 02/13/2023] [Indexed: 04/04/2023]
Abstract
Temperature is one of the most important factors in all living organisms for survival. Being a unicellular organism, bacterium requires sensitive sensing and defense mechanisms to tolerate changes in temperature. During a temperature shift, the structure and composition of various cellular molecules including nucleic acids, proteins, and membranes are affected. In addition, numerous genes are induced during heat or cold shocks to overcome the cellular stresses, which are known as heat- and cold-shock proteins. In this review, we describe the cellular phenomena that occur with temperature change and bacterial responses from a molecular perspective, mainly in Escherichia coli.
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Affiliation(s)
- Seongjoon Moon
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Soojeong Ham
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Juwon Jeong
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Heechan Ku
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Hyunhee Kim
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea.
| | - Changhan Lee
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea.
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14
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Ding Q, Ge C, Baker RC, Buchanan RL, Tikekar RV. The genetic response of Salmonella Typhimurium during trans-cinnamaldehyde assisted heat treatment and its correlation with bacterial resistance in different low moisture food components. Food Microbiol 2023; 113:104271. [PMID: 37098431 DOI: 10.1016/j.fm.2023.104271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 03/10/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023]
Abstract
Our previous study found that water activity (aw)- and matrix-dependent bacterial resistance wasdeveloped in Salmonella Typhimurium during antimicrobial-assisted heat treatment in low moisture foods (LMFs) matrices. To better understand the molecular mechanism behind the observed bacterial resistance, gene expression analysis was conducted on S. Typhimurium adapted to different conditions with or without the trans-cinnamaldehyde (CA)-assisted heat treatment via quantitative polymerase chain reaction (qPCR). Expression profiles of nine stress-related genes were analyzed. The upregulation of rpoH and dnaK and downregulation of ompC were observed during bacterial adaptation in LMF matrices and the combined heat treatment, which likely contributed to the bacterial resistance during the combined treatment. Their expression profiles were partially consistent with the previously-observed effect of aw or matrix on bacterial resistance. The upregulation of rpoE, otsB, proV, and fadA was also observed during adaptation in LMF matrices and might contribute to desiccation resistance, but likely did not contribute to bacterial resistance during the combined heat treatment. The observed upregulation of fabA and downregulation of ibpA could not be directly linked to bacterial resistance to either desiccation or the combined heat treatment. The results may assist the development of more efficient processing methods against S. Typhimurium in LMFs.
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Affiliation(s)
- Qiao Ding
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD, USA, 20742
| | - Chongtao Ge
- Mars Global Food Safety Center, Beijing, 101047, China
| | | | - Robert L Buchanan
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD, USA, 20742; Center for Food Safety and Security Systems, University of Maryland, College Park, MD, USA, 20742
| | - Rohan V Tikekar
- Department of Nutrition and Food Science, University of Maryland, 112 Skinner Building, College Park, MD, USA, 20742.
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15
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Qiaoling Z, Lili M, Jinqi C, Ruoru Z, Jingjing E, Caiqing Y, Ruixue W, Junguo W. Effects of the repair treatment on improving the heat resistance of Lactiplantibacillus plantarum LIP-1. INNOV FOOD SCI EMERG 2022. [DOI: 10.1016/j.ifset.2022.103251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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16
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Repeated sub-inhibitory doses of cassia essential oil do not increase the tolerance pattern in Listeria monocytogenes cells. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.113681] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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17
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Yang H, Yang S, Xia X, Deng R, Gao H, Dong Y. Sensitive Detection of a Single-Nucleotide Polymorphism in Foodborne Pathogens Using CRISPR/Cas12a-Signaling ARMS-PCR. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:8451-8457. [PMID: 35767832 DOI: 10.1021/acs.jafc.2c03304] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Salmonella infection, particularly that caused by drug-resistant strain, has become a worldwide public health issue. Herein, we presented a CRISPR/Cas12a-signaling ARMS-PCR assay, termed cARMS, capable of sensitively detecting drug-resistant Salmonella enterica (S. enterica) involving single-nucleotide polymorphism (SNP). Owing to the dual-recognition processes, i.e., allele-specific primed polymerization and CRISPR/Cas12 binding, the cARMS assay yielded a high sensitivity for detecting SNP down to ∼0.5%. We used the cARMS assay to investigate the adaptation of SNP-involved drug-resistant S. enterica to salt stress. It was found that the mutants exhibited stronger adaptation to salt stress, indicating the potential risk of using high salt content as a sterilization strategy. The results verified the feasibility of the cARMS assay in controlling SNP-involved bacteria-associated biosafety.
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Affiliation(s)
- Hao Yang
- College of Biomass Science and Engineering, Healthy Food Evaluation Research Center, Sichuan University, Chengdu 610065, China
| | - Sen Yang
- College of Biomass Science and Engineering, Healthy Food Evaluation Research Center, Sichuan University, Chengdu 610065, China
| | - Xuhan Xia
- College of Biomass Science and Engineering, Healthy Food Evaluation Research Center, Sichuan University, Chengdu 610065, China
| | - Ruijie Deng
- College of Biomass Science and Engineering, Healthy Food Evaluation Research Center, Sichuan University, Chengdu 610065, China
| | - Hong Gao
- College of Biomass Science and Engineering, Healthy Food Evaluation Research Center, Sichuan University, Chengdu 610065, China
| | - Yi Dong
- College of Biomass Science and Engineering, Healthy Food Evaluation Research Center, Sichuan University, Chengdu 610065, China
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18
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Bhowmik BK, Kumar A, Gangaiah D. Transcriptome Analyses of Chicken Primary Macrophages Infected With Attenuated Salmonella Typhimurium Mutants. Front Microbiol 2022; 13:857378. [PMID: 35591991 PMCID: PMC9111174 DOI: 10.3389/fmicb.2022.857378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Salmonella enterica is one of the most common foodborne illnesses in the United States and worldwide, with nearly one-third of the cases attributed to contaminated eggs and poultry products. Vaccination has proven to be an effective strategy to reduce Salmonella load in poultry. The Salmonella Typhimurium Δcrp-cya (MeganVac1) strain is the most commonly used vaccine in the United States; however, the mechanisms of virulence attenuation and host response to this vaccine strain are poorly understood. Here, we profiled the invasion and intracellular survival phenotypes of Δcrp-cya and its derivatives (lacking key genes required for intra-macrophage survival) in HD11 macrophages and the transcriptome response in primary chicken macrophages using RNA-seq. Compared to the parent strain UK1, all the mutant strains were highly defective in metabolizing carbon sources related to the TCA cycle and had greater doubling times in macrophage-simulating conditions. Compared to UK1, the majority of the mutants were attenuated for invasion and intra-macrophage survival. Compared to Δcrp-cya, while derivatives lacking phoPQ, ompR-envZ, feoABC and sifA were highly attenuated for invasion and intracellular survival within macrophages, derivatives lacking ssrAB, SPI13, SPI2, mgtRBC, sitABCD, sopF, sseJ and sspH2 showed increased ability to invade and survive within macrophages. Transcriptome analyses of macrophages infected with UK1, Δcrp-cya and its derivatives lacking phoPQ, sifA and sopF demonstrated that, compared to uninfected macrophages, 138, 148, 153, 155 and 142 genes were differentially expressed in these strains, respectively. Similar changes in gene expression were observed in macrophages infected with these strains; the upregulated genes belonged to innate immune response and host defense and the downregulated genes belonged to various metabolic pathways. Together, these data provide novel insights on the relative phenotypes and early response of macrophages to the vaccine strain and its derivatives. The Δcrp-cya derivatives could facilitate development of next-generation vaccines with improved safety.
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Affiliation(s)
| | - Arvind Kumar
- Discovery Bacteriology and Microbiome, Elanco Animal Health Inc., Greenfield, IN, United States
| | - Dharanesh Gangaiah
- Discovery Bacteriology and Microbiome, Elanco Animal Health Inc., Greenfield, IN, United States
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19
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Heat shock in Cronobacter sakazakii induces direct protection and cross-protection against simulated gastric fluid stress. Food Microbiol 2022; 103:103948. [DOI: 10.1016/j.fm.2021.103948] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 11/10/2021] [Accepted: 11/13/2021] [Indexed: 11/21/2022]
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20
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Kim SH, Jyung S, Kang DH. Comparative study of Salmonella Typhimurium biofilms and their resistance depending on cellulose secretion and maturation temperatures. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2021.112700] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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21
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Tchuenchieu A, Sado Kamdem S, Bevivino A, Etoa FX, Essia Ngang JJ. Development of a predictive model of the microbial inactivation of L. monocytogenes during low thermal treatment of fruit juices in combination with carvacrol as aroma compound. Curr Res Food Sci 2022; 5:374-381. [PMID: 35198997 PMCID: PMC8850550 DOI: 10.1016/j.crfs.2022.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 01/31/2022] [Accepted: 02/06/2022] [Indexed: 11/29/2022] Open
Abstract
Mild heat treatment of fruit juices in combination with natural aroma compounds has been reported as an alternative to conventional pasteurization to better preserve their nutritional value. However, its antimicrobial efficiency varies from one juice to another. This study aims at developing a secondary predictive model of microbial inactivation scale during such combined process. Carvacrol was used as aroma compound and acid-adapted L. monocytogenes as target microorganism. The inactivation kinetics of this bacteria were followed in simulated fruit juices using a Central Composite Design with pH (2-6), °Brix (0–24), temperature (55–65 °C), and carvacrol concentration (0–60 μL/L) as independent variables. Curves were fitted to the Weibull inactivation model, and data collected used to generate two predictive models of the inactivation scale parameter through multiple regression analysis following an empirical and a mechanistic (based on Gamma concept) approach. The best of the two models was then validated using real fruit (orange, pineapple, and watermelon) juices. The empirical model where only the four variables tested were considered showed a lower statistical performance compared to the mechanistic model where octanol-water partition coefficient (Ko/w) and vapour pressure (Vp) of carvacrol at the treatment temperature were integrated (R2 0.6 and 0.9; Accuracy factor 1.5 and 1.3; Sum of Squared Error 3.6 and 1.1, respectively). No significant difference was observed between inactivation scale values obtained with real juices and the predicted values calculated using this mechanistic model. The Ko/w and Vp of the aroma compound used are key parameters that determine the efficiency of the above-described combined treatment. pH and Brix of fruit juices determine L. monocytogenes mild heat inactivation Carvacrol supplementation enhances mild heat tolerance of Listeria monocytogenes This carvacrol effect is determined by its partition coefficient and vapour pressure Consideration of these two physicochemical parameters increases model prediction.
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Affiliation(s)
- Alex Tchuenchieu
- Centre for Food and Nutrition Research, IMPM, PO Box 6163, Yaoundé, Cameroon
- Department of Microbiology, University of Yaoundé I, PO Box 812, Yaoundé, Cameroon
- Biotechnologies and Agroindustry Division, Department for Sustainability, ENEA, Italy
- Food Evolution Research Laboratory, University of Johannesburg, South Africa
- Corresponding author. Centre for Food and Nutrition Research, IMPM, PO Box 6163, Yaoundé, Cameroon.;
| | - Sylvain Sado Kamdem
- Department of Microbiology, University of Yaoundé I, PO Box 812, Yaoundé, Cameroon
| | - Annamaria Bevivino
- Biotechnologies and Agroindustry Division, Department for Sustainability, ENEA, Italy
| | - Francois-Xavier Etoa
- Department of Microbiology, University of Yaoundé I, PO Box 812, Yaoundé, Cameroon
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22
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Jiao S, Zhang H, Liao M, Hayouka Z, Jing P. Investigation of the potential direct and cross protection effects of sublethal injured Salmonella Typhimurium induced by radio frequency heating stress. Food Res Int 2021; 150:110789. [PMID: 34865804 DOI: 10.1016/j.foodres.2021.110789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 09/22/2021] [Accepted: 10/24/2021] [Indexed: 10/20/2022]
Abstract
Many studies demonstrated that radio frequency (RF) was an effective pasteurization method for low-moisture foods (LMFs), and our previous study confirmed RF heating stress generated sublethal injured cells (SICs) of Salmonella enterica serovar Typhimurium (S. Typhimurium) in red pepper powder with initial aw ≥ 0.53. So this study investigated the potential direct protection and cross protection effects of the SICs of S. Typhimurium to multiple stresses, and analyzed fatty acid composition and cell morphology. Results showed that the SICs were repaired after incubating for 5 h, and there were no obvious direct and cross protection effects by exposing to different external stresses (heat, 15% ethanol, pH 3.0 acid buffer solution, 10% salt). According to the fatty acid composition analysis, no significant difference (p > 0.05) between the ratio of unsaturated to saturated fatty acids (UFA/SFA) was observed for SICs of S. Typhimurium and control cells, indicating the same membrane fluidity which can support the experimental results. This study investigated and confirmed there are no direct and cross protection effects for the SICs of S. Typhimurium induced by RF heating stress, and it would be helpful for deeply understand the response of pathogens under RF heating stress.
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Affiliation(s)
- Shunshan Jiao
- SJTU-OSU Innovation Center for Environmental Sustainability and Food Control, Shanghai Food Safety and Engineering Technology Research Center, Key Laboratory of Urban Agriculture, Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Hangjin Zhang
- SJTU-OSU Innovation Center for Environmental Sustainability and Food Control, Shanghai Food Safety and Engineering Technology Research Center, Key Laboratory of Urban Agriculture, Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Meiji Liao
- SJTU-OSU Innovation Center for Environmental Sustainability and Food Control, Shanghai Food Safety and Engineering Technology Research Center, Key Laboratory of Urban Agriculture, Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Zvi Hayouka
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Pu Jing
- SJTU-OSU Innovation Center for Environmental Sustainability and Food Control, Shanghai Food Safety and Engineering Technology Research Center, Key Laboratory of Urban Agriculture, Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China.
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23
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Mladenović KG, Grujović MŽ, Kiš M, Furmeg S, Tkalec VJ, Stefanović OD, Kocić-Tanackov SD. Enterobacteriaceae in food safety with an emphasis on raw milk and meat. Appl Microbiol Biotechnol 2021; 105:8615-8627. [PMID: 34731280 DOI: 10.1007/s00253-021-11655-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 10/19/2022]
Abstract
There has been a growing interest in traditional dairy (such as raw milk cheeses) and meat products, in recent years. However, these products are suitable and nutrient medium and may be easily contaminated by microorganisms such as Enterobacteriaceae. Enterobacteriaceae are considered to be the indicator bacteria for microbiological quality of food and hygiene status of a production process. Additionally, the food contaminated by Enterobacteriaceae poses a microbiological risk for consumers. In fact, the contamination of raw milk and meat by Enterobacteriaceae amid manufacturing may easily occur from various environmental sources, and this group of bacteria is frequently detected in dairy and meat products. Therefore, monitoring the microbiological quality of the used raw material and maintaining high standards of hygiene in the production process are mandatory for a high quality of traditional products and the safety of the potential consumers. The goal of this review is to present the most recent survey on Enterobacteriaceae growth, number, and distribution in raw milk cheeses and meat, as well as to discuss the sources of contamination and methods of control. KEY POINTS: • Enterobacteriaceae: role and importance in milk and meat products, EU legal regulations • Dynamics, distribution, and survival of Enterobacteriaceae in milk and meat • Mechanisms of control of Enterobacteriaceae in dairy products.
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Affiliation(s)
- K G Mladenović
- Faculty of Science, Department of Biology and Ecology, University of Kragujevac, Radoja Domanovića 12, 34000, Kragujevac, Republic of Serbia. .,Institute for Information Technologies, Department of Science, University of Kragujevac, JovanaCvijica Bb, 34000, Kragujevac, Republic of Serbia.
| | - M Ž Grujović
- Faculty of Science, Department of Biology and Ecology, University of Kragujevac, Radoja Domanovića 12, 34000, Kragujevac, Republic of Serbia.,Institute for Information Technologies, Department of Science, University of Kragujevac, JovanaCvijica Bb, 34000, Kragujevac, Republic of Serbia
| | - M Kiš
- Laboratory for Food and Feed Microbiology, Croatian Veterinary Institute, Veterinary Institute Križevci, Zakmardijeva 10, 48260, Križevci, Croatia
| | - S Furmeg
- Laboratory for Food and Feed Microbiology, Croatian Veterinary Institute, Veterinary Institute Križevci, Zakmardijeva 10, 48260, Križevci, Croatia
| | - V Jaki Tkalec
- Laboratory for Food and Feed Microbiology, Croatian Veterinary Institute, Veterinary Institute Križevci, Zakmardijeva 10, 48260, Križevci, Croatia
| | - O D Stefanović
- Faculty of Science, Department of Biology and Ecology, University of Kragujevac, Radoja Domanovića 12, 34000, Kragujevac, Republic of Serbia
| | - S D Kocić-Tanackov
- Faculty of Technology, University in Novi Sad, Cara Lazara 1, 21000, Novi Sad, Republic of Serbia
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24
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Cyclopropane Fatty Acids are Important for Salmonella enterica serovar Typhimurium Virulence. Infect Immun 2021; 90:e0047921. [PMID: 34662213 DOI: 10.1128/iai.00479-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A variety of eubacteria, plants and protozoa can modify membrane lipids by cyclopropanation, which is reported to modulate membrane permeability and fluidity. The ability to cyclopropanate membrane lipids has been associated with resistance to oxidative stress in Mycobacterium tuberculosis, organic solvent stress in Escherichia coli, and acid stress in E. coli and Salmonella. In bacteria, the cfa gene encoding cyclopropane fatty acid (CFA) synthase is induced during the stationary phase of growth. In the present study we constructed a cfa mutant of Salmonella enterica serovar Typhimurium 14028s (S. Typhimurium) and determined the contribution of CFA-modified lipids to stress resistance and virulence in mice. Cyclopropane fatty acid content was quantified in wild-type and cfa mutant S. Typhimurium. CFA levels in a cfa mutant were greatly reduced compared to wild-type, indicating that CFA synthase is the major enzyme responsible for cyclopropane modification of lipids in Salmonella. S. Typhimurium cfa mutants were more sensitive to extreme acid pH, the protonophore CCCP, and hydrogen peroxide, compared to wild-type. In addition, cfa mutants exhibited reduced viability in murine macrophages and could be rescued by addition of the NADPH phagocyte oxidase inhibitor diphenyleneiodonium (DPI) chloride. S. Typhimurium lacking cfa was also attenuated for virulence in mice. These observations indicate that CFA modification of lipids makes an important contribution to Salmonella virulence.
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25
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E J, Chen J, Chen Z, Ma R, Zhang J, Yao C, Wang R, Zhang Q, Yang Y, Li J, Wang J. Effects of different initial pH values on freeze-drying resistance of Lactiplantibacillus plantarum LIP-1 based on transcriptomics and proteomics. Food Res Int 2021; 149:110694. [PMID: 34600689 DOI: 10.1016/j.foodres.2021.110694] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 08/15/2021] [Accepted: 08/31/2021] [Indexed: 12/21/2022]
Abstract
The growth and the resistance to adverse environments of lactic acid bacteria would be affected by adjusting the initial pH of the medium. In order to explore the effect of changing the initial pH of culture medium on the freeze-drying survival rate of the Lactiplantibacillus plantarum LIP-1, the effect of initial pH on cell membrane fatty acid composition and key enzyme activity were mainly determined, and the internal mechanism was studied by transcriptomics and proteomics methods. We found that compared with initial pH 7.4 group, initial pH 6.8 group could improve the freeze-drying survival rate of the L. plantarum LIP-1. It was possibly due to the lactate dehydrogenase (LDH) was upregulated in the initial pH6.8 group, which led to a rapid decrease in culture pH. To reduce the inhibitory effect of long-term acid environment on growth, the strain upregulated the expression of fatty acid synthesis-related genes and proteins, promoted the relative content of cyclopropane and unsaturated fatty acids, improved integrity of the cell membranes. The adjustment of fatty acid composition maintained the integrity of the cell membrane in a freeze-drying environment to improve the freeze-drying survival rate of the initial pH6.8 group. In addition, the long-term acid environment stimulated a cross-stress tolerance mechanism that significantly upregulated the expression of a cold stress protein. The results indicated that the optimal initial pH of the medium could improve the ability of L. plantarum LIP-1 to resist freeze-drying.
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Affiliation(s)
- Jingjing E
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Jing Chen
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Zichao Chen
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Rongze Ma
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Jingya Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Caiqing Yao
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Ruixue Wang
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Qiaoling Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Ying Yang
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Jing Li
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
| | - Junguo Wang
- Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, PR China
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Zhang TZ, Liu LP, Ye L, Li WC, Xin B, Xie YY, Jia SR, Wang TF, Zhong C. The production of bacterial cellulose in Gluconacetobacter xylinus regulated by luxR overexpression of quorum sensing system. Appl Microbiol Biotechnol 2021; 105:7801-7811. [PMID: 34581846 DOI: 10.1007/s00253-021-11603-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/27/2021] [Accepted: 09/14/2021] [Indexed: 12/28/2022]
Abstract
Quorum sensing is a mechanism that facilitates cell-to-cell communication. Through signal molecular density for signal recognition, which leads to the regulation of some physiological and biochemical functions. Gluconacetobacter xylinus CGMCC 2955, which produces bacterial cellulose (BC), synthesizes the LuxR protein belonging to the LuxI/LuxR type QS system. Here, a luxR overexpression vector was transformed into G. xylinus CGMCC 2955. The overexpression of luxR increased the yield of BC by 15.6% after 16 days static culture and reduced the cell density by 15.5% after 120-h-agitated culture. The glucose was used up by G. xylinus-pMV24-luxR at 72-h-agitated fermentation, which 12 h earlier than the wild-type (WT). The total N-acylhomoserine lactones (AHL) content of the luxR-overexpressing strain and the WT strain attained 1367.9 ± 57.86 mg/L and 842.9 ± 54.22 mg/L, respectively. The C12-HSL and C14-HSL contents of G. xylinus-pMV24-luxR were 202 ± 21.66 mg/L and 409.6 ± 0.91 mg/L, which were significantly lower than that of WT. In contrast, C6-HSL showed opposite results. The difference of AHL content proved that overexpression of luxR improved the binding of AHL and showed preference for some specific AHL. The metabolic results demonstrated that upon glucose exhaustion, the consumption of gluconic acid was promoted by luxR overexpression, and the content of D- ( +)-trehalose, an antiretrograde metabolite, increased significantly. KEY POINTS: • The overexpression of luxR increased the yield of bacterial cellulose • The content of signal molecules was significantly different • Differential metabolites were involved in multiple metabolic pathways.
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Affiliation(s)
- Tian-Zhen Zhang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, People's Republic of China
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Ling-Pu Liu
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Li Ye
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Wen-Chao Li
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Bo Xin
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Yan-Yan Xie
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Shi-Ru Jia
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China
| | - Teng-Fei Wang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, People's Republic of China.
| | - Cheng Zhong
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457, People's Republic of China.
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Schütz V, Frindte K, Cui J, Zhang P, Hacquard S, Schulze-Lefert P, Knief C, Schulz M, Dörmann P. Differential Impact of Plant Secondary Metabolites on the Soil Microbiota. Front Microbiol 2021; 12:666010. [PMID: 34122379 PMCID: PMC8195599 DOI: 10.3389/fmicb.2021.666010] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 04/27/2021] [Indexed: 11/28/2022] Open
Abstract
Plant metabolites can shape the microbial community composition in the soil. Two indole metabolites, benzoxazolinone (BOA) and gramine, produced by different Gramineae species, and quercetin, a flavonoid synthesized by many dicot species, were studied for their impacts on the community structure of field soil bacteria. The three plant metabolites were directly added to agricultural soil over a period of 28 days. Alterations in bacterial composition were monitored by next generation sequencing of 16S rRNA gene PCR products and phospholipid fatty acid analysis. Treatment of the soil with the plant metabolites altered the community composition from phylum to amplicon sequence variant (ASV) level. Alpha diversity was significantly reduced by BOA or quercetin, but not by gramine. BOA treatment caused a decrease of the relative abundance of 11 ASVs, while only 10 ASVs were increased. Gramine or quercetin treatment resulted in the increase in relative abundance of many more ASVs (33 or 38, respectively), most of them belonging to the Proteobacteria. Isolation and characterization of cultivable bacteria indicated an enrichment in Pseudarthrobacter or Pseudomonas strains under BOA/quercetin or BOA/gramine treatments, respectively. Therefore, the effects of the treatments on soil bacteria were characteristic for each metabolite, with BOA exerting a predominantly inhibitory effect, with only few genera being able to proliferate, while gramine and quercetin caused the proliferation of many potentially beneficial strains. As a consequence, BOA or gramine biosynthesis, which have evolved in different barley species, is accompanied with the association of distinct bacterial communities in the soil, presumably after mutual adaptation during evolution.
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Affiliation(s)
- Vadim Schütz
- Institute of Molecular Physiology and Biotechnology of Plants, Bonn, Germany
| | - Katharina Frindte
- Institute of Crop Science and Resource Conservation, Molecular Biology of the Rhizosphere, Bonn, Germany
| | - Jiaxin Cui
- Institute of Molecular Physiology and Biotechnology of Plants, Bonn, Germany
| | - Pengfan Zhang
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | | | | | - Claudia Knief
- Institute of Crop Science and Resource Conservation, Molecular Biology of the Rhizosphere, Bonn, Germany
| | - Margot Schulz
- Institute of Molecular Physiology and Biotechnology of Plants, Bonn, Germany
| | - Peter Dörmann
- Institute of Molecular Physiology and Biotechnology of Plants, Bonn, Germany
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Mendoza-Mejía BD, Medina-Aparicio L, Serrano-Fujarte I, Vázquez A, Calva E, Hernández-Lucas I. Salmonella enterica serovar Typhi genomic regions involved in low pH resistance and in invasion and replication in human macrophages. ANN MICROBIOL 2021. [DOI: 10.1186/s13213-021-01629-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Purpose
Salmonella enterica serovar Typhi, the etiological agent of typhoid fever, causes a systemic life-threatening disease. To carry out a successful infection process, this bacterium needs to survive alkaline and acid pH conditions presented in the mouth, stomach, small intestine, and gallbladder. Therefore, in this work, a genetic screening to identify S. Typhi genes involved in acid and circumneutral pH resistance was performed.
Methods
A collection of S. Typhi mutants deleted of fragments ranging from 6 to 80 kb were obtained by the Datsenko and Wanner method. Bacterial growth rate assays of each mutant were performed to identify S. Typhi genes involved in circumneutral and acid pH resistance. S. Typhi mutants deficient to growth at specific pH were evaluated in their capacity to invade and replicate in phagocytic cells.
Results
In this work, it is reported that S. Typhi ∆F4 (pH 4.5), S. Typhi ∆F44 (pH 4.5, 5.5, and 6.5), and S. Typhi ∆F73 (pH 4.5, 5.5, 6.5, and 7.5) were deficient to grow in the pH indicated. These three mutant strains were also affected in their ability to invade and replicate in human macrophages.
Conclusions
S. Typhi contains defined genomic regions that influence the survival at specific pH values, as well as the invasion and replication inside human cells. Thus, this genetic information probably allows the bacteria to survive in different human compartments for an efficient infection cycle.
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Wu RA, Yuk HG, Liu D, Ding T. Recent advances in understanding the effect of acid-adaptation on the cross-protection to food-related stress of common foodborne pathogens. Crit Rev Food Sci Nutr 2021; 62:7336-7353. [PMID: 33905268 DOI: 10.1080/10408398.2021.1913570] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Acid stress is one of the most common stresses that foodborne pathogens encounter. It could occur naturally in foods as a by-product of anaerobic respiration (fermentation), or with the addition of acids. However, foodborne pathogens have managed to survive to acid conditions and consequently develop cross-protection to subsequent stresses, challenging the efficacy of hurdle technologies. Here, we cover the studies describing the cross-protection response following acid-adaptation, and the possible molecular mechanisms for cross-protection. The current and future prospective of this research topic with the knowledge gaps in the literature are also discussed. Exposure to acid conditions (pH 3.5 - 5.5) could induce cross-protection for foodborne pathogens against subsequent stress or multiple stresses such as heat, cold, osmosis, antibiotic, disinfectant, and non-thermal technology. So far, the known molecular mechanisms that might be involved in cross-protection include sigma factors, glutamate decarboxylase (GAD) system, protection or repair of molecules, and alteration of cell membrane. Cross-protection could pose a serious threat to food safety, as many hurdle technologies are believed to be effective in controlling foodborne pathogens. Thus, the exact mechanisms underlying cross-protection in a diversity of bacterial species, stress conditions, and food matrixes should be further studied to reduce potential food safety risks. HighlightsFoodborne pathogens have managed to survive to acid stress, which may provide protection to subsequent stresses, known as cross-protection.Acid-stress may induce cross-protection to many stresses such as heat, cold, osmotic, antibiotic, disinfectant, and non-thermal technology stress.At the molecular level, foodborne pathogens use different cross-protection mechanisms, which may correlate with each other.
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Affiliation(s)
- Ricardo A Wu
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, China
| | - Hyun-Gyun Yuk
- Department of Food Science and Technology, Korea National University of Transportation, Chungbuk, Republic of Korea
| | - Donghong Liu
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, China
| | - Tian Ding
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, China
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Molecular and Physiological Adaptations to Low Temperature in Thioalkalivibrio Strains Isolated from Soda Lakes with Different Temperature Regimes. mSystems 2021; 6:6/2/e01202-20. [PMID: 33906913 PMCID: PMC8092127 DOI: 10.1128/msystems.01202-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genus Thioalkalivibrio comprises sulfur-oxidizing bacteria thriving in soda lakes at high pH and salinity. Depending on the geographical location and the season, these lakes can strongly vary in temperature. To obtain a comprehensive understanding of the molecular and physiological adaptations to low temperature, we compared the responses of two Thioalkalivibrio strains to low (10°C) and high (30°C) temperatures. For this, the strains were grown under controlled conditions in chemostats and analyzed for their gene expression (RNA sequencing [RNA-Seq]), membrane lipid composition, and glycine betaine content. The strain Thioalkalivibrio versutus AL2T originated from a soda lake in southeast Siberia that is exposed to strong seasonal temperature differences, including freezing winters, whereas Thioalkalivibrio nitratis ALJ2 was isolated from an East African Rift Valley soda lake with a constant warm temperature the year round. The strain AL2T grew faster than ALJ2 at 10°C, likely due to its 3-fold-higher concentration of the osmolyte glycine betaine. Moreover, significant changes in the membrane lipid composition were observed for both strains, leading to an increase in their unsaturated fatty acid content via the Fab pathway to avoid membrane stiffness. Genes for the transcriptional and translational machinery, as well as for counteracting cold-induced hampering of nucleotides and proteins, were upregulated. Oxidative stress was reduced by induction of vitamin B12 biosynthesis genes, and growth at 10°C provoked downregulation of genes involved in the second half of the sulfur oxidation pathway. Genes for intracellular signal transduction were differentially expressed, and interestingly, AL2T upregulated flagellin expression, whereas ALJ2 downregulated it. IMPORTANCE In addition to their haloalkaline conditions, soda lakes can also harbor a variety of other extreme parameters, to which their microbial communities need to adapt. However, for most of these supplementary stressors, it is not well known yet how haloalkaliphiles adapt and resist. Here, we studied the strategy for adaptation to low temperature in the haloalkaliphilic genus Thioalkalivibrio by using two strains isolated from soda lakes with different temperature regimes. Even though the strains showed a strong difference in growth rate at 10°C, they exhibited similar molecular and physiological adaptation responses. We hypothesize that they take advantage of resistance mechanisms against other stressors commonly found in soda lakes, which are therefore maintained in the bacteria living in the absence of low-temperature pressure. A major difference, however, was detected for their glycine betaine content at 10°C, highlighting the power of this osmolyte to also act as a key compound in cryoprotection. Author Video: An author video summary of this article is available.
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de Souza TR, Gonçalves MC, do Vale LA, Vitorino LC, Piccoli RH. Homologous and Heterologous Adaptation and Thermochemical Inactivation of Staphylococcus aureus with Exposure to Cinnamaldehyde. J Food Prot 2021; 84:579-586. [PMID: 33180940 DOI: 10.4315/jfp-20-336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/09/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Staphylococcus aureus causes food intoxication and can become resistant to a large number of antibacterial drugs. Thus, there is a growing interest in understanding the mechanisms involved in the adaptation of bacterial cells to environmental stresses or to antimicrobial agents. In this context, we evaluated the cinnamaldehyde (CIN) MBC for two contaminating food strains of S. aureus (GL 5674 and GL 8702) and tested the hypothesis that exposure of these strains to sublethal CIN concentrations and pH values could increase their resistance to this antimicrobial agent, to acid stress, and also to stress at high temperatures. Thus, the ability of the strains to adapt to CIN and acid stress was evaluated, as well as the cross-adaptation between acid stress and CIN. Strains GL 5674 and GL 8702 of S. aureus are sensitive to CIN in MBCs of 0.25 and 0.5% respectively, proving the antibacterial potential of this compound, but we proved the hypothesis of homologous adaptation to CIN. The strains grew in concentrations higher than the MBC after being previously exposed to sublethal concentrations of CIN. We also observed heterologous adaptation of the strains, which after exposure to the minimum pH for growth, were able to grow in concentrations of CIN greater than the MBC. GL 5674 showed greater adaptive plasticity, considerably reducing its minimum inhibitory pH and increasing its MBC after adaptation. Our results show a positive effect of adaptation to CIN on the resistance of S. aureus (P < 0.0001) to CIN at a temperature of 37°C. However, in the absence of adaptation, the presence of CIN in S. aureus cultures maintained at 37°C showed an efficient bactericidal effect associated with increased exposure time. Our results call attention to the conscious use of CIN as an antimicrobial agent and present the possibility of using CIN, in association with a temperature of 37°C and an exposure time of 35 min, as a promising measure for the elimination of pathogenic strains. HIGHLIGHTS
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Affiliation(s)
- Tenille Ribeiro de Souza
- Agricultural Microbiology, Department of Biology, Federal University of Lavras, Central Avenue, 37200-000 Lavras, Minas Gerais, Brazil
| | - Michelle Carlota Gonçalves
- Agricultural Microbiology, Department of Biology, Federal University of Lavras, Central Avenue, 37200-000 Lavras, Minas Gerais, Brazil
| | - Letícia Andrade do Vale
- Department of Food Sciences, Federal University of Lavras, Central Avenue, 37200-000 Lavras, Minas Gerais, Brazil
| | - Luciana Cristina Vitorino
- Laboratory of Agricultural Microbiology, Goiano Federal Institute-Campus Rio Verde, Highway Sul Goiana, Km 01, 75901-970 Rio Verde, Goiás, Brazil (ORCID: https://orcid.org/0000-0001-7271-9573 [L.C.V.])
| | - Roberta Hilsdorf Piccoli
- Department of Food Sciences, Federal University of Lavras, Central Avenue, 37200-000 Lavras, Minas Gerais, Brazil
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Zhang RR, Shi YG, Gu Q, Fang M, Chen YW, Fang S, Dang YL, Chen JS. Antimicrobial effect and mechanism of non-antibiotic alkyl gallates against Pseudomonas fluorescens on the surface of Russian sturgeon (Acipenser gueldenstaedti). Int J Food Microbiol 2021; 342:109093. [PMID: 33607540 DOI: 10.1016/j.ijfoodmicro.2021.109093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 02/05/2021] [Indexed: 12/13/2022]
Abstract
Since Pseudomonas fluorescens is the main microorganism causing severe spoilage in refrigerated aquatic products, the searching for non-antibiotic antibacterial agents effective against it continues to receive increasing interest. This study aimed to investigate the antibacterial effects and mechanisms of alkyl gallic esters against P. fluorescens isolated from the Russian sturgeon (Acipenser gueldenstaedti), as well as the effectiveness in combination with chitosan films on the preservation of sturgeon meats at 4 °C. Our data shows that the alkyl chain length plays a significant role in eliciting their antibacterial activities and octyl gallate (GAC8) exhibited an outstanding inhibitory efficacy. GAC8 can rapidly enter into the membrane lipid bilayer portion to disorder the membrane, and further inhibit the growth of the P. fluorescens through interfering both tricarboxylic acid cycle related to energy supply and amino acid metabolism associated with cell membranes, suppressing oxygen consumption and disturbing the respiration chain. Moreover, the alteration in membrane fatty acids indicated that GAC8 could disrupt the composition of cell membrane fatty acids, rendering the bacteria more sensitive to the antibacterial. The SEM results also substantiate the damage of the structure of the bacterial membrane caused by GAC8. Additionally, the edible chitosan-based films incorporated with GAC8 showed the enhanced antibacterial efficacy to remarkably extend the shelf life of Russian sturgeon. Overall, our findings not only provide new insight into the mode of action of GAC8 against P. fluorescens but also demonstrate composite films containing GAC8, as a kind of safe and antibacterial material, have a great promise for application in food preservations.
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Affiliation(s)
- Run-Run Zhang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China
| | - Yu-Gang Shi
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China; Key Laboratory for Food Microbial Technology of Zhejiang Province, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China.
| | - Qing Gu
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China; Key Laboratory for Food Microbial Technology of Zhejiang Province, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China
| | - Mei Fang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China
| | - Yue-Wen Chen
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China
| | - Sheng Fang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China
| | - Ya-Li Dang
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo 315211, China.
| | - Jian-She Chen
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China; School of Food Science and Nutrition, University of Leeds, Leeds, LS2 9JT, UK
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de Oliveira EF, Yang X, Basnayake N, Huu CN, Wang L, Tikekar R, Nitin N. Screening of antimicrobial synergism between phenolic acids derivatives and UV-A light radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2020; 214:112081. [PMID: 33239223 DOI: 10.1016/j.jphotobiol.2020.112081] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 09/15/2020] [Accepted: 11/08/2020] [Indexed: 01/27/2023]
Abstract
The objective of this study was to investigate synergistic antibacterial activity based on a combination of UV-A light and three classes of food grade compounds: benzoic acid derivatives, cinnamic acid derivatives, and gallates. By using Escherichia coli O157:H7 as the model strain, it was observed that three cinnamic acid derivatives (ferulic acid, coumaric acid, and caffeic acid) and one benzoic acid derivative (2,5-dihydroxybenzoic acid) presented strong synergistic antibacterial activity with UV-A light radiation, where 1 mM levels of these compounds plus with 15 min of UV-A light (total light dose of 6.1 cm-2) led to more than 7-log CFU mL-1 of bacterial inactivation. In contrast, synergistic antibacterial activity between UV-A light and most benzoic acid derivatives (benzoic acid, gallic acid, vanillic acid, and 2,5-dimethoxybenzoic acid) were only observed after higher concentrations of these compounds were applied (10 mM). Lastly, from the three gallates tested (methyl gallate, ethyl gallate, and propyl gallate), only propyl gallate showed strong antibacterial synergism with UV-A light, where 10 mM of propyl gallate plus 15 min of UV-A light led to approximately 6.5-log of bacterial reduction. Presence of antioxidant compounds mitigated the light-mediated antibacterial activity of gallic acid, 2,5-dihydroxybenzoic acid, and propyl gallate. Similarly, the light-mediated antibacterial activity of these compounds was significantly (P < 0.05) reduced against metabolic-inhibited bacterial cells (sodium azide pretreatment). On the other hand, the antibacterial synergism between ferulic acid and UV-A light was not affected by the presence of antioxidants or the metabolic state of the bacterial cells. Due to the increasing concerns of antimicrobial resistant (AMR) pathogens, the study also investigated the proposed synergistic treatment on AMR Salmonella. Combinations of 1 mM of ferulic acid or 1 mM of 2,5-dihydroxybenzoic acid with UV-A light radiation was able to inactivate more than 6-log of a multi-drug resistant Salmonella Typhimurium strain.
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Affiliation(s)
- Erick F de Oliveira
- Department of Food Science and Technology, University of California, Davis, CA, USA; CAPES Foundation, Ministry of Education of Brazil, Brasilia, DF, Brazil
| | - Xu Yang
- Department of Food Science and Technology, University of California, Davis, CA, USA
| | - Nikeshala Basnayake
- Department of Food Science and Technology, University of California, Davis, CA, USA
| | - Cuong Nguyen Huu
- Department of Food Science and Technology, University of California, Davis, CA, USA
| | - Luxin Wang
- Department of Food Science and Technology, University of California, Davis, CA, USA
| | - Rohan Tikekar
- Department of Nutrition and Food Science, University of Maryland, College Park, MD, USA
| | - Nitin Nitin
- Department of Food Science and Technology, University of California, Davis, CA, USA; Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA.
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Jingjing E, Lili M, Zichao C, Rongze M, Qiaoling Z, Ruiyin S, Zongbai H, Junguo W. Effects of buffer salts on the freeze-drying survival rate of Lactobacillus plantarum LIP-1 based on transcriptome and proteome analyses. Food Chem 2020; 326:126849. [DOI: 10.1016/j.foodchem.2020.126849] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/16/2020] [Accepted: 04/17/2020] [Indexed: 10/24/2022]
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Kang JW, Kim WJ, Kang DH. Synergistic effect of 222-nm krypton-chlorine excilamp and mild heating combined treatment on inactivation of Escherichia coli O157:H7 and Salmonella Typhimurium in apple juice. Int J Food Microbiol 2020; 329:108665. [PMID: 32497789 DOI: 10.1016/j.ijfoodmicro.2020.108665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/20/2020] [Accepted: 05/16/2020] [Indexed: 10/24/2022]
Abstract
Simultaneous treatment with 222-nm KrCl excilamp and mild heating (EX-MH) at 45, 50 and 55 °C showed synergistic bactericidal effects on non-acid and acid adapted cells of Escherichia coli O157:H7 and Salmonella Typhimurium in apple juice. In particular, acid-adapted pathogens exhibited increased resistance to EX-MH compared to pathogenic bacteria that were not acid-adapted. Also, elucidation of the synergistic bactericidal mechanism of EX-MH was performed through several assays and this mechanism was described as follows: (i) when KrCl excilamp (EX) and mild heating (MH) are applied simultaneously, MH reversibly inactivates the antioxidant enzyme, superoxide dismutase (SOD), thereby increasing accumulation of reactive oxygen species (ROS) generated by EX and thus inducing synergistic ROS generation, (ii) ROS production induces lipid peroxidation occurrence in the cell membrane, (iii) this lipid peroxidation occurrence in the cell membrane induces synergistic destruction of cell membrane, resulting in synergistic cell death. While EX-MH of 45, 50, or 55 °C reduced E. coli O157:H7 (the pathogen most resistant to EX-MH) in apple juice by 5-log, the qualities such as color (L*, a*, and b*), total phenolic compounds (TPC), and DPPH free radical scavenging activity of apple juice did not change significantly (P > 0.05). This study not only suggests the applicability of EX-MH to the apple juice industry, but also can be used as baseline data for future relevant research.
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Affiliation(s)
- Jun-Won Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Woo-Ju Kim
- Department of Food Science and Technology, The Ohio State University, 2015 Fyffe road, Columbus, OH 43210, USA
| | - Dong-Hyun Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do 25354, Republic of Korea.
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Min B, Yoo D, Lee Y, Seo M, Kim H. Complete Genomic Analysis of Enterococcus faecium Heat-Resistant Strain Developed by Two-Step Adaptation Laboratory Evolution Method. Front Bioeng Biotechnol 2020; 8:828. [PMID: 32793575 PMCID: PMC7391244 DOI: 10.3389/fbioe.2020.00828] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/29/2020] [Indexed: 12/14/2022] Open
Abstract
Stress resistance is an important trait expected of lactic acid bacteria used in food manufacturing. Among the various sources of stress, high temperature is a key factor that interrupts bacterial growth. In this regards, constant efforts are made for the development of heat-resistant strains, but few studies were done accompanying genomic analysis to identify the causal factors of the resistance mechanisms. Furthermore, it is also thought that tolerance to multiple stresses are equally important. Herein, we isolated one Enterococcus faecium strain named BIOPOP-3 and completed a full-length genome sequence. Using this strain, a two-step adaptive laboratory evolution (ALE) method was applied to obtain a heat-resistant strain, BIOPOP-3 ALE. After sequencing the whole genome, we compared the two full-length sequences and identified one non-synonymous variant and four indel variants that could potentially confer heat resistance, which were technically validated by resequencing. We experimentally verified that the evolved strain was significantly enhanced in not only heat resistance but also acid and bile resistance. We demonstrated that the developed heat-resistant strain can be applied in animal feed manufacturing processes. The multi-stress-resistant BIOPOP-3 ALE strain developed in this study and the two-step ALE method are expected to be widely applied in industrial and academic fields. In addition, we expect that the identified variants which occurred specifically in heat-resistant strain will enhance molecular biological understanding and be broadly applied to the biological engineering field.
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Affiliation(s)
- Bonggyu Min
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - DongAhn Yoo
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
| | - Youngho Lee
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
| | - Minseok Seo
- Department of Computer Convergence Software, Korea University, Sejong, South Korea
| | - Heebal Kim
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.,Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea.,C&K Genomics Inc., Seoul, South Korea
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Guillén S, Marcén M, Mañas P, Cebrián G. Differences in resistance to different environmental stresses and non-thermal food preservation technologies among Salmonella enterica subsp. enterica strains. Food Res Int 2020; 132:109042. [DOI: 10.1016/j.foodres.2020.109042] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 01/09/2023]
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Min B, Kim K, Li V, Cho S, Kim H. Changes in Cell Membrane Fatty Acid Composition of Streptococcus thermophilus in Response to Gradually Increasing Heat Temperature. J Microbiol Biotechnol 2020; 30:739-748. [PMID: 32482940 PMCID: PMC9745660 DOI: 10.4014/jmb.1912.12053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 02/28/2020] [Indexed: 12/15/2022]
Abstract
In this study, a method of heat adaptation was implemented in an attempt to increase the upper thermal threshold of two Streptococcus thermophilus found in South Korea and identified the alterations in membrane fatty acid composition to adaptive response to heat. In order to develop heat tolerant lactic acid bacteria, heat treatment was continuously applied to bacteria by increasing temperature from 60°C until the point that no surviving cell was detected. Our results indicated significant increase in heat tolerance of heat-adapted strains compared to the wild type (WT) strains. In particular, the survival ratio of basically low heat-tolerant strain increased even more. In addition, the strains with improved heat tolerance acquired cross protection, which improved their survival ratio in acid, bile salts and osmotic conditions. A relation between heat tolerance and membrane fatty acid composition was identified. As a result of heat adaptation, the ratio of unsaturated to saturated fatty acids (UFA/SFA) and C18:1 relative concentration were decreased. C6:0 in only heatadapted strains and C22:0 in only the naturally high heat tolerant strain were detected. These results support the hypothesis, that the consequent increase of SFA ratio is a cellular response to environmental stresses such as high temperatures, and it is able to protect the cells from acid, bile salts and osmotic conditions via cross protection. This study demonstrated that the increase in heat tolerance can be utilized as a mean to improve bacterial tolerance against various environmental stresses.
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Affiliation(s)
- Bonggyu Min
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Kkotnim Kim
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Vladimir Li
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 0886, Republic of Korea
| | - Seoae Cho
- C&K genomics Inc., C-1008, H businesspark, Seoul 08826, Republic of Korea
| | - Heebal Kim
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 0886, Republic of Korea
- C&K genomics Inc., C-1008, H businesspark, Seoul 08826, Republic of Korea
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Kim SS, Choi W, Park SH, Kang DH. Mathematical modeling of ohmic heating for inactivation of acid-adapted foodborne pathogens in tomato juice. INTERNATIONAL JOURNAL OF FOOD ENGINEERING 2020. [DOI: 10.1515/ijfe-2019-0388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AbstractThe objective of the present study was to predict the inactivation trends of acid-adapted foodborne pathogens in tomato juice by ohmic heating through a numerical analysis method. The mathematical model based on finite element method (FEM) was used to simulate the multiphysics phenomena including electric heating, heat transfer, fluid dynamics, and pathogen inactivation. A cold spot was observed in the corner part of the ohmic heating chamber, where some pathogens survived even though all pathogens were inactivated elsewhere. Challenges of this study were how to reflect the increased resistance of pathogen by acid-adaptation. After simulation, we verified that inactivation level of acid-adapted foodborne pathogens by 25 Vrms/cm ohmic heating (1 kHz), predicted with the developed mathematical model, had no significant differences with experimental results (p > 0.05). Therefore, the mathematical approaches described in the present study will help juice processors determine the processing conditions necessary to ensure microbial safety at the cold point of a rectangular type batch ohmic heater.
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Affiliation(s)
- Sang-Soon Kim
- Department of Food Engineering, Dankook University, Cheonan, Chungnam, 31116, Republic of Korea
| | - Won Choi
- Department of Landscape Architecture and Rural Systems Engineering, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sang-Hyun Park
- Department of Food Science and Technology, Kongju National University, Yesan, Chungnam, 32439, Republic of Korea
| | - Dong-Hyun Kang
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
- Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 25354, Republic of Korea
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Heat Adaptation Improved Cell Viability of Probiotic Enterococcus faecium HL7 upon Various Environmental Stresses. Probiotics Antimicrob Proteins 2020; 11:618-626. [PMID: 29478227 DOI: 10.1007/s12602-018-9400-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The production of viable functional probiotics presupposes stability of strain features in the final product. In previous studies, Enterococcus faecium HL7 was found to have relatively higher cell viability after freeze-drying and the long-lasting resistance to heat (60 °C) as well as higher antimicrobial activities against some of fish and human pathogens among isolated strains. For heat adaptation, E. faecium HL7 cells were exposed to 52 °C for 15 min. After adaption, slight decreases of unsaturated membrane fatty acid ratios were confirmed through fatty acid analysis. Upon subsequent exposure to various stress conditions such as H2O2 (0.01%), ethanol (20%), acid (pH 3), and alkali (pH 12), the survival rate of heat-adapted HL7 was 103-105-fold higher than that of non-adapted one. These results highlight the potential of preconditioning treatments for maximizing survival of probiotic bacteria during development of probiotic functional foods. The cross-protection afforded by acid against thermal stress may indicate that certain common protective mechanisms are induced by both heat and acid stress. These results can be applied to enhancing the cell viability during live cell formulation of E. faecium HL7 to be used as a potential probiotics in aquaculture.
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Salmonella enterica Serovar Typhimurium Uses PbgA/YejM To Regulate Lipopolysaccharide Assembly during Bacteremia. Infect Immun 2019; 88:IAI.00758-19. [PMID: 31611279 PMCID: PMC6921655 DOI: 10.1128/iai.00758-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 10/01/2019] [Indexed: 12/14/2022] Open
Abstract
Salmonella enterica serovar Typhimurium (S Typhimurium) relies upon the inner membrane protein PbgA to enhance outer membrane (OM) integrity and promote virulence in mice. The PbgA transmembrane domain (residues 1 to 190) is essential for viability, while the periplasmic domain (residues 191 to 586) is dispensable. Residues within the basic region (residues 191 to 245) bind acidic phosphates on polar phospholipids, like for cardiolipins, and are necessary for salmonella OM integrity. S Typhimurium bacteria increase their OM cardiolipin concentrations during activation of the PhoPQ regulators. The mechanism involves PbgA's periplasmic globular region (residues 245 to 586), but the biological role of increasing cardiolipins on the surface is not understood. Nonsynonymous polymorphisms in three essential lipopolysaccharide (LPS) synthesis regulators, lapB (also known as yciM), ftsH, and lpxC, variably suppressed the defects in OM integrity, rifampin resistance, survival in macrophages, and systemic colonization of mice in the pbgAΔ191-586 mutant (in which the PbgA periplasmic domain from residues 191 to 586 is deleted). Compared to the OMs of the wild-type salmonellae, the OMs of the pbgA mutants had increased levels of lipid A-core molecules, cardiolipins, and phosphatidylethanolamines and decreased levels of specific phospholipids with cyclopropanated fatty acids. Complementation and substitution mutations in LapB and LpxC generally restored the phospholipid and LPS assembly defects for the pbgA mutants. During bacteremia, mice infected with the pbgA mutants survived and cleared the bacteria, while animals infected with wild-type salmonellae succumbed within 1 week. Remarkably, wild-type mice survived asymptomatically with pbgA-lpxC salmonellae in their livers and spleens for months, but Toll-like receptor 4-deficient animals succumbed to these infections within roughly 1 week. In summary, S Typhimurium uses PbgA to influence LPS assembly during stress in order to survive, adapt, and proliferate within the host environment.
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43
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Verheyen D, Baka M, Akkermans S, Skåra T, Van Impe JF. Effect of microstructure and initial cell conditions on thermal inactivation kinetics and sublethal injury of Listeria monocytogenes in fish-based food model systems. Food Microbiol 2019; 84:103267. [DOI: 10.1016/j.fm.2019.103267] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 05/22/2019] [Accepted: 07/10/2019] [Indexed: 01/07/2023]
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45
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Yuan W, Yuk HG. Effects of Sublethal Thymol, Carvacrol, and trans-Cinnamaldehyde Adaptation on Virulence Properties of Escherichia coli O157:H7. Appl Environ Microbiol 2019; 85:AEM.00271-19. [PMID: 31076428 DOI: 10.1128/aem.00271-19/format/epub] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/28/2019] [Indexed: 05/27/2023] Open
Abstract
Essential oils (EOs) have demonstrated wide-spectrum antimicrobial activities and have been actively studied for their application in foods as alternative natural preservatives. However, information regarding microbial adaptive responses and changes in virulence properties following sublethal EO exposure is still scarce. The present study investigated the effect of sublethal thymol (Thy), carvacrol (Car), or trans-cinnamaldehyde (TC) adaptation on virulence gene expression and virulence properties of Escherichia coli O157:H7. The results demonstrated that E. coli O157:H7 grown to the early stationary phase in the presence of sublethal EO showed significantly (P < 0.05) reduced motility (reversible after stress removal), biofilm-forming ability, and efflux pump activity, with no induction of antibiotic resistance and no significant changes to its adhesion and invasion ability on a human colon adenocarcinoma (Caco-2) cell line. Reverse transcription-quantitative PCR revealed reduced expression of relevant virulence genes, including those encoding flagellar biosynthesis and function, biofilm formation regulators, multidrug efflux pumps, and type III secretion system components. This study demonstrated that Thy, Car, and TC at sublethal concentrations did not potentiate virulence in adapted E. coli O157:H7, which could benefit to their application in the food industry.IMPORTANCE The present study was conducted to evaluate changes in virulence properties in Escherichia coli O157:H7 adapted to sublethal essential oils (EOs). The results demonstrated reduced motility, biofilm-forming ability, and efflux pump activities in EO-adapted E. coli O157:H7, with no induction of antibiotic resistance or infection (adhesion and invasion) on Caco-2 cells. Reverse transcription-quantitative PCR results revealed changes in the expression of related virulence genes. Thus, the present study provides new insights into microbial virulence behavior following EO adaptation and suggests that Thy, Car, and TC sublethal exposure did not constitute a significant risk in inducing microbial virulence.
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Affiliation(s)
- Wenqian Yuan
- Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Singapore
| | - Hyun-Gyun Yuk
- Department of Food Science and Technology, Korea National University of Transportation, Chungbuk, Republic of Korea
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46
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Effects of Sublethal Thymol, Carvacrol, and trans-Cinnamaldehyde Adaptation on Virulence Properties of Escherichia coli O157:H7. Appl Environ Microbiol 2019; 85:AEM.00271-19. [PMID: 31076428 DOI: 10.1128/aem.00271-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/28/2019] [Indexed: 01/22/2023] Open
Abstract
Essential oils (EOs) have demonstrated wide-spectrum antimicrobial activities and have been actively studied for their application in foods as alternative natural preservatives. However, information regarding microbial adaptive responses and changes in virulence properties following sublethal EO exposure is still scarce. The present study investigated the effect of sublethal thymol (Thy), carvacrol (Car), or trans-cinnamaldehyde (TC) adaptation on virulence gene expression and virulence properties of Escherichia coli O157:H7. The results demonstrated that E. coli O157:H7 grown to the early stationary phase in the presence of sublethal EO showed significantly (P < 0.05) reduced motility (reversible after stress removal), biofilm-forming ability, and efflux pump activity, with no induction of antibiotic resistance and no significant changes to its adhesion and invasion ability on a human colon adenocarcinoma (Caco-2) cell line. Reverse transcription-quantitative PCR revealed reduced expression of relevant virulence genes, including those encoding flagellar biosynthesis and function, biofilm formation regulators, multidrug efflux pumps, and type III secretion system components. This study demonstrated that Thy, Car, and TC at sublethal concentrations did not potentiate virulence in adapted E. coli O157:H7, which could benefit to their application in the food industry.IMPORTANCE The present study was conducted to evaluate changes in virulence properties in Escherichia coli O157:H7 adapted to sublethal essential oils (EOs). The results demonstrated reduced motility, biofilm-forming ability, and efflux pump activities in EO-adapted E. coli O157:H7, with no induction of antibiotic resistance or infection (adhesion and invasion) on Caco-2 cells. Reverse transcription-quantitative PCR results revealed changes in the expression of related virulence genes. Thus, the present study provides new insights into microbial virulence behavior following EO adaptation and suggests that Thy, Car, and TC sublethal exposure did not constitute a significant risk in inducing microbial virulence.
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47
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Modeling the Reduction of Salmonella spp. on Chicken Breasts and Wingettes during Scalding for QMRA of the Poultry Supply Chain in China. Microorganisms 2019; 7:microorganisms7060165. [PMID: 31174317 PMCID: PMC6617264 DOI: 10.3390/microorganisms7060165] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 11/29/2022] Open
Abstract
The objective of this study was to develop predictive models for describing the inoculated Salmonella reductions on chicken during the scalding process in China. Salmonella reductions on chicken breasts at a 100 s treatment were 1.12 ± 0.07, 1.38 ± 0.01, and 2.17 ± 0.11 log CFU/g at scalding temperatures of 50, 60 and 70 °C, respectively. For chicken wingettes, 0.87 ± 0.02, 0.99 ± 0.14 and 1.11 ± 0.17 log CFU/g reductions were obtained at 50, 60 and 70 °C after the 100 s treatment, respectively. Greater bacterial reductions were observed on chicken breasts than on chicken wingettes (p < 0.05). A logistic (−1.12, 0.06) distribution could describe the bacterial reductions on chicken breasts at 50–60 °C. Weibull, exponential and log-linear models were compared for describing the bacterial reduction on chicken breasts at 70 °C and the Weibull model showed the best fit as indicated by the pseudo-R2, root mean square error (RMSE) and standard error of prediction (SEP) values. For chicken wingettes, a logistic (−0.95, 0.07) distribution could be used to describe the bacterial reduction at 50–70 °C. The developed predictive models could provide parts of the input data for microbial risk assessment of the poultry supply chain in China.
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Xu J, Preciado-Llanes L, Aulicino A, Decker CM, Depke M, Gesell Salazar M, Schmidt F, Simmons A, Huang WE. Single-Cell and Time-Resolved Profiling of Intracellular Salmonella Metabolism in Primary Human Cells. Anal Chem 2019; 91:7729-7737. [PMID: 31117406 PMCID: PMC7006958 DOI: 10.1021/acs.analchem.9b01010] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
The
intracellular pathogen Salmonella enterica has evolved
an array of traits for propagation and invasion of the
intestinal layers. It remains largely elusive how Salmonella adjusts its metabolic states to survive inside immune host cells.
In this study, single-cell Raman biotechnology combined with deuterium
isotope probing (Raman-DIP) have been applied to reveal metabolic
changes of the typhoidal Salmonella Typhi Ty2, the
nontyphoidal Salmonella Typhimurium LT2, and a clinical
isolate Typhimurium D23580. By initially labeling the Salmonella strains with deuterium, we employed reverse labeling to track their
metabolic changes in the time-course infection of THP-1 cell line,
human monocyte-derived dendritic cells (MoDCs) and macrophages (Mf).
We found that, in comparison with a noninvasive serovar, the invasive Salmonella strains Ty2 and D23580 have downregulated metabolic
activity inside human macrophages and dendritic cells and used lipids
as alternative carbon source, perhaps a strategy to escape from the
host immune response. Proteomic analysis using high sensitivity mass
spectrometry validated the findings of Raman-DIP analysis.
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Affiliation(s)
- Jiabao Xu
- Department of Engineering Science , University of Oxford , Parks Road , Oxford OX1 3PJ , United Kingdom
| | - Lorena Preciado-Llanes
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine , University of Oxford , Oxford OX3 9DS , United Kingdom.,Translational Gastroenterology Unit, John Radcliffe Hospital , Headington, Oxford OX3 9DU , United Kingdom
| | - Anna Aulicino
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine , University of Oxford , Oxford OX3 9DS , United Kingdom.,Translational Gastroenterology Unit, John Radcliffe Hospital , Headington, Oxford OX3 9DU , United Kingdom
| | - Christoph Martin Decker
- Interfaculty Institute for Genetics and Functional Genomics , University Medicine Greifswald , Felix-Hausdorff-Str. 8 , 17475 Greifswald , Germany
| | - Maren Depke
- Interfaculty Institute for Genetics and Functional Genomics , University Medicine Greifswald , Felix-Hausdorff-Str. 8 , 17475 Greifswald , Germany
| | - Manuela Gesell Salazar
- Interfaculty Institute for Genetics and Functional Genomics , University Medicine Greifswald , Felix-Hausdorff-Str. 8 , 17475 Greifswald , Germany
| | - Frank Schmidt
- Interfaculty Institute for Genetics and Functional Genomics , University Medicine Greifswald , Felix-Hausdorff-Str. 8 , 17475 Greifswald , Germany.,Proteomics Core, Weill Cornel Medicine-Qatar , Education City , PO 24144 Doha , Qatar
| | - Alison Simmons
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine , University of Oxford , Oxford OX3 9DS , United Kingdom.,Translational Gastroenterology Unit, John Radcliffe Hospital , Headington, Oxford OX3 9DU , United Kingdom
| | - Wei E Huang
- Department of Engineering Science , University of Oxford , Parks Road , Oxford OX1 3PJ , United Kingdom
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Gómez-Baltazar A, Vázquez-Garcidueñas MS, Larsen J, Kuk-Soberanis ME, Vázquez-Marrufo G. Comparative stress response to food preservation conditions of ST19 and ST213 genotypes of Salmonella enterica serotype Typhimurium. Food Microbiol 2019; 82:303-315. [PMID: 31027788 DOI: 10.1016/j.fm.2019.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 01/30/2019] [Accepted: 03/07/2019] [Indexed: 11/27/2022]
Abstract
The replacement of the most prevalent Salmonella enterica genotypes has been documented worldwide. Here we tested the hypothesis that the current prevalent sequence type ST213 of serotype Typhimurium in Mexico has a higher resistance to stressful food preservation conditions than the displaced sequence ST19. ST19 showed higher cell viability percentages than ST213 in osmotic (685 mM NaCl) and acidic (pH 3.5) stress conditions and in combination with refrigeration (4 °C) and ambient (≈22 °C) temperatures. Both genotypes showed the same poststress recovery growth. ST213 formed biofilm and filamentous cells (FCs) under stress, whereas ST19 did not. ST213 cells also showed higher motility. The capacity of ST213 to form FCs may explain its lower viability percentages when compared with ST19, i.e., ST213 cells divided less under stress conditions, but FCs had the same recovery capacity of ST19 cells. ST213 presented a higher unsaturated/saturated fatty acids ratio (0.5-0.6) than ST19 (0.2-0.5), which indicates higher membrane fluidity. The transcript levels of the rpoS gene were similar between genotypes under the experimental conditions employed. Biofilm formation, the generation of FCs, cell motility and membrane modification seem to make ST213 more resistant than ST19 to food preservation environments.
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Affiliation(s)
- Adrián Gómez-Baltazar
- Centro Multidisciplinario de Estudios en Biotecnología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, CP 58893, Mexico.
| | - Ma Soledad Vázquez-Garcidueñas
- División de Estudios de Posgrado, Facultad de Ciencias Médicas y Biológicas "Dr. Ignacio Chávez", Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, CP 58020, Mexico.
| | - John Larsen
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad (IIES), Universidad Nacional Autónoma de México, Morelia, Michoacá, CP 58190, Mexico.
| | - Mariana Esther Kuk-Soberanis
- División de Estudios de Posgrado, Facultad de Ciencias Médicas y Biológicas "Dr. Ignacio Chávez", Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, CP 58020, Mexico.
| | - Gerardo Vázquez-Marrufo
- Centro Multidisciplinario de Estudios en Biotecnología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, CP 58893, Mexico.
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50
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López M, Calvo T, Prieto M, Múgica-Vidal R, Muro-Fraguas I, Alba-Elías F, Alvarez-Ordóñez A. A Review on Non-thermal Atmospheric Plasma for Food Preservation: Mode of Action, Determinants of Effectiveness, and Applications. Front Microbiol 2019; 10:622. [PMID: 31001215 PMCID: PMC6454144 DOI: 10.3389/fmicb.2019.00622] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 03/12/2019] [Indexed: 11/13/2022] Open
Abstract
Non-thermal Atmospheric Plasma (NTAP) is a cutting-edge technology which has gained much attention during the last decade in the food-processing sector as a promising technology for food preservation and maintenance of food safety, with minimal impact on the quality attributes of foods, thanks to its effectiveness in microbial inactivation, including of pathogens, spoilage fungi and bacterial spores, simple design, ease of use, cost-effective operation, short treatment times, lack of toxic effects, and significant reduction of water consumption. This review article provides a general overview of the principles of operation and applications of NTAP in the agri-food sector. In particular, the numerous studies carried out in the last decade aimed at deciphering the influence of different environmental factors and processing parameters on the microbial inactivation attained are discussed. In addition, this review also considers some important studies aimed at elucidating the complex mechanism of microbial inactivation by NTAP. Finally, other potential applications of NTAP in the agri-food sector, apart from food decontamination, are briefly described, and some limitations for the immediate industrial implementation of NTAP are discussed (e.g., impact on the nutritional and sensory quality of treated foods; knowledge on the plasma components and reactive species responsible for the antimicrobial activity; possible toxicity of some of the chemical species generated; scale-up by designing fit-for-purpose equipment).
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Affiliation(s)
- Mercedes López
- Department of Food Hygiene and Technology, Universidad de León, León, Spain
- Institute of Food Science and Technology, Universidad de León, León, Spain
| | - Tamara Calvo
- Department of Food Hygiene and Technology, Universidad de León, León, Spain
| | - Miguel Prieto
- Department of Food Hygiene and Technology, Universidad de León, León, Spain
- Institute of Food Science and Technology, Universidad de León, León, Spain
| | | | | | - Fernando Alba-Elías
- Department of Mechanical Engineering, Universidad de La Rioja, Logroño, Spain
| | - Avelino Alvarez-Ordóñez
- Department of Food Hygiene and Technology, Universidad de León, León, Spain
- Institute of Food Science and Technology, Universidad de León, León, Spain
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