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Wang X, Zheng J, Luo L, Hong Y, Li X, Zhu Y, Wu Y, Bai L. Thermal inactivation kinetics of Listeria monocytogenes in milk under isothermal and dynamic conditions. Food Res Int 2024; 179:114010. [PMID: 38342535 DOI: 10.1016/j.foodres.2024.114010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 02/13/2024]
Abstract
Thermal processing is a widely used method to ensure the microbiological safety of milk. Predictive microbiology plays a crucial role in quantifying microbial growth and decline, providing valuable guidance on the design and optimization of food processing operations. This study aimed to investigate the thermal inactivation kinetics of Listeria monocytogenes in milk under both isothermal and dynamic conditions. The thermal inactivation of L. monocytogenes was conducted under isothermal and non-isothermal conditions in sterilized and pasteurized milk, with and without background microbiota, respectively. Furthermore, a secondary model was developed between the shoulder effect and temperature, which was then integrated into the dynamic model. The results showed that L. monocytogenes grown in Tryptic Soy Yeast Extract Broth (TSBYE) prior to thermal inactivation exhibited higher heat resistance compared to cells grown in sterilized milk at isothermal temperatures of 60.0, 62.5, and 65℃. Moreover, the presence of background microbiota in milk significantly enhanced the heat resistance of L. monocytogenes, as evidenced by the increased D-values from 1.13 min to 2.34 min, from 0.46 min to 0.53 min, and from 0.25 min to 0.34 min at 60.0, 62.5, and 65 °C, respectively, regardless of whether the background microbiota was inactivated after co-growth or co-inactivated with L. monocytogenes. For non-isothermal inactivation, the one-step dynamic model based on the log-linear with shoulder model effectively described the microbial inactivation curve and exhibited satisfactory model performance. The model developed contributes to improved risk assessment, enabling dairy processors to optimize thermal treatment and ensure microbiological safety.
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Affiliation(s)
- Xiang Wang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Jiaming Zheng
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Linyin Luo
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yi Hong
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Xiaofeng Li
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yuqi Zhu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yufan Wu
- Centre of Analysis and Test, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Li Bai
- Key Laboratory of Food Safety Risk Assessment, National Health Commission of the People's Republic of China, China National Center for Food Safety Risk Assessment, Beijing 100022, China.
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2
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González-Tejedor GA, Garre A, Iguaz A, Wong-Zhang R, Fernández PS, Possas A. Dynamic Thermal Treatments in Green Coconut Water Induce Dynamic Stress Adaptation of Listeria innocua That Increases Its Thermal Resistance. Foods 2023; 12:4015. [PMID: 37959134 PMCID: PMC10650898 DOI: 10.3390/foods12214015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/23/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
The global coconut water market is projected to grow in the upcoming years, attributed to its numerous health benefits. However, due to its susceptibility to microbial contamination and the limitations of non-thermal decontamination methods, thermal treatments remain the primary approach to ensure the shelf-life stability and the microbiological safety of the product. In this study, the thermal inactivation of Listeria innocua, a Listeria monocytogenes surrogate, was evaluated in coconut water and in tryptone soy broth (TSB) under both isothermal (50-60 °C) and dynamic conditions (from 30 to 60 °C, with temperature increases of 0.5, 1 and 5 °C/min). Mathematical models were used to analyse the inactivation data. The Geeraerd model effectively described the thermal inactivation of L. innocua in both TSB and coconut water under isothermal conditions, with close agreement between experimental data and model fits. Parameter estimates and analysis revealed that acidified TSB is a suitable surrogate medium for studying the thermal inactivation of L. innocua in coconut water, despite minor differences observed in the shoulder length of inactivation curves, likely attributed to the media composition. The models fitted to the data obtained at isothermal conditions fail to predict L. innocua responses under dynamic conditions. This is attributed to the stress acclimation phenomenon that takes place under dynamic conditions, where bacterial cells adapt to initial sub-lethal treatment stages, leading to increased thermal resistance. Fitting the Bigelow model directly to dynamic data with fixed z-values reveals a three-fold increase in D-values with lower heating rates, supporting the role of stress acclimation. The findings of this study aid in designing pasteurization treatments targeting L. innocua in coconut water and enable the establishment of safe, mild heat treatments for refrigerated, high-quality coconut water.
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Affiliation(s)
- Gerardo A. González-Tejedor
- Sistema Nacional de Investigación (SNI), Senacyt, Ciudad de Panamá, Panama;
- Centro de Producción e Investigaciones Agroindustriales, Universidad Tecnológica de Panamá, Ciudad de Panamá, Panama;
| | - Alberto Garre
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain; (A.G.); (A.I.)
| | - Asunción Iguaz
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain; (A.G.); (A.I.)
| | - Ricardo Wong-Zhang
- Centro de Producción e Investigaciones Agroindustriales, Universidad Tecnológica de Panamá, Ciudad de Panamá, Panama;
| | - Pablo S. Fernández
- Departamento de Ingeniería Agronómica, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain; (A.G.); (A.I.)
| | - Arícia Possas
- Department of Food Science and Technology, UIC Zoonosis y Enfermedades Emergentes ENZOEM, CeiA3, Universidad de Córdoba, 14014 Córdoba, Spain
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Bodea IM, Cătunescu GM, Palop Gómez A, Fernández Escámez PS, Garre Perez A. Training in tools to develop quantitative microbial risk assessment of ready-to-eat food with a comparison between the Romanian and Spanish food supply chains. EFSA J 2023; 21:e211006. [PMID: 38047124 PMCID: PMC10687766 DOI: 10.2903/j.efsa.2023.e211006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023] Open
Abstract
The prevention and control of bacterial contamination on ready-to-eat (RTE) fresh produce is an essential task to ensure food safety. Therefore, the development of novel and effective decontamination technologies to ensure microbiological safety of fruits and vegetables has gained considerable attention and new sanitisation methods are needed. The antimicrobial activity of essential oils (EOs) is well documented, but their application in fresh produce remains a challenge due to their hydrophobic nature. Thus, nanoemulsions efficiently contribute to support the use of EOs in foods by enhancing their dispersibility, their contact area and facilitating the introduction into bacterial cells. The combination of these factors ultimately increases their antimicrobial activity. Quantitative microbial risk assessment (QMRA) is gaining more attention as an effective tool to assess and prevent potential risks associated with food-borne pathogens. In this context, the current project aims to study the effectiveness of different washing methods based on nanoemulsified EOs, comparing them against traditional methods, using a QMRA model for Escherichia coli O157:H7 on cherry tomatoes. Different simulations within a stochastic risk assessment model were implemented using the biorisk package for R, aiming to describe microbial behaviour and biological risk along the Romanian and Spanish food supply chains of RTE fresh produce. Nanoemulsions were prepared using oregano and rosemary EOs, each from Romania and Spain. The four nanoemulsions were evaluated as decontamination treatments to control the growth of E. coli O157:H7 on artificially contaminated cherry tomatoes. The decontamination treatments showed encouraging results, comparable to commonly used chlorine solutions. Therefore, oregano and rosemary nanoemulsions are promising and could be a feasible alternative for chlorine solutions in the reduction of microbiological contaminants.
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Affiliation(s)
- Ioana M Bodea
- Department of Technical and Soil Sciences, Faculty of AgricultureUniversity of Agricultural Science and Veterinary Medicine Cluj‐Napoca400372Cluj‐NapocaRomania
| | - Giorgiana M Cătunescu
- Department of Technical and Soil Sciences, Faculty of AgricultureUniversity of Agricultural Science and Veterinary Medicine Cluj‐Napoca400372Cluj‐NapocaRomania
| | - Alfredo Palop Gómez
- Departamento de Ingeniería AgronómicaETSIA‐Universidad Politécnica de CartagenaPaseo Alfonso XIII, 4830203CartagenaSpain
| | - Pablo S Fernández Escámez
- Departamento de Ingeniería AgronómicaETSIA‐Universidad Politécnica de CartagenaPaseo Alfonso XIII, 4830203CartagenaSpain
| | - Alberto Garre Perez
- Departamento de Ingeniería AgronómicaETSIA‐Universidad Politécnica de CartagenaPaseo Alfonso XIII, 4830203CartagenaSpain
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4
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Georgalis L, Yeak KYC, Tsimpou C, Fernandez PS, Wells-Bennik M, Garre A. Disentangling the contributions of initial heterogeneities and dynamic stress adaptation to nonlinearities in bacterial survival curves. Food Res Int 2023; 173:113385. [PMID: 37803723 DOI: 10.1016/j.foodres.2023.113385] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 10/08/2023]
Abstract
The deviations from log-linearity that are often observed in bacterial survivor curves can be explained using different arguments, both biological and experimental. In this study, we used Bacillus subtilis as a model organism to demonstrate that the generally accepted vitalistic arguments (initial heterogeneities in the stress resistance of the cells in the population) may fail to describe microbial inactivation in some situations. In this sense, we showed how dynamic stress acclimation during an isothermal treatment provides an alternative explanation for survivor curves with an upwards curvature. We also provided an innovative experimental approach based on preadaptation experiments to evaluate which hypothesis is more suitable for the bacterial response. Furthermore, we used our experimental results to define bounds for the possible stress acclimation that may take place during dynamic treatments, concluding that the magnitude of stress acclimation may be larger for dynamic treatments than for isothermal experiments. We also evaluated the contribution of the SigB general stress response system to heat resistance by comparing the heat survival of wt and the ΔsigB mutant. Both strains survived better in 51, 52.5 and 55 °C when cells were pre-adapted at 48 °C than non-pre-adapted cells. However, ΔsigB was less resistant to heat than wt due to the missing SigB general stress system. Although these conclusions were based on B. subtilis as a model organism, this study can be the first step towards the development of a novel methodology able to estimate dynamic effects using only isothermal experiments. This would improve the models developed within the predictive microbiology community, improving our ability to predict microbial inactivation during industrial treatments, which are most often dynamic.
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Affiliation(s)
- Leonidas Georgalis
- Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain
| | - Kah Yen Claire Yeak
- NIZO, Kernhemseweg 2, 6718 ZB Ede, the Netherlands; Food Microbiology, Wageningen University and Research, 6700 EV Wageningen, the Netherlands
| | - Christina Tsimpou
- Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain
| | - Pablo S Fernandez
- Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain
| | | | - Alberto Garre
- Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain.
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5
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Garre A, den Besten HM, Fernandez PS, Zwietering MH. Response to letter to the Editor from M. Peleg on: Not just variability and uncertainty; the relevance of chance for the survival of microbial cells to stress. Trends Food Sci Technol 2022. [DOI: 10.1016/j.tifs.2022.01.017] [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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6
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Clemente-Carazo M, Leal JJ, Huertas JP, Garre A, Palop A, Periago PM. The Different Response to an Acid Shock of Two Salmonella Strains Marks Their Resistance to Thermal Treatments. Front Microbiol 2021; 12:691248. [PMID: 34616373 PMCID: PMC8488367 DOI: 10.3389/fmicb.2021.691248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 08/18/2021] [Indexed: 11/13/2022] Open
Abstract
Microbial cells respond to sub-lethal stresses with several physiological changes to increase their chance of survival. These changes are of high relevance when combined treatments (hurdle technology) are applied during food production, as the cells surviving the first hurdle may have greater resistance to subsequent treatments than untreated cells. In this study, we analyzed if Salmonella develops increased resistance to thermal treatments after the application of an acid shock. We compared the heat resistance of acid-shocked (pH 4.5 achieved with citric acid) Salmonella cells with that of cells maintained at pH 7 (control cells). Thermal treatments were performed between 57.5 and 65°C. We observed a differential response between the two strains studied. Acid-shocked cells of Salmonella Senftenberg exhibited reduced heat resistance, e.g., for a treatment at 60.0°C and pH 7.0 the time required to reduce the population by 3 log cycles was lowered from 10.75 to 1.98min with respect to control cells. Salmonella Enteritidis showed a different response, with acid-shocked cells having similar resistance than untreated cells (the time required to reduce 3 log cycles at 60.0°C and pH 7.0 was 0.30min for control and 0.31min for acid-shock cells). Based on results by differential plating (with or without adding the maximum non-inhibitory concentration of NaCl to the recovery medium), we hypothesize that the differential response between strains can be associated to sub-lethal damage to the cell membrane of S. Senftenberg caused by the acid shock. These results provide evidence that different strains of the same species can respond differently to an acid shock and highlight the relevance of cross-resistances for microbial risk assessment.
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Affiliation(s)
- Marta Clemente-Carazo
- Departamento Ingeniería Agronómica, Campus de Excelencia Internacional Regional "Campus Mare Nostrum", Instituto de Biotecnología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
| | - José-Juan Leal
- Departamento Ingeniería Agronómica, Campus de Excelencia Internacional Regional "Campus Mare Nostrum", Instituto de Biotecnología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
| | - Juan-Pablo Huertas
- Departamento Ingeniería Agronómica, Campus de Excelencia Internacional Regional "Campus Mare Nostrum", Instituto de Biotecnología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
| | - Alberto Garre
- Food Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Alfredo Palop
- Departamento Ingeniería Agronómica, Campus de Excelencia Internacional Regional "Campus Mare Nostrum", Instituto de Biotecnología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
| | - Paula M Periago
- Departamento Ingeniería Agronómica, Campus de Excelencia Internacional Regional "Campus Mare Nostrum", Instituto de Biotecnología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
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7
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Impact of Heating Rates on Alicyclobacillus acidoterrestris Heat Resistance under Non-Isothermal Treatments and Use of Mathematical Modelling to Optimize Orange Juice Processing. Foods 2021; 10:foods10071496. [PMID: 34203239 PMCID: PMC8304110 DOI: 10.3390/foods10071496] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/14/2021] [Accepted: 06/19/2021] [Indexed: 12/25/2022] Open
Abstract
Alicyclobacillus acidoterrestris is a spoilage microorganism responsible for relevant product and economic losses in the beverage and juice industry. Spores of this microorganism can survive industrial heat treatments and cause spoilage during posterior storage. Therefore, an effective design of processing treatments requires an accurate understanding of the heat resistance of this microorganism. Considering that industrial treatments are dynamic; this understanding must include how the heat resistance of the microorganism is affected by the heating rate during the heating and cooling phases. The main objective of this study was to establish the effect of heating rates and complex thermal treatments on the inactivation kinetics of A. acidoterrestris. Isothermal experiments between 90 and 105 °C were carried out in a Mastia thermoresistometer, as well as four different dynamic treatments. Although most of the inactivation takes place during the holding phase, our results indicate the relevance of the heating phase for the effectiveness of the treatment. The thermal resistance of A. acidoterrestris is affected by the heating rate during the heating phase. Specifically, higher heating rates resulted in an increased microbial inactivation with respect to the one predicted based on isothermal experiments. These results provide novel information regarding the heat response of this microorganism, which can be valuable for the design of effective heat treatments to improve product safety and stability. Moreover, it highlights the need to incorporate experimental data based on dynamic treatments in process design, as heating rates can have a very significant effect on the thermal resistance of microorganisms.
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8
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Liu Y, Dong Q, Wang X, Liu B, Yuan S. Analysis and probabilistic simulation of
Listeria monocytogenes
inactivation in cooked beef during unsteady heating. Int J Food Sci Technol 2021. [DOI: 10.1111/ijfs.14849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Yangtai Liu
- University of Shanghai for Science and Technology Shanghai200093China
| | - Qingli Dong
- University of Shanghai for Science and Technology Shanghai200093China
| | - Xiang Wang
- University of Shanghai for Science and Technology Shanghai200093China
| | - Baolin Liu
- University of Shanghai for Science and Technology Shanghai200093China
| | - Sanling Yuan
- University of Shanghai for Science and Technology Shanghai200093China
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9
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Georgalis L, Garre A, Fernandez Escamez PS. Training in tools to develop Quantitative Risk Assessment using Spanish ready-to-eat food examples. EFSA J 2020; 18:e181103. [PMID: 33294042 PMCID: PMC7691611 DOI: 10.2903/j.efsa.2020.e181103] [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] [Indexed: 11/18/2022] Open
Abstract
Unsafe food poses global health threats, potentially endangering consumers. The great majority of people will experience a food-borne disease at some point in their lives. Ready-to-eat (RTE) food is the one intended by the producer or the manufacturer for direct human consumption without the need for cooking or other processing effective to eliminate or reduce the concentration of pathogenic microorganisms. Prepared foods are often complex and may contain multiple components that make them vulnerable for growth of pathogenic microorganisms. Among all the pathogenic microorganisms that may be present in RTE foods, Listeria monocytogenes is of special interest because it is the causative agent of listeriosis and it has the ability to survive and replicate at refrigeration and low pH conditions. We performed a quantitative microbial risk assessment (QMRA) in RTE dry-fermented sausage to measure the risk of listeriosis associated to the consumption of this product. The starting point of our investigation was the storage at the factory, after the end-product was produced and before distribution to retail. The stochastic model was implemented in MicroHibro, an online tool for QMRA. Because L. monocytogenes concentration and prevalence can vary greatly between different studies and different types of fermented sausages, we tested different scenarios to show the importance of low prevalence and concentration of the pathogen at the final product. Our results show that the risk estimates are very sensitive to the modelling hypotheses used to describe this process. Therefore, the development of accurate probabilistic models describing the initial concentration of L. monocytogenes shall largely reduce the uncertainty associated to the QMRA of listeriosis in this type of product.
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10
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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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11
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Velasco-Hernández A, Saucedo-Veloz C, Ramírez-Guzmán ME, Chávez-Franco SH, Valle-Guadarrama S, Saucedo-Reyes D. Effect of moderate thermal treatments on the inactivation of a strain of Listeria monocytogenes and physicochemical properties of soursop pulp. FOOD SCI TECHNOL INT 2020; 26:535-548. [PMID: 32223432 DOI: 10.1177/1082013220913357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Soursop (Annona muricata L.) is a commercially important tropical fruit, whether fresh or processed as a pasteurized or frozen pulp used to prepare juice, drinks, nectar, ice cream, popsicles, and desserts. Besides preserving quality, another preoccupation in the processing of fruit pulps is product safety. Several studies show the association between pulp processing and the development of various microorganisms; however, few have focused on the association between L. monocytogenes and the pulp of sour fruits. The objective was to evaluate the effect of moderate thermal treatments on the inactivation of L. monocytogenes and the physicochemical properties in soursop pulp in order to determine the best processing conditions that will allow to maintain quality as well as to achieve an adequate level of safety. Thermal inactivation kinetics were obtained for L. monocytogenes inoculated in soursop pulp at five levels of temperature (50, 52.5, 55, 57.5, and 60 ℃) and different exposure times (0-60 min). The survival curves did not suggest a log-linear relationship, and were, consequently, fitted to the modified Gompertz equation. The results indicated that the modified Gompertz equation provided an acceptable goodness of fit. Five-log10 cycles reductions of L. monocytogenes were achieved at 50 ℃/60 min, 52.5 ℃/16 min, 55 ℃/10 min, 57.5 ℃/5 min, and 60 ℃/1.25 min. These 5-log10 treatments applied to the soursop pulp indicated that the soursop pulp showed changes in the color parameters and a decrease in the content of total sugars, reducing sugars, ascorbic acid, total phenols, and pH.
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12
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Garre A, Espín JF, Huertas JP, Periago PM, Palop A. Limonene nanoemulsified with soya lecithin reduces the intensity of non-isothermal treatments for inactivation of Listeria monocytogenes. Sci Rep 2020; 10:3656. [PMID: 32107438 PMCID: PMC7046608 DOI: 10.1038/s41598-020-60571-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 02/13/2020] [Indexed: 11/18/2022] Open
Abstract
Consumers' demands for ready-to-eat, fresh-like products are on the rise during the last years. This type of products have minimal processing conditions that can enable the survival and replication of pathogenic microorganisms. Among them, Listeria monocytogenes is of special concern, due to its relatively high mortality rate and its ability to replicate under refrigeration conditions. Previous research works have shown that nanoemulsified essential oils in combination with thermal treatments are effective for inactivating L. monocytogenes. However, previous research works were limited to isothermal conditions, whereas actual processing conditions in industry are dynamic. Under dynamic conditions, microorganism can respond unexpectedly to the thermal stress (e.g. adaptation, acclimation or increased sensitivity). In this work, we assess the combination of nanoemulsified D-limonene with thermal treatments under isothermal and dynamic conditions. The nanoemulsion was prepared following an innovative methodology using soya lecithin, a natural compound as well as the essential oil. Under isothermal heating conditions, the addition of the antimicrobial enables a reduction of the treatment time by a factor of 25. For time-varying treatments, dynamic effects were relevant. Treatments with a high heating rate (20 °C/min) are more effective than those with a slow heating rate (1 °C/min). This investigation demonstrates that the addition of nanoemulsified D-limonene can greatly reduce the intensity of the thermal treatments currently applied in the food industry. Hence, it can improve the product quality without impacting its safety.
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Affiliation(s)
- Alberto Garre
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700 AA, Wageningen, The Netherlands
| | - Jennifer F Espín
- 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, Cartagena, Spain
| | - Juan-Pablo Huertas
- 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, Cartagena, Spain
| | - Paula M Periago
- 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, Cartagena, Spain
| | - 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, Cartagena, Spain.
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