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Champidou C, Ellouze M, Campagnoli M, Robin O, Haddad N, Membré JM. Unveiling the matrix effect on Bacillus licheniformis and Bacillus subtilis spores heat inactivation between plant-based milk alternatives, bovine milk and culture medium. Int J Food Microbiol 2024; 422:110807. [PMID: 38970999 DOI: 10.1016/j.ijfoodmicro.2024.110807] [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: 12/07/2023] [Revised: 05/22/2024] [Accepted: 06/23/2024] [Indexed: 07/08/2024]
Abstract
This study examined the inactivation of spores of Bacillus licheniformis and Bacillus subtilis in four pea-based milk alternatives, semi-skimmed bovine milk and Brain Heart Infusion (BHI) broth to assess the matrix impact on the thermal inactivation of bacterial spores. Heat inactivation was performed with the method of capillary tubes in temperature range 97-110 °C. A four-parameter non-linear model, including initial level, shoulder duration, inactivation rate and tailing, was fitted to the data obtained. D-values were estimated and secondary ZT-value models were developed for both species. A secondary model for the shoulder length of B. licheniformis in a plant-based milk alternative formulation was built too. Models were validated at a higher temperature, 113.5 °C. D-values in the different matrices ranged between 2.3 and 8.2 min at 97 °C and 0.1-0.3 min at 110 °C for B. licheniformis. D-values for B. subtilis ranged between 3.9 and 6.3 min at 97 °C and 0.2-0.3 min at 110 °C. ZT-values in the different matrices ranged between 7.3 and 8.9 °C and 8.9-10.0 °C for B. licheniformis and B. subtilis, respectively. Significant differences in inactivation parameters were found within the pea-based formulations as well as when compared to bovine milk. Heat resistance was higher in pea-based matrices. Shoulders observed were temperature- and matrix-dependent, while no such trend was found for the tailings. These results provide insights, useful on designing safe thermal processing, limiting spoilage in plant-based milk alternatives and thus, reducing global food waste.
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Affiliation(s)
- Chrysanthi Champidou
- Food Safety Research Department, Nestlé Research, PO BOX44, CH-1000 Lausanne 26, Switzerland; Oniris, INRAE, SECALIM, Nantes, France
| | - Mariem Ellouze
- Digital Food Safety Department, Nestlé Research, PO BOX44, CH-1000 Lausanne 26, Switzerland
| | - Matteo Campagnoli
- Nutrition Quality, Nestlé Product Technology Center, CH-3150 Konolfingen, Switzerland
| | - Olivier Robin
- Nutrition Quality, Nestlé Product Technology Center, CH-3150 Konolfingen, Switzerland
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Heckler C, Vale MG, Canales HDS, Stradiotto GC, Giordano ALPL, Schreiber AZ, Sant'Ana AS. Spore-forming bacteria in gelatin: Characterization, identification by 16S rRNA and MALDI-TOF mass spectrometry (MS), and presence of heat resistance and virulence genes. Int J Food Microbiol 2024; 422:110813. [PMID: 38970997 DOI: 10.1016/j.ijfoodmicro.2024.110813] [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: 02/05/2024] [Revised: 06/20/2024] [Accepted: 06/27/2024] [Indexed: 07/08/2024]
Abstract
Gelatin, a versatile protein derived from collagen, is widely used in the food, pharmaceutical and medical sectors. However, bacterial contamination by spore-forming bacteria during gelatin processing represents a significant concern for product safety and quality. In this study, an investigation was carried out to explore the heat and chemical resistance, as well as the identification and characterization of spore-forming bacteria isolated from gelatin processing. The methodologies involved chemical resistance tests with drastic pH in microplates and thermal resistance tests in capillary tubes of various isolates obtained at different processing stages. In addition, phenotypic and genotypic analyses were carried out to characterize the most resistant isolates of spore-forming bacteria. The findings of this study revealed the presence of several species, including Bacillus cereus, Bacillus licheniformis, Bacillus sonorensis, Bacillus subtilis, Geobacillus stearothermophilus, and Clostridium sporogenes, with some isolates exhibiting remarkable chemical and heat resistances. In addition, a significant proportion of the most resistant isolates showed gelatinase activity (n = 19/21; 90.5 %) and the presence of heat resistance (n = 5/21; 23.8 %), and virulence genes (n = 11/21; 52.4 %). The results of this study suggest that interventions should be done in quality control practices and that process parameter adjustments and effective contamination reduction strategies should be implemented through gelatin processing.
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Affiliation(s)
- Caroline Heckler
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, São Paulo, Brazil
| | - Matheus G Vale
- Department of Integrated Systems, Faculty of Mechanical Engineering, University of Campinas, Campinas, São Paulo, Brazil
| | - Héctor D S Canales
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, São Paulo, Brazil
| | - Graziele C Stradiotto
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, São Paulo, Brazil
| | - Ana Luisa P L Giordano
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| | - Angelica Z Schreiber
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| | - Anderson S Sant'Ana
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, São Paulo, Brazil.
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3
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Wu Y, Li J, Zhu L, Wang D, Song J, Yu X, Li Y, Tang BZ. Photosensitive AIEgens sensitize bacteria to oxidative damage and modulate the inflammatory responses of macrophages to salvage the photodynamic therapy against MRSA. Biomaterials 2024; 309:122583. [PMID: 38692148 DOI: 10.1016/j.biomaterials.2024.122583] [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: 01/17/2024] [Revised: 04/07/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
The urgent need for antimicrobial agents to combat infections caused by multidrug-resistant bacteria facilitates the exploration of alternative strategies such as photosensitizer (PS)-mediated photoinactivation. However, increasing studies have discovered uncorrelated bactericidal activities among PSs possessing similar photodynamic and pathogen-targeted properties. To optimize the photodynamic therapy (PDT) against infections, we investigated three type-I PSs of D-π-A AIEgens TI, TBI, and TTI. The capacities of reactive oxygen species (ROS) generation of TI, TBI, and TTI did not align with their bactericidal activities. Despite exhibiting the lowest photodynamic efficiency, TI exhibited the highest activities against methicillin-resistant Staphylococcus aureus (MRSA) by impairing the anti-oxidative responses of bacteria. By comparison, TTI, characterized by the strongest ROS production, inactivated intracellular MRSA by potentiating the inflammatory response of macrophages. Unlike TI and TTI, TBI, despite possessing moderate photodynamic activities and inducing ROS accumulation in both MRSA and macrophages, did not exhibit any antibacterial activity. Therefore, relying on the disturbed anti-oxidative metabolism of pathogens or potentiated host immune responses, transient ROS bursts can effectively control bacterial infections. Our study reevaluates the contribution of photodynamic activities of PSs to bacterial elimination and provides new insights into discovering novel antibacterial targets and agents.
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Affiliation(s)
- Yifan Wu
- Innovation Research Center for AIE Pharmaceutical Biology, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, The NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 511436, China; Center for AIE Research, Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China
| | - Jiangao Li
- Innovation Research Center for AIE Pharmaceutical Biology, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, The NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 511436, China; Center for AIE Research, Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China
| | - Liwei Zhu
- Innovation Research Center for AIE Pharmaceutical Biology, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, The NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 511436, China
| | - Deliang Wang
- Department of Materials Chemistry, Huzhou University, Huzhou, Zhejiang, 313000, China
| | - Jiayi Song
- Innovation Research Center for AIE Pharmaceutical Biology, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, The NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 511436, China
| | - Xiyong Yu
- Innovation Research Center for AIE Pharmaceutical Biology, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, The NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 511436, China
| | - Ying Li
- Innovation Research Center for AIE Pharmaceutical Biology, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, The NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 511436, China.
| | - Ben Zhong Tang
- Clinical Translational Research Center of Aggregation-Induced Emission, The Second Affiliated Hospital, School of Medicine, School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen (CUHK-Shenzhen), Guangdong, 518172, China.
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Yabe H, Abe H, Muramatsu Y, Koyama K, Koseki S. 3-D stochastic modeling approach in thermal inactivation: estimation of thermal survival kinetics of Escherichia coli O157:H7 in a hamburger after exposure to desiccation stress. Appl Environ Microbiol 2024; 90:e0078924. [PMID: 38780259 PMCID: PMC11218657 DOI: 10.1128/aem.00789-24] [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: 04/23/2024] [Accepted: 04/29/2024] [Indexed: 05/25/2024] Open
Abstract
Desiccation tolerance of pathogenic bacteria is one strategy for survival in harsh environments, which has been studied extensively. However, the subsequent survival behavior of desiccation-stressed bacterial pathogens has not been clarified in detail. Herein, we demonstrated that the effect of desiccation stress on the thermotolerance of Escherichia coli O157:H7 in ground beef was limited, and its thermotolerance did not increase. E. coli O157:H7 was inoculated into a ground beef hamburger after exposure to desiccation stress. We combined a bacterial inactivation model with a heat transfer model to predict the survival kinetics of desiccation-stressed E. coli O157:H7 in a hamburger. The survival models were developed using the Weibull model for two-dimensional pouched thin beef patties (ca. 1 mm), ignoring the temperature gradient in the sample, and a three-dimensional thick beef patty (ca. 10 mm), considering the temperature gradient in the sample. The two-dimensional (2-D) and three-dimensional (3-D) models were subjected to stochastic variations of the estimated Weibull parameters obtained from 1,000 replicated bootstrapping based on isothermal experimental observations as uncertainties. Furthermore, the 3-D model incorporated temperature gradients in the sample calculated using the finite element method. The accuracies of both models were validated via experimental observations under non-isothermal conditions using 100 predictive simulations. The root mean squared errors in the log survival ratio of the 2-D and 3-D models for 100 simulations were 0.25-0.53 and 0.32-2.08, respectively, regardless of the desiccation stress duration (24 or 72 h). The developed approach will be useful for setting appropriate process control measures and quantitatively assessing food safety levels.IMPORTANCEAcquisition of desiccation stress tolerance in bacterial pathogens might increase thermotolerance as well and increase the risk of foodborne illnesses. If a desiccation-stressed pathogen enters a kneaded food product via cross-contamination from a food-contact surface and/or utensils, proper estimation of the internal temperature changes in the kneaded food during thermal processing is indispensable for predicting the survival kinetics of desiccation-stressed bacterial cells. Various survival kinetics prediction models that consider the uncertainty or variability of pathogenic bacteria during thermal processing have been developed. Furthermore, heat transfer processes in solid food can be estimated using finite element method software. The present study demonstrated that combining a heat transfer model with a bacterial inactivation model can predict the survival kinetics of desiccation-stressed bacteria in a ground meat sample, corresponding to the temperature gradient in a solid sample during thermal processing. Combining both modeling procedures would enable the estimation of appropriate bacterial survival kinetics in solid food.
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Affiliation(s)
- Hidemoto Yabe
- Graduate School of Agricultural Science, Hokkaido University, Sapporo, Japan
| | - Hiroki Abe
- Institute of Food Research, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Yoshiki Muramatsu
- Department of Bioproduction and Environment Engineering, Tokyo University of Agriculture, Tokyo, Japan
| | - Kento Koyama
- Graduate School of Agricultural Science, Hokkaido University, Sapporo, Japan
| | - Shige Koseki
- Graduate School of Agricultural Science, Hokkaido University, Sapporo, Japan
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Garcia-Gutierrez E, Monteoliva García G, Bodea I, Cotter PD, Iguaz A, Garre A. A secondary model for the effect of pH on the variability in growth fitness of Listeria innocua strains. Food Res Int 2024; 186:114314. [PMID: 38729708 DOI: 10.1016/j.foodres.2024.114314] [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: 03/11/2024] [Revised: 04/11/2024] [Accepted: 04/16/2024] [Indexed: 05/12/2024]
Abstract
Variability in microbial growth is a keystone of modern Quantitative Microbiological Risk Assessment (QMRA). However, there are still significant knowledge gaps on how to model variability, with the most common assumption being that variability is constant. This is implemented by an error term (with constant variance) added on top of the secondary growth model (for the square root of the growth rate). However, this may go against microbial ecology principles, where differences in growth fitness among bacterial strains would be more prominent in the vicinity of the growth limits than at optimal growth conditions. This study coins the term "secondary models for variability", evaluating whether they should be considered in QMRA instead of the constant strain variability hypothesis. For this, 21 strains of Listeria innocua were used as case study, estimating their growth rate by the two-fold dilution method at pH between 5 and 10. Estimates of between-strain variability and experimental uncertainty were obtained for each pH using mixed-effects models, showing the lowest variability at optimal growth conditions, increasing towards the growth limits. Nonetheless, the experimental uncertainty also increased towards the extremes, evidencing the need to analyze both sources of variance independently. A secondary model was thus proposed, relating strain variability and pH conditions. Although the modelling approach certainly has some limitations that would need further experimental validation, it is an important step towards improving the description of variability in QMRA, being the first model of this type in the field.
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Affiliation(s)
- Enriqueta Garcia-Gutierrez
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, ETSIA-Universidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain; Food Bioscience Department, Teagasc Food Research Centre Moorepark, P61 C996 Fermoy, County Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, County Cork, Ireland; VistaMilk SFI Research Centre, Teagasc Moorepark, P61 C996 Fermoy, County Cork, Ireland
| | - Gonzalo Monteoliva García
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo-UPM, 28223 Pozuelo de Alarcón (Madrid), Spain
| | - Ioana Bodea
- Department of Technical and Soil Sciences, Faculty of Agriculture, University of Agricultural Science and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania
| | - Paul D Cotter
- Food Bioscience Department, Teagasc Food Research Centre Moorepark, P61 C996 Fermoy, County Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, County Cork, Ireland; VistaMilk SFI Research Centre, Teagasc Moorepark, P61 C996 Fermoy, County Cork, Ireland
| | - Asunción Iguaz
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, ETSIA-Universidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain
| | - Alberto Garre
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, ETSIA-Universidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain.
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Godínez-Oviedo A, Tamplin ML, Bowman JP, Hernández-Iturriaga M. Effects of intrinsic characteristics of Salmonella enterica strains isolated from foods and humans, and their interaction with food matrices during simulated gastric conditions. Int J Food Microbiol 2024; 413:110584. [PMID: 38295484 DOI: 10.1016/j.ijfoodmicro.2024.110584] [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: 09/18/2023] [Revised: 12/21/2023] [Accepted: 01/15/2024] [Indexed: 02/02/2024]
Abstract
The stomach's acidic pH is a crucial barrier against foodborne pathogens such as Salmonella enterica. This study investigated the survival of S. enterica under simulated oral and gastric conditions (SGC; pH 2 for 120 min) as a function of intrinsic pathogen characteristics and food matrix. Fifty-seven S. enterica strains isolated from food and human infections (previously characterized by serotype, virulotype, multi-drug resistance, isolation source, and isolation season) were subjected to SGC using water as a vehicle. Population reduction among the 57 isolates ranged from 2.7 to 4.7 log CFU, revealing that human isolates were inactivated less than food isolates (p = 0.0008). Among food strains, strains isolated during the cold season (food sampled from December to February) displayed the highest reduction (p = 0.00002). Six representatives of the 57 S. enterica strains were selected according to their virulotype and antimicrobial profile. They were further used to evaluate their survival under SGC in four food matrices (water, mango, tomato, and chicken), measuring S. enterica at 30 min intervals. The strains in chicken showed the lowest reduction and inactivation rate (1.42 ± 0.35 log CFU; 0.03 ± 0.005 min-1), followed by tomato (3.75 ± 0.57 log CFU; 0.15 ± 0.02 min-1), water (4.23 ± 0.27 log CFU; 0.17 ± 0.02 min-1), and mango (4.49 ± 0.39 log CFU; 0.17 ± 0.03 min-1). These data suggest that not all S. enterica strains have the same ability to survive under SGC, influencing the probability of arriving into the small intestine.
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Affiliation(s)
- A Godínez-Oviedo
- Departamento de Investigación y Posgrado de Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n, Col. Las Campanas, 76010 Querétaro, Qro., Mexico; Food Safety and Innovation Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart 7005, Australia
| | - M L Tamplin
- Food Safety and Innovation Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart 7005, Australia
| | - J P Bowman
- Food Safety and Innovation Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart 7005, Australia
| | - M Hernández-Iturriaga
- Departamento de Investigación y Posgrado de Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n, Col. Las Campanas, 76010 Querétaro, Qro., Mexico.
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Lee HJ, Tran MTH, Le MH, Justine EE, Kim YJ. Paraprobiotic derived from Bacillus velezensis GV1 improves immune response and gut microbiota composition in cyclophosphamide-treated immunosuppressed mice. Front Immunol 2024; 15:1285063. [PMID: 38455053 PMCID: PMC10918466 DOI: 10.3389/fimmu.2024.1285063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 01/12/2024] [Indexed: 03/09/2024] Open
Abstract
Paraprobiotics that benefit human health have the capacity to modulate innate and adaptive immune systems. In this study, we prepared the paraprobiotic from Bacillus velezensis GV1 using the heat-killing method and investigated its effects on immunity and gut microbiota in vitro and in vivo. The morphology of inactivated strain GV1 was observed using scanning electron microscopy. Treatment with GV1 promoted nitric oxide production and augmented cytokine (IL-6, IL-1β, and TNF-α) expression and secretion in RAW 264.7 macrophages. Moreover, the strain GV1 could alleviate cyclophosphamide monohydrate (CTX)-induced immunosuppression by reversing spleen damage and restoring the immune organ index, as well as by increasing the expression of immune-related cytokines (TNF-α, IL-1β, IFN-γ, and IL-2) in the spleen and thymus, respectively. Furthermore, GV1 treatment dramatically healed the CTX-damaged colon and regulated gut microbiota by increasing the relative abundance of beneficial bacterial families (Lactobacillaceae, Akkermansiaceae, and Coriobacteriaceae) and decreasing that of harmful bacterial families (Desulfovibrionaceae, Erysipelotrichaceae, and Staphylococcaceae). Thus, the heat-killed GV1 can be considered a potential immunoregulatory agent for use as a functional food or immune-enhancing medicine.
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Affiliation(s)
| | | | | | | | - Yeon-Ju Kim
- Graduate School of Biotechnology, and College of Life Science, Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
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Kyrylenko A, Eijlander RT, Alliney G, de Bos ELV, Wells-Bennik MHJ. Levels and types of microbial contaminants in different plant-based ingredients used in dairy alternatives. Int J Food Microbiol 2023; 407:110392. [PMID: 37729802 DOI: 10.1016/j.ijfoodmicro.2023.110392] [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: 03/27/2023] [Revised: 08/31/2023] [Accepted: 09/04/2023] [Indexed: 09/22/2023]
Abstract
In this study levels and types of microbial contaminants were investigated in 88 different plant-based ingredients including many that are used to manufacture dairy alternatives. Studied ingredients encompassed samples of pulses (pea, faba bean, chickpea, and mung bean), cereals/pseudocereals (oat, rice, amaranth and quinoa) and drupes (coconut, almond and cashew). The microbial analysis included: i) total viable count (TVC), ii) total aerobic mesophilic spore count (TMS), iii) heat resistant aerobic thermophilic spore count (HRTS), iv) anaerobic sulfite reducing Clostridium spore count (SRCS), and v) Bacillus cereus spore count (BCES). Microorganisms isolated from the counting plates with the highest sample dilutions were identified using 16S rRNA and MALDI-TOF MS analyses. Many of the investigated ingredients showed a high proportion of spores as part of their total aerobic mesophilic counts. In 63 % of the samples, the difference between TVC and TMS counts was 1 Log10 unit or less. This was particularly the case for the majority of pea isolates and concentrates, faba bean isolates, oat kernels and flakes, and for single samples of chickpea isolate, almond, amaranth, rice, quinoa, and coconut flours. Concentrations of TVC ranged between <1.0 and 5.3 Log10 CFU/g in different samples, and TMS varied between <1.0 and 4.1 Log10 CFU/g. Levels of HTRS, BCES and SRCS were generally low, typically around or below the LOD of 1.0 Log10 CFU/g. In total, 845 individual bacterial colonies were isolated belonging to 33 different genera. Bacillus licheniformis and B. cereus group strains were most frequently detected among Bacillus isolates, and these species originated primarily from pea and oat samples. Geobacillus stearothermophilus was the main species encountered as part of the HRTS. Among the Clostridium isolates, Clostridum sporogenes/tepidum were predominant species, which were mostly found in pea and almond samples. Strains with potential to cause foodborne infection or intoxication were typed using the PCR-based method for toxin genes detection. In the B. cereus group, 9 % of isolates contained the ces gene, 28 % contained hbl, 42 % cytK, and 69 % were positive for the nhe gene. Absence of the boNT-A and -B genes was confirmed for all isolated C. sporogenes/tepidum strains. Nearly all (98 %) B. licheniformis isolates were positive for the lchAA gene. Insight into the occurrence of microbial contaminants in plant-based ingredients, combined with knowledge of their key inactivation and growth characteristics, can be used for the microbial risk assessment and effective design of plant-based food processing conditions and formulations to ensure food safety and prevent spoilage.
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Affiliation(s)
- Alina Kyrylenko
- NIZO food research, Kernhemseweg 2, 6718 ZB Ede, the Netherlands; Wageningen University and Research, Food Microbiology, P.O. Box 17, 6700 AA Wageningen, the Netherlands.
| | | | - Giovanni Alliney
- NIZO food research, Kernhemseweg 2, 6718 ZB Ede, the Netherlands; Wageningen University and Research, Food Microbiology, P.O. Box 17, 6700 AA Wageningen, the Netherlands
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9
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Freire V, Del Río J, Gómara P, Salvador M, Condón S, Gayán E. Comparative study on the impact of equally stressful environmental sporulation conditions on thermal inactivation kinetics of B. subtilis spores. Int J Food Microbiol 2023; 405:110349. [PMID: 37591013 DOI: 10.1016/j.ijfoodmicro.2023.110349] [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: 03/08/2023] [Revised: 06/30/2023] [Accepted: 07/29/2023] [Indexed: 08/19/2023]
Abstract
Control of bacterial spores continues to be one of the main challenges for the food industry due to their wide dissemination and extremely high resistance to processing methods. Furthermore, the large variability in heat resistance in spores that contaminate foods makes it difficult to establish general processing conditions. Such heterogeneity not only derives from inherent differences among species and strains, but also from differences in sporulation environments that are generally ignored in spores encountered in foods. We evaluated heat inactivation kinetics and the thermodependency of resistance parameters in B. subtilis 168 spores sporulated at adverse temperatures, water activity (aw), and pH, applying an experimental approach that allowed us to quantitatively compare the impact of each condition. Reduction of incubation temperature from the optimal temperature dramatically reduced thermal resistance, and it was the most influential factor, especially at the highest treatment temperatures. These spores were also more sensitive to chemicals presumably acting in the inner membrane. Reducing sporulation aw increased heat resistance, although the magnitude of that effect depended on the solute and the treatment temperature. Thus, changes in sporulation environments varied 3D100°C values up to 10.4-fold and z values up to 1.7-fold, highlighting the relevance of taking such a source of variability into account when setting heat processing conditions. UV-C treatment and sodium hypochlorite efficiently inactivated all spore populations, including heat-resistant ones produced at low aw.
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Affiliation(s)
- Víctor Freire
- Department of Animal Production and Food Science, AgriFood Institute of Aragon (IA2), University of Zaragoza-CITA, Faculty of Veterinary, Miguel Servet 177, 50013 Zaragoza, Spain
| | - Javier Del Río
- Department of Animal Production and Food Science, AgriFood Institute of Aragon (IA2), University of Zaragoza-CITA, Faculty of Veterinary, Miguel Servet 177, 50013 Zaragoza, Spain
| | - Paula Gómara
- Department of Animal Production and Food Science, AgriFood Institute of Aragon (IA2), University of Zaragoza-CITA, Faculty of Veterinary, Miguel Servet 177, 50013 Zaragoza, Spain
| | - Maika Salvador
- Department of Animal Production and Food Science, AgriFood Institute of Aragon (IA2), University of Zaragoza-CITA, Faculty of Veterinary, Miguel Servet 177, 50013 Zaragoza, Spain
| | - Santiago Condón
- Department of Animal Production and Food Science, AgriFood Institute of Aragon (IA2), University of Zaragoza-CITA, Faculty of Veterinary, Miguel Servet 177, 50013 Zaragoza, Spain
| | - Elisa Gayán
- Department of Animal Production and Food Science, AgriFood Institute of Aragon (IA2), University of Zaragoza-CITA, Faculty of Veterinary, Miguel Servet 177, 50013 Zaragoza, Spain.
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10
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Rodriguez-Caturla MY, Garre A, Castillo CJC, Zwietering MH, den Besten HMW, SantˈAna AS. Shelf life estimation of refrigerated vacuum packed beef accounting for uncertainty. Int J Food Microbiol 2023; 405:110345. [PMID: 37549599 DOI: 10.1016/j.ijfoodmicro.2023.110345] [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: 04/11/2022] [Revised: 07/24/2023] [Accepted: 07/27/2023] [Indexed: 08/09/2023]
Abstract
This study estimates the shelf life of vacuum packed beef meat (three muscles: striploin (longissimus thoracis et lumborum, LTL), tenderloin (psoas major, PM) and outside chuck (trapezius thoracis, TT)) at refrigeration temperatures (0 °C-10 °C) based on modelling the growth of two relevant groups of spoilage microorganisms: lactic acid bacteria (LAB) and Enterobacteriaceae. The growth models were developed combining a two-step and a one-step approach. The primary modelling was used to identify the parameters affecting the growth kinetics, guiding the definition of secondary growth models. For LAB, the secondary model included the effect of temperature and initial pH on the specific growth rate. On the other hand, the model for Enterobacteriaceae incorporated the effect of temperature on the specific growth rate and the lag phase; as well as the effect of the initial pH on the specific growth rate, the lag phase and the initial microbial count. We did not observe any significant effect of the type of muscle on the growth kinetics. Once the equations were defined, the models were fitted to the complete dataset using a one-step approach. Model validation was carried out by cross-validation, mitigating the impact of an arbitrary division between training and validation sets. The models were used to estimate the shelf life of the product, based on the maximum admissible microbial concentration (7 log CFU/g for LAB, 5 log CFU/g for Enterobacteriaceae). Although LAB was the dominant microbiota, in several cases, both LAB and Enterobacteriaceae reached the critical concentration practically at the same time. Furthermore, in some scenarios, the end of shelf life would be determined by Enterobacteriaceae, pointing at the potential importance of non-dominant microorganisms for product spoilage. These results can aid in the implementation of effective control measures in the meat processing industry.
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Affiliation(s)
- Magdevis Y Rodriguez-Caturla
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Alberto Garre
- Food Microbiology, Wageningen University, PO Box 17, 6700 AA Wageningen, the Netherlands
| | - Carmen Josefina Contreras Castillo
- Department of Agroindustry, Food and Nutrition, Luis Queiroz College of Agriculture, University of São Paulo, Piracicaba Campus, SP, Brazil
| | - Marcel H Zwietering
- Food Microbiology, Wageningen University, PO Box 17, 6700 AA Wageningen, the Netherlands
| | - Heidy M W den Besten
- Food Microbiology, Wageningen University, PO Box 17, 6700 AA Wageningen, the Netherlands
| | - Anderson S SantˈAna
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil.
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11
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Garre A, Zwietering MH, den Besten HMW. The importance of what we cannot observe: Experimental limitations as a source of bias for meta-regression models in predictive microbiology. Int J Food Microbiol 2023; 387:110045. [PMID: 36549087 DOI: 10.1016/j.ijfoodmicro.2022.110045] [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: 07/14/2022] [Revised: 11/22/2022] [Accepted: 11/27/2022] [Indexed: 12/12/2022]
Abstract
Meta-regression models have gained in popularity during the last years as a way to create more generic models for Microbial Risk Assessments that also include variability. However, as with most meta-analyses and empirical models, systematic biases in the data can result in inaccurate models. In this article, we define experimental bias as a type of selection bias due to the practical limitations of microbial inactivation experiments. Conditions with extremely high D-values (i.e. slow inactivation) need very long experimental runs to cause significant reductions. On the other hand, when the D-value is extremely low, not enough data points can be gathered before the microbial population is below the detection limit. Consequently, experimental designs favour conditions within a practical experimental range, introducing a selection bias in the D-values. We demonstrate the impact of experimental bias in meta-regression models using numerical simulations. Models fitted to data with experimental bias overestimated the z-value and underestimated variability. We propose a rapid heuristic method to identify experimental bias in datasets, and we propose truncated regression to mitigate its impact in meta-regression models. Both methods were validated using simulated data. Thereafter the procedures were tested by building a meta-regression model for actual data for the inactivation of Bacillus cereus spores. We concluded that the dataset included experimental bias, and that it would cause an overestimation of the microbial resistance at high temperatures (>120 °C) for classical meta-regression models. This effect was mitigated when the model was built using truncated regression. In conclusion, we demonstrate that experimental bias could potentially result in inaccurate models for predictive microbiology. Therefore, checking for experimental bias should be a routine step in meta-regression modelling, and be included in guidelines on data analysis for meta-regression.
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Affiliation(s)
- Alberto Garre
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - Marcel H Zwietering
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - Heidy M W den Besten
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700, AA, Wageningen, the Netherlands.
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12
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Emamjomeh M, Mohd Hashim A, Abdul-Mutalib NA, Khairil Mokhtar NF, Mustapha NA, Maeda T, Amin-Nordin S. Profiling bacterial communities and foodborne pathogens on food-associated surface following contact with raw beef, chicken and pork using 16S amplicon metagenomics. Food Control 2023. [DOI: 10.1016/j.foodcont.2023.109698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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13
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Garre A, Pielaat A, Zwietering MH, den Besten HM, Smid JH. Critical comparison of statistical methods for quantifying variability and uncertainty of microbial responses from experimental data. Int J Food Microbiol 2022; 383:109935. [DOI: 10.1016/j.ijfoodmicro.2022.109935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 09/09/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022]
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14
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Santos FRD, Leite Júnior BRDC, Tribst AAL. Kinetic parameters of microbial thermal death in goat cheese whey and growth of surviving microorganisms under refrigeration. J FOOD PROCESS ENG 2022. [DOI: 10.1111/jfpe.14191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Li Y, Liu X, Cui Z, Zheng Y, Jiang H, Zhang Y, Liang Y, Li Z, Zhu S, Wu S. Treating Multi-Drug-Resistant Bacterial Infections by Functionalized Nano-Bismuth Sulfide through the Synergy of Immunotherapy and Bacteria-Sensitive Phototherapy. ACS NANO 2022; 16:14860-14873. [PMID: 36094899 DOI: 10.1021/acsnano.2c05756] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Owing to its flexibility and high treatment efficiency, phototherapy is rapidly emerging for treating bacteria-induced diseases, but how to improve the sensitivity of bacteria to reactive oxygen species (ROS) and heat simultaneously to kill bacteria under mild conditions is still a challenge. Herein, we designed a NIR light catalyst (Bi2S3-S-nitrosothiol-acetylcholine (BSNA)) by transforming •O2- into peroxynitrite in situ, which can enhance the bacterial sensibility to ROS and heat and kill bacteria under a mild temperature. The transformed peroxynitrite in situ possessed a stronger ability to penetrate cell membranes and antioxidant capacity. The BSNA nanoparticles (NPs) inhibited the bacterial glucose metabolic process through down-regulated xerC/xerD expression and disrupted the HSP70/HSP90 secondary structure through nitrifying TYR179. Additionally, the synergistic effect of the designed BSNA and clinical antibiotics increased the antibacterial activity. In the case of tetracycline-class antibiotics, BSNA NPs induced phenolic hydroxyl group structure changes and inhibited the interaction between tetracycline and targeted t-RNA recombinant protein. Besides, BSNA stimulated production of more CD8+ T cells and reduced common complications in peritonitis, which provided immunotherapy activity. The targeted and anti-infective effect of BSNA suggested that we propose a nanotherapeutic strategy to achieve more efficient synergistic therapy under mild temperatures.
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Affiliation(s)
- Yuan Li
- School of Materials Science & Engineering, Peking University, Beijing 100871, China
- The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, School of Materials Science & Engineering, Tianjin University, Tianjin 300072, P.R. China
| | - Xiangmei Liu
- School of Health Science & Biomedical Engineering, Hebei University of Technology, Xiping Avenue 5340, Beichen District, Tianjin 300401, P.R. China
| | - Zhenduo Cui
- The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, School of Materials Science & Engineering, Tianjin University, Tianjin 300072, P.R. China
| | - Yufeng Zheng
- The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, School of Materials Science & Engineering, Tianjin University, Tianjin 300072, P.R. China
| | - Hui Jiang
- The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, School of Materials Science & Engineering, Tianjin University, Tianjin 300072, P.R. China
| | - Yu Zhang
- Department of Orthopedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Yanqin Liang
- The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, School of Materials Science & Engineering, Tianjin University, Tianjin 300072, P.R. China
| | - Zhaoyang Li
- The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, School of Materials Science & Engineering, Tianjin University, Tianjin 300072, P.R. China
| | - Shengli Zhu
- The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, School of Materials Science & Engineering, Tianjin University, Tianjin 300072, P.R. China
| | - Shuilin Wu
- School of Materials Science & Engineering, Peking University, Beijing 100871, China
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16
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Iacumin L, Pellegrini M, Colautti A, Orecchia E, Comi G. Microbial Characterization of Retail Cocoa Powders and Chocolate Bars of Five Brands Sold in Italian Supermarkets. Foods 2022; 11:foods11182753. [PMID: 36140882 PMCID: PMC9497492 DOI: 10.3390/foods11182753] [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: 08/20/2022] [Revised: 08/29/2022] [Accepted: 09/03/2022] [Indexed: 11/30/2022] Open
Abstract
A microbial characterization of cocoa powder and chocolate bars of three batches of five different brands sold in Italian markets was performed. The results showed a variable microbial population consisting of mesophilic and thermophilic spore formation in both types of products. The chocolate bars were also contaminated with molds of environmental origin. Bacillus spp. and Geobacillus spp. were found in both products. The chocolate bars were also contaminated by molds belonging to the genera Penicillium and Cladosporium. The sporogenous strains mainly originate from the raw materials, i.e., cocoa beans, as the heat treatments involved (roasting of the beans and conching of the chocolate) are not sufficient to reach commercial sterility. Furthermore, the identified spore-forming species have often been isolated from cocoa beans. The molds isolated from chocolate seem to have an origin strictly linked to the final phases of production (environment and packaging). However, the level of contaminants is limited (<2 log CFU/g); the molds do not develop in both products due to their low Aw (<0.6) and do not affect the safety of the products. However, a case of mold development in chocolate bars was observed. Among the isolated molds, only Penicillium lanosocoeruleum demonstrated a high xero-tolerance and grew under some conditions on chocolate bars. Its growth could be explained by a cocoa butter bloom accompanied by the presence of humidity originating from the bloom or acquired during packaging.
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17
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Dikec J, Bechoua N, Winckler P, Perrier-Cornet JM. Effects of pulsed near infrared light (NIR) on Bacillus subtilis spores. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 234:112530. [PMID: 35930949 DOI: 10.1016/j.jphotobiol.2022.112530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/13/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
In this study, we develop a characterization of bacterial spore resistance to NIR pulsed light under modalities traditionally used in multiphoton microscopy. Energy dose and laser power are both key parameters in spore and bacterial cell inactivation. Surprisingly, spores and vegetative cells seem to show a similar sensitivity to pulsed NIR, spores being only 2-fold more resistant than their vegetative counterparts. This work enables us to eliminate certain hypotheses concerning the main driver of spore inactivation processes. Our findings suggest that damage leading to inactivation is mainly caused by photochemical reactions characterized by multiple possible pathways, including DNA damage or oxidation processes.
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Affiliation(s)
- J Dikec
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - N Bechoua
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - P Winckler
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - J M Perrier-Cornet
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France.
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18
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Garre A, Zwietering MH, van Boekel MAJS. The Most Probable Curve method - A robust approach to estimate kinetic models from low plate count data resulting in reduced uncertainty. Int J Food Microbiol 2022; 380:109871. [PMID: 35985079 DOI: 10.1016/j.ijfoodmicro.2022.109871] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/03/2022] [Accepted: 08/06/2022] [Indexed: 11/19/2022]
Abstract
A novel method is proposed for fitting microbial inactivation models to data on liquid media: the Most Probable Curve (MPC) method. It is a multilevel model that makes a separation between the "true" microbial concentration according to the model, the "actual" concentration in the media considering chance, and the actual counts on the plate. It is based on the assumptions that stress resistance is homogeneous within a microbial population, and that there is no aggregation of microbial cells. Under these assumptions, the number of colonies in/on a plate follows a Poisson distribution with expected value depending on the proposed kinetic model, the number of dilutions and the plated volume. The novel method is compared against (non)linear regression based on a normal likelihood distribution (traditional method), Poisson regression and gamma-Poisson regression using data on the inactivation of Listeria monocytogenes. The conclusion is that the traditional method has limitations when the data includes plates with low (or zero) cell counts, which can be mitigated using more complex (discrete) likelihoods. However, Poisson regression uses an unrealistic likelihood function, making it unsuitable for survivor curves with several log-reductions. Gamma-Poisson regression uses a more realistic likelihood function, even though it is based mostly on empirical hypotheses. We conclude that the MPC method can be used reliably, especially when the data includes plates with low or zero counts. Furthermore, it generates a more realistic description of uncertainty, integrating the contribution of the plating error and reducing the uncertainty of the primary model parameters. Consequently, although it increases modelling complexity, the MPC method can be of great interest in predictive microbiology, especially in studies focused on variability analysis.
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Affiliation(s)
- Alberto Garre
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Marcel H Zwietering
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Martinus A J S van Boekel
- Food Quality & Design, Wageningen University & Research, P.O. Box 17, 6700 AA Wageningen, the Netherlands.
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19
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Different model hypotheses are needed to account for qualitative variability in the response of two strains of Salmonella spp. under dynamic conditions. Food Res Int 2022; 158:111477. [DOI: 10.1016/j.foodres.2022.111477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/01/2022] [Accepted: 06/04/2022] [Indexed: 11/18/2022]
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20
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Sun R, Vermeulen A, Devlieghere F. Extension of growth/no growth predictive models for the preservation of low-acid pasteurized sauces by incorporating water activity and model validation in sauces. Int J Food Microbiol 2022; 378:109826. [DOI: 10.1016/j.ijfoodmicro.2022.109826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 10/17/2022]
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21
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van den Brule T, Punt M, Seekles SJ, Segers FJ, Houbraken J, Hazeleger WC, Ram AF, Wösten HA, Zwietering MH, Dijksterhuis J, den Besten HM. Intraspecific variability in heat resistance of fungal conidia. Food Res Int 2022; 156:111302. [DOI: 10.1016/j.foodres.2022.111302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/21/2022] [Accepted: 04/23/2022] [Indexed: 11/29/2022]
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22
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Boix E, Coroller L, Couvert O, Planchon S, van Vliet AH, Brunt J, Peck MW, Rasetti-Escargueil C, Lemichez E, Popoff MR, André S. Synergistic interaction between pH and NaCl in the limits of germination and outgrowth of Clostridium sporogenes and Group I Clostridium botulinum vegetative cells and spores after heat treatment. Food Microbiol 2022; 106:104055. [DOI: 10.1016/j.fm.2022.104055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 11/04/2022]
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23
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Kinetics of heat-induced changes in dairy products: Developments in data analysis and modelling techniques. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2021.105187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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24
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Le Marc Y, Postollec F, Huchet V, Ellouze M. Modelling the thermal inactivation of spores from different phylogenetic groups of Bacillus cereus. Int J Food Microbiol 2022; 368:109607. [DOI: 10.1016/j.ijfoodmicro.2022.109607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/29/2021] [Accepted: 02/27/2022] [Indexed: 11/29/2022]
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25
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Enhanced high hydrostatic pressure lethality in acidulated raw pet food formulations was pathogen species and strain dependent. Food Microbiol 2022; 104:104002. [DOI: 10.1016/j.fm.2022.104002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/30/2022] [Accepted: 02/03/2022] [Indexed: 12/12/2022]
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26
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Garre A, den Besten HM, Fernandez PS, Zwietering MH. Not just variability and uncertainty; the relevance of chance for the survival of microbial cells to stress. Trends Food Sci Technol 2021. [DOI: 10.1016/j.tifs.2021.10.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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27
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Kanaan J, Murray J, Higgins R, Nana M, DeMarco AM, Korza G, Setlow P. Resistance properties and the role of the inner membrane and coat of Bacillus subtilis spores with extreme wet heat resistance. J Appl Microbiol 2021; 132:2157-2166. [PMID: 34724311 DOI: 10.1111/jam.15345] [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: 08/24/2021] [Revised: 10/01/2021] [Accepted: 10/28/2021] [Indexed: 11/27/2022]
Abstract
AIMS A protein termed 2Duf greatly increases wet heat resistance of Bacillus subtilis spores. The current work examines the effects of 2Duf on spore resistance to other sporicides, including chemicals that act on or must cross spores' inner membrane (IM), where 2Duf is likely present. The overall aim was to gain a deeper understanding of how 2Duf affects spore resistance, and of spore resistance itself. METHODS AND RESULTS 2Duf's presence increased spore resistance to chemicals that damage or must cross the IM to kill spores. Spore coat removal decreased 2Duf-spore resistance to chemicals and wet heat, and 2Duf-spores made at higher temperatures were more resistant to wet heat and chemicals. 2Duf-less spores lacking coats and Ca-dipicolinic acid were also extremely sensitive to wet heat and chemicals that transit the IM to kill spores. CONCLUSIONS The new work plus previous results lead to a number of important conclusions as follows. (1) 2Duf may influence spore resistance by decreasing the permeability of and lipid mobility in spores' IM. (2) Since wet heat-killed spores that germinate do not accumulate ATP, wet heat may inactivate some spore IM protein essential in ATP production which is stabilized in a more rigid IM. (3) Both Ca-dipicolinic acid and the spore coat play an important role in the permeability of the spore IM, and thus in many spore resistance properties. SIGNIFICANCE AND IMPACT OF THE STUDY The work in this manuscript gives a new insight into mechanisms of spore resistance to chemicals and wet heat, to the understanding of spore wet heat killing, and the role of Ca-dipicolinic acid and the coat in spore resistance.
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Affiliation(s)
- Julia Kanaan
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Jillian Murray
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Ryan Higgins
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Mishil Nana
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Angela M DeMarco
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - George Korza
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
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28
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Sinnelä MT, Pawluk AM, Jin YH, Kim D, Mah JH. Effect of Calcium and Manganese Supplementation on Heat Resistance of Spores of Bacillus Species Associated With Food Poisoning, Spoilage, and Fermentation. Front Microbiol 2021; 12:744953. [PMID: 34707595 PMCID: PMC8542979 DOI: 10.3389/fmicb.2021.744953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/22/2021] [Indexed: 11/30/2022] Open
Abstract
Bacterial spores often survive thermal processing used in the food industry, while heat treatment leads not only to a decrease in the nutritional and organoleptic properties of foods, but also to a delay in fermentation of fermented foods. Selective reduction of undesirable spores without such impediments is an ongoing challenge for food scientists. Thus, increased knowledge of the spore-forming bacteria is required to control them. In this study, the heat resistance results (D100°C) of the spores of four Bacillus species were determined and compared to previous literature, and found that B. cereus has significantly lower heat resistance than the other Bacillus species, B. coagulans, B. subtilis, and B. licheniformis. Using the spores of these strains, this study also evaluated the effects of single and combined supplementation of calcium (0.00–2.00 mM) and manganese (0.00–0.50 mM) on heat resistance (D100°C). The results revealed that the spores of B. licheniformis and B. cereus displayed the smallest heat resistance when sporulated on media rich in calcium. Conversely, B. coagulans spores and B. subtilis spores exhibited the greatest heat resistance when sporulated under calcium-rich conditions. The opposite results (stronger heat resistance for B. licheniformis spores and B. cereus spores, and smaller heat resistance for B. coagulans spores and B. subtilis spores) were obtained when the spores were formed on media poor in the minerals (particularly calcium). Based on the results, the Bacillus species were divided into two groups: B. licheniformis and B. cereus; and B. coagulans and B. subtilis. The study provides valuable insight to selectively reduce spores of undesirable Bacillus species in the food industry.
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Affiliation(s)
| | | | - Young Hun Jin
- Department of Food and Biotechnology, Korea University, Sejong, South Korea
| | - Dabin Kim
- Department of Food and Biotechnology, Korea University, Sejong, South Korea
| | - Jae-Hyung Mah
- Department of Food and Biotechnology, Korea University, Sejong, South Korea
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29
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Chiara M, Giulia T, Federica B, Diego M, Robin D, Fausto G, Stefania A. Listeria monocytogenes sensitivity to antimicrobial treatments depends on cell origin. Sci Rep 2021; 11:21263. [PMID: 34711898 PMCID: PMC8553832 DOI: 10.1038/s41598-021-00767-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022] Open
Abstract
In this study we investigated how cell origin could affect the efficacy of an antimicrobial treatment (mild heating combined with terpenoids) in Listeria monocytogenes Scott A, considering cells from: 1. single colony, 2. glycerol stock, 3. cold adapted culture, and 4. fresh culture in stationary phase. After treatment, culturability on BHI medium and viability assessed by flow cytometry were evaluated. Our results showed that the cell origin significantly impacted viability and culturability of L. monocytogenes towards antimicrobial treatment. The mild heat treatment combined or not with terpenoids mainly affected culturability rather than viability, although the culturability of cells from single colony was less impacted. Therefore, to mimic the worst scenario, these latter were selected to contaminate Gorgonzola rind and roast beef slices and we evaluated the ability of L. monocytogenes cells to recover their culturability (on ALOA agar medium) and to growth on the food matrix stored at 4 °C for 7 days. Our results suggest that only Gorgonzola rind allowed a partial recovery of the culturability of cells previously heated in presence or not of terpens. In conclusion, we found a connection between the cell history and sensitivity toward an antimicrobial treatment, underlying the importance to standardize the experimental procedures (starting from the cells to be used in the assay) in the assessment of cell sensitivity to a specific treatment. Finally, our study clearly indicated that VBNC cells can resuscitate under favorable conditions on a food matrix, becoming a threat for consumer’s health.
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Affiliation(s)
- Montanari Chiara
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy.,Interdepartmental Center for Industrial Agri-Food Research, University of Bologna, Bologna, Italy
| | - Tabanelli Giulia
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy.,Interdepartmental Center for Industrial Agri-Food Research, University of Bologna, Bologna, Italy
| | - Barbieri Federica
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - Mora Diego
- Department of Food, Environmental and Nutritional Sciences (DeFENS), Università Degli Studi di Milano, Via Celoria 2, 20133, Milan, Italy
| | - Duncan Robin
- Department of Food, Environmental and Nutritional Sciences (DeFENS), Università Degli Studi di Milano, Via Celoria 2, 20133, Milan, Italy
| | - Gardini Fausto
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy.,Interdepartmental Center for Industrial Agri-Food Research, University of Bologna, Bologna, Italy
| | - Arioli Stefania
- Department of Food, Environmental and Nutritional Sciences (DeFENS), Università Degli Studi di Milano, Via Celoria 2, 20133, Milan, Italy.
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Abstract
Food safety is one of the main challenges of the agri-food industry that is expected to be addressed in the current environment of tremendous technological progress, where consumers' lifestyles and preferences are in a constant state of flux. Food chain transparency and trust are drivers for food integrity control and for improvements in efficiency and economic growth. Similarly, the circular economy has great potential to reduce wastage and improve the efficiency of operations in multi-stakeholder ecosystems. Throughout the food chain cycle, all food commodities are exposed to multiple hazards, resulting in a high likelihood of contamination. Such biological or chemical hazards may be naturally present at any stage of food production, whether accidentally introduced or fraudulently imposed, risking consumers' health and their faith in the food industry. Nowadays, a massive amount of data is generated, not only from the next generation of food safety monitoring systems and along the entire food chain (primary production included) but also from the Internet of things, media, and other devices. These data should be used for the benefit of society, and the scientific field of data science should be a vital player in helping to make this possible.
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Affiliation(s)
- George-John Nychas
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, School of Food and Nutritional Sciences, Agricultural University of Athens, 11855 Athens, Greece;
| | - Emma Sims
- Bioinformatics Group, Department of Agrifood, School of Water, Energy and Environment, Cranfield University, Cranfield, Bedfordshire MK43 0AL, United Kingdom
| | - Panagiotis Tsakanikas
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, School of Food and Nutritional Sciences, Agricultural University of Athens, 11855 Athens, Greece;
| | - Fady Mohareb
- Bioinformatics Group, Department of Agrifood, School of Water, Energy and Environment, Cranfield University, Cranfield, Bedfordshire MK43 0AL, United Kingdom
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31
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Koyama K, Ranta J, Takeoka K, Abe H, Koseki S. Evaluation of Strain Variability in Inactivation of Campylobacter jejuni in Simulated Gastric Fluid by Using Hierarchical Bayesian Modeling. Appl Environ Microbiol 2021; 87:e0091821. [PMID: 34047637 PMCID: PMC8315736 DOI: 10.1128/aem.00918-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 05/16/2021] [Indexed: 11/20/2022] Open
Abstract
This study was conducted to quantitatively evaluate the variability of stress resistance in different strains of Campylobacter jejuni and the uncertainty of such strain variability. We developed Bayesian statistical models with multilevel analysis to quantify variability within a strain, variability between different strains, and the uncertainty associated with these estimates. Furthermore, we measured the inactivation of 11 strains of C. jejuni in simulated gastric fluid with low pH, using the Weibullian survival model. The model was first developed for separate pH conditions and then analyzed over a range of pH levels. We found that the model parameters developed under separate pH conditions exhibited a clear dependence of survival on pH. In addition, the uncertainty of the variability between different strains could be described as the joint distribution of the model parameters. The latter model, including pH dependency, accurately predicted the number of surviving cells in individual as well as multiple strains. In conclusion, variabilities and uncertainties in inactivation could be simultaneously evaluated and interpreted via a probabilistic approach based on Bayesian theory. Such hierarchical Bayesian models could be useful for understanding individual-strain variability in quantitative microbial risk assessment. IMPORTANCE Since microbial strains vary in their growth and inactivation patterns in food materials, it is important to accurately predict these patterns for quantitative microbial risk assessment. However, most previous studies in this area have used highly resistant strains, which could lead to inaccurate predictions. Moreover, variability, including measurement errors and variability within a strain and between different strains, can contribute to predicted individual-level outcomes. Therefore, a multilevel framework is required to resolve these levels of variability and estimate their uncertainties. We developed a Bayesian predictive model for the survival of Campylobacter jejuni under simulated gastric conditions taking into account the variabilities and uncertainties. We demonstrated a high correspondence between predictions from the model and empirical measurements. The modeling procedure proposed in this study recommends a novel framework for predicting pathogen behavior, which can help improve quantitative microbial risk assessment during food production and distribution.
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Affiliation(s)
- Kento Koyama
- Graduate School of Agricultural Science, Hokkaido University, Sapporo, Japan
| | - Jukka Ranta
- Risk Assessment Unit, Finnish Food Authority, Helsinki, Finland
| | - Kohei Takeoka
- Graduate School of Agricultural Science, Hokkaido University, Sapporo, Japan
| | - Hiroki Abe
- Graduate School of Agricultural Science, Hokkaido University, Sapporo, Japan
| | - Shige Koseki
- Graduate School of Agricultural Science, Hokkaido University, Sapporo, Japan
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32
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Saeed BQ, Osaili TM, Taha S. Foodborne diseases risk factors associated with food safety knowledge and practices of women in Sharjah-United Arab Emirate. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.108024] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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33
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van Boekel MAJS. To pool or not to pool: That is the question in microbial kinetics. Int J Food Microbiol 2021; 354:109283. [PMID: 34140188 DOI: 10.1016/j.ijfoodmicro.2021.109283] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/19/2021] [Accepted: 05/30/2021] [Indexed: 11/17/2022]
Abstract
Variation observed in heat inactivation of Salmonella strains (data from Combase) was characterized using multilevel modeling with two case studies. One study concerned repetitions at one temperature, the other concerned isothermal experiments at various temperatures. Multilevel models characterize variation at various levels and handle dependencies in the data. The Weibull model was applied using Bayesian regression. The research question was how parameters varied with experimental conditions and how data can best be analyzed: no pooling (each experiment analyzed separately), complete pooling (all data analyzed together) or partial pooling (connecting the experiments while allowing for variation between experiments). In the first case study, level 1 consisted of the measurements, level 2 of the group of repetitions. While variation in the initial number parameter was low (set by the researchers), the Weibull shape factor varied for each repetition from 0.58-1.44, and the rate parameter from 0.006-0.074 h. With partial pooling variation was much less, with complete pooling variation was strongly underestimated. In the second case study, level 1 consisted of the measurements, level 2 of the group of repetitions per temperature experiment, level 3 of the cluster of various temperature experiments. The research question was how temperature affected the Weibull parameters. Variation in initial numbers was low (set by the researchers), the rate parameter was obviously affected by temperature, the estimate of the shape parameter depended on how the data were analyzed. With partial pooling, and one-step global modeling with a Bigelow-type model for the rate parameter, shape parameter variation was minimal. Model comparison based on prediction capacity of the various models was explored. The probability distribution of calculated decimal reduction times was much narrower using multilevel global modeling compared to the usual single level two-step approach. Multilevel modeling of microbial heat inactivation appears to be a suitable and powerful method to characterize and quantify variation at various levels. It handles possible dependencies in the data, and yields unbiased parameter estimates. The answer on the question "to pool or not to pool" depends on the goal of modeling, but if the goal is prediction, then partial pooling using multilevel modeling is the answer, provided that the experimental data allow that.
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Affiliation(s)
- M A J S van Boekel
- Food Quality & Design Group, Wageningen University & Research, the Netherlands.
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34
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Hansen TB, Abdalas S, Al-Hilali I, Hansen LT. Predicting the effect of salt on heat tolerance of Listeria monocytogenes in meat and fish products. Int J Food Microbiol 2021; 352:109265. [PMID: 34116257 DOI: 10.1016/j.ijfoodmicro.2021.109265] [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: 06/01/2020] [Revised: 01/22/2021] [Accepted: 05/23/2021] [Indexed: 10/21/2022]
Abstract
Listeria monocytogenes is a potentially fatal foodborne pathogen that can be found in various ready-to-eat (RTE) products. It tolerates adverse conditions such as high salt concentrations and refrigerated storage, thus, the elimination of the pathogen in food processing often relies on heat processing. The objective of this study was to create a model to predict the effect of salt on heat tolerance of L. monocytogenes in meat and seafood products during heat treatments conducted at 57 to 65 °C to reduce numbers by ≥3 log10 cycles. Salt concentrations, up to 6% in the water phase (WPS%), were applied to cover a variety of lightly salted RTE meat and seafood products. The experimental work involved samples of ground pork tenderloin, ground chicken breast fillet and skinned, ground salmon fillet adjusted to different WPS% i.e., 3.6 and 5.2 WPS% for pork samples, 2.0, 3.0, 3.5 and 6.0 WPS% for chicken samples and 3.0 and 6.0 WPS% for salmon samples. All samples were inoculated with late-stationary phase L. monocytogenes cultures. For pork samples, a two-strain mixture of a pork isolate (MS22254) and an environmental isolate (MS22246) was applied. For chicken and salmon samples, a seafood isolate (MS22258) and isolate MS22246 was applied as single cultures. Samples were vacuum-packed in sterile bags, immerged in water bath, and held at constant temperatures of 57, 60 and 65 °C for pork samples and 58, 61 and 62.5 °C for chicken and salmon samples. For survivor curves, where at least 3 log10-reduction were obtained, heat tolerance was expressed as decimal reduction times, D-values. D-values were observed to increase with increasing WPS%. The effect of salt on heat tolerance of L. monocytogenes was defined as the relative increase (RI-value) in D-value obtained when salt had been added to the food. The effect of WPS% on RI-values was independent of heating temperatures, foods and strains. For secondary modelling, RI-values were transformed using the natural logarithm, ln(RI) and fitted to a linear model as a function of WPS%. Model validation, with 56 independent values collected from the scientific literature, resulted in bias and accuracy factors of 0.89 and 1.26, respectively, suggesting acceptable performance with tendency to slightly under-predict. The developed predictive model can be used to guide the design of heat processes for manufacturers of lightly preserved and mildly processed meat and seafood products requiring more than 3 log10 reduction of L. monocytogenes to ensure safety.
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Affiliation(s)
- Tina Beck Hansen
- The National Food Institute, Technical University of Denmark, Division for Microbiology and Production, Kemitorvet, Building 202, DK-2800 Kgs. Lyngby, Denmark.
| | - Somaya Abdalas
- The National Food Institute, Technical University of Denmark, Division for Microbiology and Production, Kemitorvet, Building 202, DK-2800 Kgs. Lyngby, Denmark
| | - Iman Al-Hilali
- The National Food Institute, Technical University of Denmark, Division for Microbiology and Production, Kemitorvet, Building 202, DK-2800 Kgs. Lyngby, Denmark
| | - Lisbeth Truelstrup Hansen
- The National Food Institute, Technical University of Denmark, Division for Microbiology and Production, Kemitorvet, Building 202, DK-2800 Kgs. Lyngby, Denmark
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35
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Luo Y, Korza G, DeMarco AM, Kuipers OP, Li YQ, Setlow P. Properties of spores of Bacillus subtilis with or without a transposon that decreases spore germination and increases spore wet heat resistance. J Appl Microbiol 2021; 131:2918-2928. [PMID: 34042237 DOI: 10.1111/jam.15163] [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: 12/28/2020] [Revised: 03/14/2021] [Accepted: 05/03/2021] [Indexed: 01/01/2023]
Abstract
AIMS This work aimed to determine how genes on transposon Tn1546 slow Bacillus subtilis spore germination and increase wet heat resistance, and to clarify the transposon's 3 gene spoVA operon's role in spore properties, since the seven wild-type SpoVA proteins form a channel transporting Ca2+ -dipicolinic acid (DPA) in spore formation and germination. METHODS AND RESULTS Deletion of the wild-type spoVA operon from a strain with Tn1546 gave spores with slightly reduced wet heat resistance but some large decreases in germination rate. Spore water content and CaDPA analyses found no significant differences in contents of either component in spores with different Tn1546 components or lacking the wild-type spoVA operon. CONCLUSIONS This work indicates that the SpoVA channel encoded by Tn1546 functions like the wild-type SpoVA channel in CaDPA uptake into developing spores, but not as well in germination. The essentially identical CaDPA and water contents of spores with and without Tn1546 indicate that low core water content does not cause elevated wet heat resistance of spores with Tn1546. SIGNIFICANCE AND IMPACT OF THE STUDY Since wet heat resistance of spores of Bacillus species poses problems in the food industry, understanding mechanisms of spores' wet heat resistance is of significant applied interest.
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Affiliation(s)
- Y Luo
- Department of Physics, East Carolina University, Greenville, NC, USA.,Laboratory for Biomedical Photonics & Engineering, Life Sciences Institute, Guangxi Medical University, Nanning, Guangxi, P.R. China
| | - G Korza
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - A M DeMarco
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - O P Kuipers
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
| | - Y-Q Li
- Department of Physics, East Carolina University, Greenville, NC, USA.,School of Electronic Engineering, Dongguan University of Technology, Dongguan, Guangdong, P.R. China
| | - P Setlow
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
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36
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Ceylan E, Amezquita A, Anderson N, Betts R, Blayo L, Garces-Vega F, Gkogka E, Harris LJ, McClure P, Winkler A, den Besten HMW. Guidance on validation of lethal control measures for foodborne pathogens in foods. Compr Rev Food Sci Food Saf 2021; 20:2825-2881. [PMID: 33960599 DOI: 10.1111/1541-4337.12746] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 02/03/2021] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
Food manufacturers are required to obtain scientific and technical evidence that a control measure or combination of control measures is capable of reducing a significant hazard to an acceptable level that does not pose a public health risk under normal conditions of distribution and storage. A validation study provides evidence that a control measure is capable of controlling the identified hazard under a worst-case scenario for process and product parameters tested. It also defines the critical parameters that must be controlled, monitored, and verified during processing. This review document is intended as guidance for the food industry to support appropriate validation studies, and aims to limit methodological discrepancies in validation studies that can occur among food safety professionals, consultants, and third-party laboratories. The document describes product and process factors that are essential when designing a validation study, and gives selection criteria for identifying an appropriate target pathogen or surrogate organism for a food product and process validation. Guidance is provided for approaches to evaluate available microbiological data for the target pathogen or surrogate organism in the product type of interest that can serve as part of the weight of evidence to support a validation study. The document intends to help food manufacturers, processors, and food safety professionals to better understand, plan, and perform validation studies by offering an overview of the choices and key technical elements of a validation plan, the necessary preparations including assembling the validation team and establishing prerequisite programs, and the elements of a validation report.
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Affiliation(s)
- Erdogan Ceylan
- Silliker Food Science Center, Merieux NutriSciences, Crete, Illinois, USA
| | - Alejandro Amezquita
- Safety and Environmental Assurance Centre, Unilever R&D Colworth, Sharnbrook, Bedfordshire, UK
| | - Nathan Anderson
- U.S. Food and Drug Administration, Bedford Park, Illinois, USA
| | - Roy Betts
- Campden BRI, Chipping Campden, Gloucestershire, UK
| | - Laurence Blayo
- Société des Produits Nestlé S.A, Nestlé Research, Lausanne, Switzerland
| | | | - Elissavet Gkogka
- Arla R&D, Arla Innovation Centre, Aarhus N, Central Jutland Region, Denmark
| | - Linda J Harris
- Department of Food Science and Technology, University of California, Davis, Davis, California, USA
| | - Peter McClure
- Mondelēz International, Mondelēz R&D UK, Birmingham, UK
| | - Anett Winkler
- Microbiology and Food Safety CoE, Cargill Deutschland GmbH, Krefeld, Germany
| | - Heidy M W den Besten
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
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37
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Quantitative Microbiological Analysis of Artisanal Stretched Cheese Manufacture. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11062680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To evaluate the behavior of the relevant microbial populations during stretched cheese production, quantitative microbiological analysis was performed during the critical steps of the preparation. The obtained data distributions proved statistically significant increases in all indicators, on average by 4.55 ± 0.64 log CFU/g of presumptive lactococci counts, 4.06 ± 0.61 of lactobacilli, 1.53 ± 0.57 log CFU/g of coliforms, 2.42 ± 0.67 log CFU/g of Escherichia coli, 1.53 ± 0.75 log CFU/g of yeasts and molds, and 0.99 ± 0.27 log CFU/g of presumptive Staphylococcus aureus, from the early stage of milk coagulation until curd ripening (0–24 h). The following steaming/stretching process caused reductions in viable counts with the most significant inactivation effect on coliform bacteria, including E. coli (−4.0 ± 1.0 log CFU/g). Total viable counts and yeasts and molds showed 2 and almost 3 log reduction (−2.2 ± 1.1 log CFU/g and −2.6 ± 0.9 log CFU/g), respectively. The lowest decreases in presumptive S. aureus counts were estimated at the level of −1.50 ± 0.64 log CFU/g. The counts of yeasts and molds showed the best indicatory function during the entire storage period of vacuum-packaged cheeses at 6 °C.
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38
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Physical and Chemical Methods for Reduction in Aflatoxin Content of Feed and Food. Toxins (Basel) 2021; 13:toxins13030204. [PMID: 33808964 PMCID: PMC7999035 DOI: 10.3390/toxins13030204] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/25/2022] Open
Abstract
Aflatoxins (AFs) are among the most harmful fungal secondary metabolites imposing serious health risks on both household animals and humans. The more frequent occurrence of aflatoxins in the feed and food chain is clearly foreseeable as a consequence of the extreme weather conditions recorded most recently worldwide. Furthermore, production parameters, such as unadjusted variety use and improper cultural practices, can also increase the incidence of contamination. In current aflatoxin control measures, emphasis is put on prevention including a plethora of pre-harvest methods, introduced to control Aspergillus infestations and to avoid the deleterious effects of aflatoxins on public health. Nevertheless, the continuous evaluation and improvement of post-harvest methods to combat these hazardous secondary metabolites are also required. Already in-use and emerging physical methods, such as pulsed electric fields and other nonthermal treatments as well as interventions with chemical agents such as acids, enzymes, gases, and absorbents in animal husbandry have been demonstrated as effective in reducing mycotoxins in feed and food. Although most of them have no disadvantageous effect either on nutritional properties or food safety, further research is needed to ensure the expected efficacy. Nevertheless, we can envisage the rapid spread of these easy-to-use, cost-effective, and safe post-harvest tools during storage and food processing.
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Isolation, stability, and characteristics of high-pressure superdormant Bacillus subtilis spores. Int J Food Microbiol 2021; 343:109088. [PMID: 33621831 DOI: 10.1016/j.ijfoodmicro.2021.109088] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/15/2020] [Accepted: 01/30/2021] [Indexed: 12/26/2022]
Abstract
Bacterial spores are a major challenge in industrial decontamination processes owing to their extreme resistance. High-pressure (HP) of 150 MPa at 37 °C can trigger the germination of spores, making them lose their extreme resistance. Once their resistance is lost, germinated spores can easily be inactivated by a mild decontamination step. The implementation of this gentle germination-inactivation strategy is hindered by the presence of a subpopulation of so-called high-pressure superdormant (HPSD) spores, which resist germination or germinate only very slowly in response to HP. It is essential to understand the properties of HPSD spores and the underlying causes of superdormancy to tackle superdormant spores and further develop germination-inactivation strategies involving HP. This study investigated factors influencing the prevalence of HPSD spores and successfully isolated them by combining buoyant density centrifugation and fluorescence-activated cell sorting, which allowed further characterisation of HPSD spores for the first time. The prevalence of HPSD spores was shown to be strongly dependent on the HP dwell time, with increasing treatment times reducing their prevalence. Spore mutants lacking major germinant receptors further showed a highly increased prevalence of HPSD spores; 93% of the spores remained dormant even after a prolonged HP dwell time of 40 min. In contrast to nutrient germination, sublethal heat treatment of 75 °C for 30 min prior to pressure treatment did not induce spore activation and increase germination. The isolated HPSD spores did not show visible structural differences compared to the initial dormant spores when investigated with transmission electron microscopy. Re-sporulated HPSD spores showed similar germination capacity compared to the initial dormant spores, indicating that HPSD spores are most likely not genetically different from the rest of the population. Moreover, the majority of HPSD spores germinated when exposed a second time to the same germination treatment; however, the germination capacity was lower than that of the initial population. The fact that the majority of spores lost superdormancy when exposed a second time to the same trigger makes it unlikely that there is one factor that determines whether a spore germinates with a certain HP treatment or not. Instead, it seems possible that there are other reversible or cumulative causes. This study investigated the factors influencing spore HP superdormancy to improve the understanding of HPSD spores with regard to their stability, germination capacity, and potential underlying causes of spore HP superdormancy. This knowledge will contribute to the development of HP-based germination-inactivation strategies for gentle but effective spore control.
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40
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Guan W, Tan L, Liu X, Cui Z, Zheng Y, Yeung KWK, Zheng D, Liang Y, Li Z, Zhu S, Wang X, Wu S. Ultrasonic Interfacial Engineering of Red Phosphorous-Metal for Eradicating MRSA Infection Effectively. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006047. [PMID: 33349987 DOI: 10.1002/adma.202006047] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/11/2020] [Indexed: 05/18/2023]
Abstract
Sonodynamic therapy (SDT) is considered to be a potential treatment for various diseases including cancers and bacterial infections due to its deep penetration ability and biosafety, but its SDT efficiency is limited by the hypoxia environment of deep tissues. This study proposes creating a potential solution, sonothermal therapy, by developing the ultrasonic interfacial engineering of metal-red phosphorus (RP), which has an obviously improved sonothermal ability of more than 20 °C elevation under 25 min of continuous ultrasound (US) excitation as compared to metal alone. The underlying mechanism is that the mechanical energy of the US activates the motion of the interfacial electrons. US-induced electron motion in the RP can efficiently transfer the US energy into phonons in the forms of heat and lattice vibrations, resulting in a stronger US absorption of metal-RP. Unlike the nonspecific heating of the cavitation effect induced by US, titanium-RP can be heated in situ when the US penetrates through 2.5 cm of pork tissue. In addition, through a sonothermal treatment in vivo, bone infection induced by multidrug-resistant Staphylococcus aureus (MRSA) is successfully eliminated in under 20 min of US without tissue damage. This work provides a new strategy for combating MRSA by strong sonothermal therapy through US interfacial engineering.
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Affiliation(s)
- Wei Guan
- Hubei Key Laboratory of Polymer Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering, Hubei University, Wuhan, 430062, China
| | - Lei Tan
- Hubei Key Laboratory of Polymer Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering, Hubei University, Wuhan, 430062, China
| | - Xiangmei Liu
- Hubei Key Laboratory of Polymer Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering, Hubei University, Wuhan, 430062, China
| | - Zhenduo Cui
- School of Materials Science & Engineering, The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, Tianjin University, Tianjin, 300072, China
| | - Yufeng Zheng
- College of Engineering, State Key Laboratory for Turbulence and Complex System, Department of Materials Science and Engineering, Peking University, Beijing, 100871, China
| | - Kelvin Wai Kwok Yeung
- Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, 999077, China
| | - Dong Zheng
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yanqin Liang
- School of Materials Science & Engineering, The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, Tianjin University, Tianjin, 300072, China
| | - Zhaoyang Li
- School of Materials Science & Engineering, The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, Tianjin University, Tianjin, 300072, China
| | - Shengli Zhu
- School of Materials Science & Engineering, The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, Tianjin University, Tianjin, 300072, China
| | - Xianbao Wang
- Hubei Key Laboratory of Polymer Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering, Hubei University, Wuhan, 430062, China
| | - Shuilin Wu
- School of Materials Science & Engineering, The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, Tianjin University, Tianjin, 300072, China
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Mead HL, Hamm PS, Shaffer IN, Teixeira MDM, Wendel CS, Wiederhold NP, Thompson GR, Muñiz-Salazar R, Castañón-Olivares LR, Keim P, Plude C, Terriquez J, Galgiani JN, Orbach MJ, Barker BM. Differential Thermotolerance Adaptation between Species of Coccidioides. J Fungi (Basel) 2020; 6:E366. [PMID: 33327629 PMCID: PMC7765126 DOI: 10.3390/jof6040366] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/24/2020] [Accepted: 12/05/2020] [Indexed: 12/18/2022] Open
Abstract
Coccidioidomycosis, or Valley fever, is caused by two species of dimorphic fungi. Based on molecular phylogenetic evidence, the genus Coccidioides contains two reciprocally monophyletic species: C. immitis and C. posadasii. However, phenotypic variation between species has not been deeply investigated. We therefore explored differences in growth rate under various conditions. A collection of 39 C. posadasii and 46 C. immitis isolates, representing the full geographical range of the two species, was screened for mycelial growth rate at 37 °C and 28 °C on solid media. The radial growth rate was measured for 16 days on yeast extract agar. A linear mixed effect model was used to compare the growth rate of C. posadasii and C. immitis at 37 °C and 28 °C, respectively. C. posadasii grew significantly faster at 37 °C, when compared to C. immitis; whereas both species had similar growth rates at 28 °C. These results indicate thermotolerance differs between these two species. As the ecological niche has not been well-described for Coccidioides spp., and disease variability between species has not been shown, the evolutionary pressure underlying the adaptation is unclear. However, this research reveals the first significant phenotypic difference between the two species that directly applies to ecological research.
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Affiliation(s)
- Heather L. Mead
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA; (H.L.M.); (P.K.)
| | - Paris S. Hamm
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA;
| | - Isaac N. Shaffer
- School of Informatics, Computers, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA;
| | | | | | - Nathan P. Wiederhold
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 77030, USA;
| | - George R. Thompson
- Departments of Internal Medicine Division of Infectious Diseases, and Medical Microbiology and Immunology, University of California-Davis, Sacramento, CA 95616, USA;
| | - Raquel Muñiz-Salazar
- Laboratorio de Epidemiología y Ecología Molecular, Escuela Ciencias de la Salud, Universidad Autónoma de Baja California, Unidad Valle Dorado, Ensenada 22890, Mexico;
| | - Laura Rosio Castañón-Olivares
- Department of Microbiology and Parasitology, Universidad Nacional Autónoma de Mexico, Ciudad de México 04510, Mexico;
| | - Paul Keim
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA; (H.L.M.); (P.K.)
| | - Carmel Plude
- Northern Arizona Healthcare, Flagstaff, AZ 86001, USA; (C.P.); (J.T.)
| | - Joel Terriquez
- Northern Arizona Healthcare, Flagstaff, AZ 86001, USA; (C.P.); (J.T.)
| | - John N. Galgiani
- Valley Fever Center for Excellence, University of Arizona, Tucson, AZ 85721, USA; (J.N.G.); (M.J.O.)
| | - Marc J. Orbach
- Valley Fever Center for Excellence, University of Arizona, Tucson, AZ 85721, USA; (J.N.G.); (M.J.O.)
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Bridget M. Barker
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA; (H.L.M.); (P.K.)
- Valley Fever Center for Excellence, University of Arizona, Tucson, AZ 85721, USA; (J.N.G.); (M.J.O.)
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Zwietering MH, Garre A, den Besten HMW. Incorporating strain variability in the design of heat treatments: A stochastic approach and a kinetic approach. Food Res Int 2020; 139:109973. [PMID: 33509519 DOI: 10.1016/j.foodres.2020.109973] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 09/07/2020] [Accepted: 11/28/2020] [Indexed: 12/26/2022]
Abstract
For the design of thermal processes, the decimal reduction times (D-values) of target organisms can be used. However, many factors influence the D-value, like inherent organism's characteristics (strain variability), the effect of the history of the cells, as well as product factors and process factors. Strain variability is a very large contributor to the overall variation of the D-value. Hence, the overall reduction of microbial contaminants by a heat treatment is a combination of the occurrence of a strain with a certain heat resistance and its reduction given the prevailing conditions. This reduction can be determined using two approaches: a kinetic analysis based on integral equations or a stochastic approach based on Monte Carlo analysis. In this article, these two approaches are compared using as case studies the inactivation of two microorganisms: Listeria monocytogenes in a pasteurization process and the sporeformer Geobacillus stearothermophilus in a UHT process. Both approaches resulted in similar conclusions, highlighting that the strains with the highest heat resistance are determinant for the overall inactivation, even if the probability of cells having such extreme heat resistance is very low.
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Affiliation(s)
- Marcel H Zwietering
- Food Microbiology, Wageningen University, PO Box 17, 6700 AA Wageningen, the Netherlands
| | - Alberto Garre
- Food Microbiology, Wageningen University, PO Box 17, 6700 AA Wageningen, the Netherlands
| | - Heidy M W den Besten
- Food Microbiology, Wageningen University, PO Box 17, 6700 AA Wageningen, the Netherlands.
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43
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Pulsed electric field pre-treatment for enhanced bacterial survival after drying: Effect of carrier matrix and strain variability. INNOV FOOD SCI EMERG 2020. [DOI: 10.1016/j.ifset.2020.102515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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44
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Garre A, Acosta A, Reverte-Orts JD, Periago PM, Díaz-Morcillo A, Esnoz A, Pedreño-Molina JL, Fernández PS. Microbiological and process variability using biological indicators of inactivation (BIIs) based on Bacillus cereus spores of food and fish-based animal by-products to evaluate microwave heating in a pilot plant. Food Res Int 2020; 137:109640. [PMID: 33233219 DOI: 10.1016/j.foodres.2020.109640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 07/31/2020] [Accepted: 08/21/2020] [Indexed: 11/28/2022]
Abstract
Microwave processing can be a valid alternative to conventional heating for different types of products. It enables a more efficient heat transfer in the food matrix, resulting in higher quality products. However, for many food products a uniform temperature distribution is not possible because of heterogeneities in their physical properties and non-uniformtiy in the electric field pattern. Hence, the effectiveness of microwave inactivation treatments is influenced by both intrinsic (differences between cells) and extrinsic variability (non-uniform temperature). Interpreting the results of the process and considering its impact on microbial inactivation is essential to ensure effective and efficient processing. In this work, we quantified the variability in microbial inactivation attained in a microwave pasteurization treatment with a tunnel configuration at pilot-plant scale. The configuration of the equipment makes it impossible to measure the product temperature during treatment. For that reason, variability in microbial counts was measured using Biological Inactivation Indicators (BIIs) based on spherical particles of alginate inoculated with spores of Bacillus spp. The stability of the BIIs and the uncertainty associated to them was assessed using preliminary experiments in a thermoresistometer. Then, they were introduced in the food product to analyse the microbial inactivation in different points of the products during the microwave treatment. Experiments were made in a vegetable soup and a fish-based animal by-product (F-BP). The results show that the variation in the microbial counts was higher than expected based on the biological variability estimated in the thermoresistometer and the uncertainty of the BIIs. This is due to heterogeneities in the temperature field (measured using a thermographic camera), which were higher in the F-BP than in the vegetable soup. Therefore, for the process studied, extrinsic variability was more relevant than intrinsic variability. The methodology presented in this work can be a valid method to evaluate pasteurization treatments of foods processed by heating, providing valuable information of the microbial inactivation achieved. It can contribute to design microwave processes for different types of products and for product optimization.
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Affiliation(s)
- Alberto Garre
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena (ETSIA), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain
| | - Alejandro Acosta
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena (ETSIA), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain
| | - Juan D Reverte-Orts
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena (ETSIT), Plaza del Hospital, 1, 30202 Cartagena, Spain
| | - Paula M Periago
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena (ETSIA), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain
| | - Alejandro Díaz-Morcillo
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena (ETSIT), Plaza del Hospital, 1, 30202 Cartagena, Spain
| | - Arturo Esnoz
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena (ETSIA), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain
| | - Juan L Pedreño-Molina
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena (ETSIT), Plaza del Hospital, 1, 30202 Cartagena, Spain
| | - Pablo S Fernández
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena (ETSIA), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain.
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Impact of shoulders on the calculus of heat sterilization treatments with different bacterial spores. Food Microbiol 2020; 94:103663. [PMID: 33279088 DOI: 10.1016/j.fm.2020.103663] [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: 08/06/2020] [Revised: 10/09/2020] [Accepted: 10/09/2020] [Indexed: 12/28/2022]
Abstract
To date, heat is still the most used technology in food preservation. The calculus of heat treatments is usually based on Bigelow observations i.e. treatment time is an exponential function of the heat treatment temperature. However, a number of researchers have reported deviations from linearity in heat inactivation curves that caused errors in the calculus. This research was designed to evaluate the variability of shoulder length among different sporulated species, the impact of treatment temperature on these shoulders and the relationship between the traditional DT value and shoulder length. The heat inactivation kinetics of five bacterial spores of importance for the food industry was evaluated. B. weihenstephanensis and B. cereus did not show shoulders and DT values calculated ranged from 0.99 to 0.23 and from 1.33 to 0.56 respectively at temperatures from 100 to 102.5 °C. On the other side B. subtilis, B. licheniformis and G. stearothermophilus showed shoulders of 1.75-0.42, 1.92-0.43 and 3.22-0.78 and DT values of 1.52-0.32, 2.12-0.59 and 2.22-0.48 respectively in the range of temperatures tested. From the results obtained it was concluded that the presence and magnitude of shoulders depended on the bacterial spore species, the longest being those on the bacterial spores which showed greatest heat resistance. It has also been proved that shoulder lengths vary with treatment temperature in the same proportion of traditional DT values, with the relationship Sl/DT being constant. Thus, an equation which included the constant Sl/DT was proposed.
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van Boekel MAJS, ter Steeg PF, Dahoe AE. Co-optimization of safety, quality and legislation: opening Pandora’s box? Curr Opin Food Sci 2020. [DOI: 10.1016/j.cofs.2020.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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47
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Torre R, Costa-Rama E, Nouws HPA, Delerue-Matos C. Screen-Printed Electrode-Based Sensors for Food Spoilage Control: Bacteria and Biogenic Amines Detection. BIOSENSORS 2020; 10:E139. [PMID: 33008005 PMCID: PMC7600659 DOI: 10.3390/bios10100139] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 12/31/2022]
Abstract
Food spoilage is caused by the development of microorganisms, biogenic amines, and other harmful substances, which, when consumed, can lead to different health problems. Foodborne diseases can be avoided by assessing the safety and freshness of food along the production and supply chains. The routine methods for food analysis usually involve long analysis times and complex instrumentation and are performed in centralized laboratories. In this context, sensors based on screen-printed electrodes (SPEs) have gained increasing importance because of their advantageous characteristics, such as ease of use and portability, which allow fast analysis in point-of-need scenarios. This review provides a comprehensive overview of SPE-based sensors for the evaluation of food safety and freshness, focusing on the determination of bacteria and biogenic amines. After discussing the characteristics of SPEs as transducers, the main bacteria, and biogenic amines responsible for important and common foodborne diseases are described. Then, SPE-based sensors for the analysis of these bacteria and biogenic amines in food samples are discussed, comparing several parameters, such as limit of detection, analysis time, and sample type.
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Affiliation(s)
- Ricarda Torre
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal; (R.T.); (H.P.A.N.)
| | - Estefanía Costa-Rama
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal; (R.T.); (H.P.A.N.)
- Departamento de Química Física y Analítica, Universidad de Oviedo, Av. Julián Clavería 8, 33006 Oviedo, Spain
| | - Henri P. A. Nouws
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal; (R.T.); (H.P.A.N.)
| | - Cristina Delerue-Matos
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal; (R.T.); (H.P.A.N.)
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48
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Eijlander RT, Breitenwieser F, de Groot R, Hoornstra E, Kamphuis H, Kokken M, Kuijpers A, de Mello IIG, de Rijdt GV, Vadier CÉ, Wells-Bennik MHJ. Enumeration and Identification of Bacterial Spores in Cocoa Powders. J Food Prot 2020; 83:1530-1539. [PMID: 32338739 DOI: 10.4315/jfp-20-071] [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: 02/18/2020] [Accepted: 04/25/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT The presence of bacterial spores in cocoa powders is inevitable due to the cocoa bean fermentation process, during which members of the genera Bacillus and Geobacillus are typically present. Spores are a concern in heat-treated foods when they survive heat treatments and the finished product supports germination, growth, and potentially toxin production. In this study, available methods for the enumeration of total mesophilic and thermophilic spores (TMS and TTS, respectively) were evaluated, leading to the recommendation of one global method specifically for cocoa powders. The proposed method was validated during a ring test on seven selected cocoa powders and applied during routine analyses on commercial powders. The method includes dilution of cocoa powder using buffered peptone water, heating at 80°C for 10 min for TMS and TTS counts, and heating at 100°C for 30 min for a heat-resistant (HR) spore count. Tryptic soy agar is used as a recovery medium with a maximal concentration of cocoa powder of 2.5 mg/mL (to prevent growth inhibition) and a nonnutrient agar overlay to prevent swarming of bacteria. Plates are incubated for at least 72 h at 30°C for recovery of mesophilic bacteria and 55°C for thermophilic bacteria. Suitable alternatives to specific method parameters are provided. Median values of total spore concentrations are low (<400 CFU/g for TMS and <75 CFU/g for TTS), and concentrations of HR spores are very low (<5 CFU/g). Importantly, the relation between concentrations of HR spores in cocoa powder and incidence of spoilage of heat-treated beverages containing cocoa is currently unclear. In the powders included in this study, Bacillus subtilis and Bacillus licheniformis were the predominant spore-forming species identified (49 and 39%, respectively). Both species are known for high variability in spore heat resistance. The development of reliable and sensitive molecular methods is therefore required to assess the risk of spoilage caused by spores present in cocoa powders. HIGHLIGHTS
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Affiliation(s)
- Robyn T Eijlander
- NIZO Food Research, Kernhemseweg 2, 6718 ZB Ede, The Netherlands.,(ORCID: https://orcid.org/0000-0002-4408-6526 [R.T.E.])
| | | | - Rosanne de Groot
- Olam Cocoa BV, Stationsstraat 76, 1541 LJ Koog aan de Zaan, The Netherlands
| | - Erik Hoornstra
- FrieslandCampina, Stationsplein 4, 3818 LE Amersfoort, The Netherlands
| | - Henri Kamphuis
- Cargill Cocoa and Chocolate, Eenhoornweg 12, 1531 ME Wormer, The Netherlands
| | - Michiel Kokken
- Olam Cocoa BV, Stationsstraat 76, 1541 LJ Koog aan de Zaan, The Netherlands
| | | | | | | | - CÉcile Vadier
- Barry Callebaut France, rue de la mécanique, 27400 Louviers, France
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Furtado MM, Silva BS, Faviero C, Alvarenga VO, Sant’Ana AS. Impact of carrier agents and temperature during storage of dry inocula of Salmonella enterica: A contribution to the validation of low water activity foods processing interventions. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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50
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Clemente-Carazo M, Cebrián G, Garre A, Palop A. Variability in the heat resistance of Listeria monocytogenes under dynamic conditions can be more relevant than that evidenced by isothermal treatments. Food Res Int 2020; 137:109538. [PMID: 33233166 DOI: 10.1016/j.foodres.2020.109538] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 10/23/2022]
Abstract
Heterogeneity in the response of microbial cells to environmental conditions is inherent to every biological system and can be very relevant for food safety, potentially being as important as intrinsic and extrinsic factors. However, previous studies analyzing variability in the microbial response to thermal treatments were limited to data obtained under isothermal conditions, whereas in the reality, environmental conditions are dynamic. In this article we analyse both empirically and through mathematical modelling the variability in the microbial response to thermal treatments under isothermal and dynamic conditions. Heat resistance was studied for four strains of Listeria monocytogenes (Scott A, CECT 4031, CECT 4032 and 12MOB052), in three different matrices (buffered peptone water, pH 7 Mcllvaine buffer and semi-skimmed milk). Under isothermal conditions, between-strain and between-media variability had no impact in the heat resistance, whereas it was very relevant for dynamic conditions. Therefore, the differences observed under dynamic conditions can be attributed to the variability in the ability for developing stress acclimation. The highest acclimation was observed in strain CECT 4031 (10-fold increase of the D-value), while the lowest acclimation was observed in strain CECT 4032 (50% increase of the D-value). Concerning the different media, acclimation was higher in buffered peptone water and semi-skimmed milk than in Mcllvaine buffer of pH 7.0. To the knowledge of the authors, this is the first research work that specifically analyses the variability of microbial adaptation processes that take place under dynamic conditions. It highlights that microbial heat resistance under dynamic conditions are sometimes determined by mechanisms that cannot be observed when cells are treated in isothermal conditions (e.g. acclimation) and can also be affected by variability. Consequently, empirical evidence on variability gathered under isothermal conditions should be extrapolated with care for dynamic conditions.
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Affiliation(s)
- Marta Clemente-Carazo
- Dpto. Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Campus de Excelencia Internacional Regional "Campus Mare Nostrum", Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Spain
| | - Guillermo Cebrián
- Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón - IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - Alberto Garre
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700 AA, Wageningen, the Netherlands
| | - Alfredo Palop
- Dpto. Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Campus de Excelencia Internacional Regional "Campus Mare Nostrum", Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Spain.
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