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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] [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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Potential Risk of Botulinum Neurotoxin -producing Clostridia Occurrence in Canned Fish. J Vet Res 2022; 66:605-611. [PMID: 36846039 PMCID: PMC9945006 DOI: 10.2478/jvetres-2022-0060] [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: 06/03/2022] [Accepted: 10/21/2022] [Indexed: 11/11/2022] Open
Abstract
Introduction Heat treatment is indispensable in fish canning to provide an acceptable shelf life. Its optimisation reduces the risk of the presence of Clostridium botulinum spores, which could potentially cause botulism cases. This study evaluated canned fish samples for botulism neurotoxin (BoNT)-producing clostridia contamination and can bulging through microbiological contaminant growth. A new analytical approach was developed for detection of such clostridia and phenotypically similar species. Material and Methods A total of 70 canned fish samples suspected of exhibiting bulging features were analysed. Culture methods were used to detect clostridia. The isolates obtained were evaluated on the basis of the exhibited phenotypic characteristics. Also, PCRs were used for the detection of genes determining BoNT production (non-toxic non-haemagglutinin (ntnh) genes) and the amplification of conservative 16S rDNA genes, which were Sanger sequenced. The obtained sequences were analysed using the Basic Local Alignment Search Tool. Results Clostridium genus species were isolated from 17 (24%) bulging and organoleptically changed samples. No ntnh genes were present in these isolates; however, sequencing confirmed the presence of C. sporogenes, a species with close affinity to C. botulinum. Conclusion To eliminate the threat of foodborne botulism, laboratory diagnostic techniques must detect species of the Clostridium genus and elucidate their ability to produce BoNTs. Although Clostridium botulinum is the most common cause of botulism, the possibility may not be ignored that non-pathogenic Clostridium species may acquire botulinum toxigenicity. The similarity between the isolated strains of C. sporogenes and C. botulinum should be incorporated in the optimisation of heat treatment to guarantee a sterilised, microbiologically safe product.
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Hyperspectral imaging and deep learning for quantification of Clostridium sporogenes spores in food products using 1D- convolutional neural networks and random forest model. Food Res Int 2021; 147:110577. [PMID: 34399549 DOI: 10.1016/j.foodres.2021.110577] [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: 11/26/2020] [Revised: 06/24/2021] [Accepted: 06/27/2021] [Indexed: 11/23/2022]
Abstract
Clostridium sporogenes spores are used as surrogates for Clostridium botulinum, to verify thermal exposure and lethality in sterilization regimes by food industries. Conventional methods to detect spores are time-consuming and labour intensive. The objectives of this study were to evaluate the feasibility of using hyperspectral imaging (HSI) and deep learning approaches, firstly to identify dead and live forms of C. sporogenes spores and secondly, to estimate the concentration of spores on culture media plates and ready-to-eat mashed potato (food matrix). C. sporogenes spores were inoculated by either spread plating or drop plating on sheep blood agar (SBA) and tryptic soy agar (TSA) plates and by spread plating on the surface of mashed potato. Reflectance in the spectral range of 547-1701 nm from the region of interest was used for principal component analysis (PCA). PCA was successful in distinguishing dead and live spores and different levels of inoculum (102 to 106 CFU/ml) on both TSA and SBA plates, however, was not efficient on the mashed potato (food matrix). Hence, deep learning classification frameworks namely 1D- convolutional neural networks (CNN) and random forest (RF) model were used. CNN model outperformed the RF model and the accuracy for quantification of spores was improved by 4% and 8% in the presence and absence, respectively of dead spores. The screening system used in this study was a combination of HSI and deep learning modelling, which resulted in an overall accuracy of 90-94% when the dead/inactivated spores were present and absent, respectively. The only discrepancy detected was during the prediction of samples with low inoculum levels (<102 CFU/ml). In summary, it was evident that HSI in combination with a deep learning approach showed immense potential as a tool to detect and quantify spores on nutrient media as well as on specific food matrix (mashed potato). However, the presence of dead spores in any sample is postulated to affect the accuracy and would need replicates and confirmatory assays.
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Guo C, Wang Y, Luan D. Non-thermal effects of microwave processing on inactivation of Clostridium Sporogenes inoculated in salmon fillets. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109861] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cramm MA, Chakraborty A, Li C, Ruff SE, Jørgensen BB, Hubert CRJ. Freezing Tolerance of Thermophilic Bacterial Endospores in Marine Sediments. Front Microbiol 2019; 10:945. [PMID: 31130935 PMCID: PMC6509201 DOI: 10.3389/fmicb.2019.00945] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 04/15/2019] [Indexed: 01/18/2023] Open
Abstract
Dormant endospores of anaerobic, thermophilic bacteria found in cold marine sediments offer a useful model for studying microbial biogeography, dispersal, and survival. The dormant endospore phenotype confers resistance to unfavorable environmental conditions, allowing dispersal to be isolated and studied independently of other factors such as environmental selection. To study the resilience of thermospores to conditions relevant for survival in extreme cold conditions, their viability following different freezing treatments was tested. Marine sediment was frozen at either −80°C or −20°C for 10 days prior to pasteurization and incubation at +50°C for 21 days to assess thermospore viability. Sulfate reduction commenced at +50°C following both freezing pretreatments indicating persistence of thermophilic endospores of sulfate-reducing bacteria. The onset of sulfate reduction at +50°C was delayed in −80°C pretreated microcosms, which exhibited more variability between triplicates, compared to −20°C pretreated microcosms and parallel controls that were not frozen in advance. Microbial communities were evaluated by 16S rRNA gene amplicon sequencing, revealing an increase in the relative sequence abundance of thermophilic endospore-forming Firmicutes in all microcosms. Different freezing pretreatments (−80°C and −20°C) did not appreciably influence the shift in overall bacterial community composition that occurred during the +50°C incubations. Communities that had been frozen prior to +50°C incubation showed an increase in the relative sequence abundance of operational taxonomic units (OTUs) affiliated with the class Bacilli, relative to unfrozen controls. These results show that freezing impacts but does not obliterate thermospore populations and their ability to germinate and grow under appropriate conditions. Indeed the majority of the thermospore OTUs detected in this study (21 of 22) could be observed following one or both freezing treatments. These results are important for assessing thermospore viability in frozen samples and following cold exposure such as the very low temperatures that would be encountered during panspermia.
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Affiliation(s)
- Margaret A Cramm
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Anirban Chakraborty
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Carmen Li
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - S Emil Ruff
- Energy Bioengineering Group, Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Bo Barker Jørgensen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Casey R J Hubert
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
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Sinnelä MT, Park YK, Lee JH, Jeong KC, Kim YW, Hwang HJ, Mah JH. Effects of Calcium and Manganese on Sporulation of Bacillus Species Involved in Food Poisoning and Spoilage. Foods 2019; 8:foods8040119. [PMID: 30959957 PMCID: PMC6517867 DOI: 10.3390/foods8040119] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/04/2019] [Accepted: 04/05/2019] [Indexed: 11/16/2022] Open
Abstract
Spores are resistant against many extreme conditions including the disinfection and sterilization methods used in the food industry. Selective prevention of sporulation of Bacillus species is an ongoing challenge for food scientists and fermentation technologists. This study was conducted to evaluate the effects of single and combined supplementation of calcium and manganese on sporulation of common pathogenic and food spoilage Bacillus species: B. cereus, B. licheniformis, B. subtilis and B. coagulans. Sporulation of Bacillus vegetative cells was induced on sporulation media supplemented with diverse concentrations of the minerals. Under the various mineral supplementation conditions, the degree of sporulation was quantified with colonies formed by the Bacillus spores. The results revealed that B. licheniformis and B. cereus displayed the weakest sporulation capabilities on media with minimal supplementation levels of calcium and manganese. The lowest sporulation of B. subtilis and B. coagulans was observed on media supplemented with the highest level of calcium and low levels of manganese. Depending on effect of supplementation on sporulation, the Bacillus species were divided into two distinct groups: B. licheniformis and B. cereus; and B. subtilis and B. coagulans. The information provides valuable insight to selectively reduce sporulation of Bacillus species undesirable in the food industry.
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Affiliation(s)
- Martti Tapani Sinnelä
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Korea.
| | - Young Kyoung Park
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Korea.
| | - Jae Hoan Lee
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Korea.
| | - KwangCheol Casey Jeong
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA.
| | - Young-Wan Kim
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Korea.
| | - Han-Joon Hwang
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Korea.
| | - Jae-Hyung Mah
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Korea.
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Evaluation of growth and sporulation of a non-toxigenic strain of Clostridioides difficile (Z31) and its shelf viability. Braz J Microbiol 2019; 50:263-269. [PMID: 30637658 DOI: 10.1007/s42770-018-0023-4] [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: 02/16/2018] [Accepted: 08/07/2018] [Indexed: 10/27/2022] Open
Abstract
The oral administration of non-toxigenic strains of Clostridioides difficile (NTCD) is currently showing promising results for the prevention of Clostridioides difficile infection (CDI) in humans and animals, and is being considered as a possible commercial product to be used in the near future. The aim of this work was to evaluate five culture media for the growth and sporulation of one NTCD (Z31) and evaluate the viability of a lyophilized spore solution of NTCD Z31 stored at 4 °C or at 25 °C for 2 years. Reinforced clostridial medium (RCM) and brain heart infusion broth (BHI) provided the highest production of NTCD Z31 spores. In the first 6 months of the storage of the lyophilized solution, a reduction in spore count of approximately 0.3 Log10 CFU/mL was observed; however, no further significant reduction in spore count was observed up to 24 months. No difference in spore concentration was found between the two storage temperatures from 6 to 24 months of storage. The present work showed BHI and RCM to be the best choices for the growth and sporulation of NTCD Z31 and suggested that the spores of NTCD Z31 are stable for up to 2 years under both temperature conditions.
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Huang L. Growth of non-toxigenic Clostridium botulinum mutant LNT01 in cooked beef: One-step kinetic analysis and comparison with C. sporogenes and C. perfringens. Food Res Int 2018; 107:248-256. [DOI: 10.1016/j.foodres.2018.02.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/08/2018] [Accepted: 02/11/2018] [Indexed: 12/01/2022]
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9
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Oliveira RB, Lopes LS, Baptista RC, Chincha AA, Portela JB, Nascimento JS, Costa LE, Cruz AG, Sant’Ana AS. Occurrence, populations, diversity, and growth potential of spore-forming bacteria in “requeijão cremoso”. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2017.10.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Oliveira RB, Baptista RC, Chincha AA, Conceição DA, Nascimento JS, Costa LE, Cruz AG, Sant’Ana AS. Thermal inactivation kinetics of Paenibacillus sanguinis 2301083PRC and Clostridium sporogenes JCM1416MGA in full and low fat “requeijão cremoso”. Food Control 2018. [DOI: 10.1016/j.foodcont.2017.08.030] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Rodriguez C, Warszawski N, Korsak N, Taminiau B, Van Broeck J, Delmée M, Daube G. Laboratory identification of anaerobic bacteria isolated on Clostridium difficile selective medium. Acta Microbiol Immunol Hung 2016; 63:171-84. [PMID: 27352971 DOI: 10.1556/030.63.2016.2.3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite increasing interest in the bacterium, the methodology for Clostridium difficile recovery has not yet been standardized. Cycloserine-cefoxitin fructose taurocholate (CCFT) has historically been the most used medium for C. difficile isolation from human, animal, environmental, and food samples, and presumptive identification is usually based on colony morphologies. However, CCFT is not totally selective. This study describes the recovery of 24 bacteria species belonging to 10 different genera other than C. difficile, present in the environment and foods of a retirement establishment that were not inhibited in the C. difficile selective medium. These findings provide insight for further environmental and food studies as well as for the isolation of C. difficile on supplemented CCFT.
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Affiliation(s)
- Cristina Rodriguez
- Food Science Department, FARAH, Faculty of Veterinary Medicine, University of Liège , Liège, Belgium
| | - Nathalie Warszawski
- Food Science Department, FARAH, Faculty of Veterinary Medicine, University of Liège , Liège, Belgium
| | - Nicolas Korsak
- Food Science Department, FARAH, Faculty of Veterinary Medicine, University of Liège , Liège, Belgium
| | - Bernard Taminiau
- Food Science Department, FARAH, Faculty of Veterinary Medicine, University of Liège , Liège, Belgium
| | - Johan Van Broeck
- Belgian Reference Centre for Clostridium difficile (NRC), Pôle de microbiologiemédicale, UniversitéCatholique de Louvain , Brussels, Belgium
| | - Michel Delmée
- Belgian Reference Centre for Clostridium difficile (NRC), Pôle de microbiologiemédicale, UniversitéCatholique de Louvain , Brussels, Belgium
| | - Georges Daube
- Food Science Department, FARAH, Faculty of Veterinary Medicine, University of Liège , Liège, Belgium
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Abstract
Spores of various Bacillus and Clostridium species are among the most resistant life forms known. Since the spores of some species are causative agents of much food spoilage, food poisoning, and human disease, and the spores of Bacillus anthracis are a major bioweapon, there is much interest in the mechanisms of spore resistance and how these spores can be killed. This article will discuss the factors involved in spore resistance to agents such as wet and dry heat, desiccation, UV and γ-radiation, enzymes that hydrolyze bacterial cell walls, and a variety of toxic chemicals, including genotoxic agents, oxidizing agents, aldehydes, acid, and alkali. These resistance factors include the outer layers of the spore, such as the thick proteinaceous coat that detoxifies reactive chemicals; the relatively impermeable inner spore membrane that restricts access of toxic chemicals to the spore core containing the spore's DNA and most enzymes; the low water content and high level of dipicolinic acid in the spore core that protect core macromolecules from the effects of heat and desiccation; the saturation of spore DNA with a novel group of proteins that protect the DNA against heat, genotoxic chemicals, and radiation; and the repair of radiation damage to DNA when spores germinate and return to life. Despite their extreme resistance, spores can be killed, including by damage to DNA, crucial spore proteins, the spore's inner membrane, and one or more components of the spore germination apparatus.
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Hong YK, Huang L, Yoon WB. Mathematical modeling and growth kinetics of Clostridium sporogenes in cooked beef. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.08.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Microwave is an effective means to deliver energy to food through polymeric package materials, offering potential for developing short-time in-package sterilization and pasteurization processes. The complex physics related to microwave propagation and microwave heating require special attention to the design of process systems and development of thermal processes in compliance with regulatory requirements for food safety. This article describes the basic microwave properties relevant to heating uniformity and system design, and provides a historical overview on the development of microwave-assisted thermal sterilization (MATS) and pasteurization systems in research laboratories and used in food plants. It presents recent activities on the development of 915 MHz single-mode MATS technology, the procedures leading to regulatory acceptance, and sensory results of the processed products. The article discusses needs for further efforts to bridge remaining knowledge gaps and facilitate transfer of academic research to industrial implementation.
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Affiliation(s)
- Juming Tang
- Dept., of Biological Systems Engineering, Washington State UnivPullman, WA, 509-335-2140, U.S.A
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Diao MM, André S, Membré JM. Meta-analysis of D-values of proteolytic Clostridium botulinum and its surrogate strain Clostridium sporogenes PA 3679. Int J Food Microbiol 2014; 174:23-30. [PMID: 24448274 DOI: 10.1016/j.ijfoodmicro.2013.12.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 12/17/2013] [Accepted: 12/29/2013] [Indexed: 11/17/2022]
Abstract
Foodborne botulism is a serious disease resulting from ingestion of preformed Clostridium botulinum neurotoxin in foodstuff. Since the 19th century, the heat resistance of this spore forming bacteria has been extensively studied in order to guarantee the public health associated with low acidic, ambient stable products. The most largely used heat resistance parameters in thermal settings of such products are the D121.1°C values (time required to have a 10-fold decrease of the spore count, at 121.1°C) and the z-values (temperature increase to have a 10-fold decrease of D-values). To determine D121.1°C and z-values of proteolytic C. botulinum and its nontoxigenic surrogate strain C. sporogenes PA3679, a dataset of 911 D-values was collected from 38 scientific studies. Within a meta-analysis framework, a mixed-effect linear model was developed with the log D-value (min) as response and the heat treatment temperature as explicative variable. The studies (38), the C. botulinum strains (11), and the heat treatment media (liquid media and various food matrices, split into nine categories in total) were considered as co-variables having a random effect. The species (C. botulinum and C. sporogenes) and the pH (five categories) were considered as co-variables having a fixed effect. Overall, the model gave satisfactory results with a residual standard deviation of 0.22. The heat resistance of proteolytic C. botulinum was found significantly lower than the C. sporogenes PA 3679 one: the mean D-values at the reference temperature of 121.1°C, in liquid media and pH neutral, were estimated to 0.19 and 1.28min for C. botulinum and C. sporogenes, respectively. On the other hand, the mean z-values of the two species were similar: 11.3 and 11.1°C for C. botulinum and C. sporogenes, respectively. These results will be applied to thermal settings of low-acid ambient stable products.
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Affiliation(s)
- Mamadou Moctar Diao
- INRA, UMR1014 Secalim, 44322 Nantes Cedex 3, France; LUNAM Université, Oniris, Nantes, France
| | - Stéphane André
- CTCPA, Unité de microbiologie, ZA de l'aéroport, 84911 Avignon, France
| | - Jeanne-Marie Membré
- INRA, UMR1014 Secalim, 44322 Nantes Cedex 3, France; LUNAM Université, Oniris, Nantes, France.
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Peng J, Mah JH, Somavat R, Mohamed H, Sastry S, Tang J. Thermal inactivation kinetics of Bacillus coagulans spores in tomato juice. J Food Prot 2012; 75:1236-42. [PMID: 22980006 DOI: 10.4315/0362-028x.jfp-11-490] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The thermal characteristics of the spores and vegetative cells of three strains of Bacillus coagulans (ATCC 8038, ATCC 7050, and 185A) in tomato juice were evaluated. B. coagulans ATCC 8038 was chosen as the target microorganism for thermal processing of tomato products due to its spores having the highest thermal resistance among the three strains. The thermal inactivation kinetics of B. coagulans ATCC 8038 spores in tomato juice between 95 and 115°C were determined independently in two different laboratories using two different heating setups. The results obtained from both laboratories were in general agreement, with z-values (z-value is defined as the change in temperature required for a 10-fold reduction of the D-value, which is defined as the time required at a certain temperature for a 1-log reduction of the target microorganisms) of 8.3 and 8.7°C, respectively. The z-value of B. coagulans 185A spores in tomato juice (pH 4.3) was found to be 10.2°C. The influence of environmental factors, including cold storage time, pH, and preconditioning, upon the thermal resistance of these bacterial spores is discussed. The results obtained showed that a storage temperature of 4°C was appropriate for maintaining the viability and thermal resistance of B. coagulans ATCC 8038 spores. Acidifying the pH of tomato juice decreased the thermal resistance of these spores. A 1-h exposure at room temperature was considered optimal for preconditioning B. coagulans ATCC 8038 spores in tomato juice.
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Affiliation(s)
- Jing Peng
- Department of Biological Systems Engineering, Washington State University, Pullman, WA 99163, USA
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Jesús-Pérez NM, Lapizco-Encinas BH. Dielectrophoretic monitoring of microorganisms in environmental applications. Electrophoresis 2011; 32:2331-57. [PMID: 21823133 DOI: 10.1002/elps.201100107] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 04/14/2011] [Accepted: 04/15/2011] [Indexed: 12/28/2022]
Affiliation(s)
- Nadia M Jesús-Pérez
- Centro de Investigación y de Estudios Avanzados del IPN Unidad Monterrey, Apodaca, Nuevo Leon, México
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