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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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Liang D, Cui X, Li M, Zhu Y, Zhao L, Liu S, Zhao G, Wang N, Ma Y, Xu L. Effects of sporulation conditions on the growth, germination, and resistance of Clostridium perfringens spores. Int J Food Microbiol 2023; 396:110200. [PMID: 37119648 DOI: 10.1016/j.ijfoodmicro.2023.110200] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 03/15/2023] [Accepted: 04/01/2023] [Indexed: 05/01/2023]
Abstract
Clostridium perfringens can form metabolically dormant spores that can survive in meat preservation processes and cause food spoilage and human disease upon germination and outgrowth. The characteristics of spores in food products are closely related to the sporulation environment. To control or inactivate C. perfringens spores in food industry, the effects of sporulation conditions on the spores characteristics should be examined. This study aimed to investigate the effects of temperature (T), pH, and water activity (aw) on the growth, germination, and wet-heat resistance of C. perfringens C1 spores isolated from food product. The results showed that C. perfringens C1 spores produced at T = 37 °C, pH = 8, and aw = 0.997 had the highest sporulation rate and germination efficiency and lowest wet-heat resistance. A further increase in pH and sporulation temperature reduced the spore counts and germination efficiency, but enhanced spores' wet-heat resistance. By using air-drying method and Raman spectroscopy analysis, the water content, composition, and levels of calcium dipicolinic acid, proteins, and nucleic acids in spores produced under different sporulation conditions were determined. The results obtained revealed that sporulation conditions should be carefully considered during food production and processing, thus providing a novel insight into prevention and control of spores in food industry.
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Affiliation(s)
- Dong Liang
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China; International Joint Laboratory of Meat Processing and Safety in Henan province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
| | - Xiaoshuang Cui
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China; International Joint Laboratory of Meat Processing and Safety in Henan province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
| | - Miaoyun Li
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China; International Joint Laboratory of Meat Processing and Safety in Henan province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China.
| | - Yaodi Zhu
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China; International Joint Laboratory of Meat Processing and Safety in Henan province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
| | - Lijun Zhao
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China; International Joint Laboratory of Meat Processing and Safety in Henan province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
| | - Shijie Liu
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China; International Joint Laboratory of Meat Processing and Safety in Henan province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
| | - Gaiming Zhao
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China; International Joint Laboratory of Meat Processing and Safety in Henan province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
| | - Na Wang
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
| | - Yangyang Ma
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China; International Joint Laboratory of Meat Processing and Safety in Henan province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
| | - Lina Xu
- College of Food Science and Technology, International Joint Laboratory of Meat Processing and Safety in Henan Province, Henan Agricultural University, No. 63 Wenhua Rd, Zhengzhou 450002, PR China
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Geobacillus stearothermophilus STCC4517 spore suspensions showed survival curves with shoulder phenomena independent of sporulation temperature and pH, whose duration was an exponential function of treatment temperature. Food Microbiol 2022; 104:103969. [DOI: 10.1016/j.fm.2021.103969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/12/2021] [Accepted: 12/13/2021] [Indexed: 11/23/2022]
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Reineke K, Mathys A. Endospore Inactivation by Emerging Technologies: A Review of Target Structures and Inactivation Mechanisms. Annu Rev Food Sci Technol 2020; 11:255-274. [DOI: 10.1146/annurev-food-032519-051632] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent developments in preservation technologies allow for the delivery of food with nutritional value and superior taste. Of special interest are low-acid, shelf-stable foods in which the complete control or inactivation of bacterial endospores is the crucial step to ensure consumer safety. Relevant preservation methods can be classified into physicochemical or physical hurdles, and the latter can be subclassified into thermal and nonthermal processes. The underlying inactivation mechanisms for each of these physicochemical or physical processes impact different morphological or molecular structures essential for spore germination and integrity in the dormant state. This review provides an overview of distinct endospore defense mechanisms that affect emerging physical hurdles as well as which technologies address these mechanisms. The physical spore-inactivation technologies considered include thermal, dynamic, and isostatic high pressure and electromagnetic technologies, such as pulsed electric fields, UV light, cold atmospheric pressure plasma, and high- or low-energy electron beam.
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Affiliation(s)
| | - Alexander Mathys
- Sustainable Food Processing Laboratory, Department of Health Science and Technology, ETH Zurich, CH-8092 Zurich, Switzerland
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Morimatsu K, Nakaura Y, Inaoka T, Kimura K, Yamamoto K. Effects of Solution pH and Ions on Suicidal Germination of Bacillus subtilis Spores Induced by Medium High Temperature-Medium High Hydrostatic Pressure Treatment. Biocontrol Sci 2020; 24:167-172. [PMID: 31527348 DOI: 10.4265/bio.24.167] [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] [Indexed: 11/01/2022]
Abstract
Spores of Bacillus subtilis suspended in water or aqueous solution of NaCl, CaCl2, sodium lactate, or calcium lactate at pH 4 - 7 was subjected to spore inactivation by simultaneous combination of medium high hydrostatic pressure (MHHP; 100 MPa) treatment for germination and medium high temperature (MHT; 65℃) treatment for pasteurization of germinated vegetative cells. The spores at pH 4 in NaCl solution and those at pH 5 and 6 in Na lactate solutions were less killed than in water by MHHP+MHT treatment. Spore inactivation was promoted by calcium ion in NaCl solution at pH 4 and in Na lactate solutions at pH 5 and pH 6, while it was more suppressed at pH 5 and pH 6 in Na lactate solutions than at pH 4 in NaCl solution. The spores treated by MHHP+MHT in NaCl or Na lactate solution at pH 4 were further killed by subsequent MHT treatment.
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Affiliation(s)
- Kazuya Morimatsu
- Department of Food Production Science, Graduate School of Agriculture, Ehime University
| | - Yoshiko Nakaura
- Food Research Institute, National Agriculture and Food Research Organization
| | - Takashi Inaoka
- Food Research Institute, National Agriculture and Food Research Organization
| | - Keitarou Kimura
- Food Research Institute, National Agriculture and Food Research Organization
| | - Kazutaka Yamamoto
- Food Research Institute, National Agriculture and Food Research Organization
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6
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Schottroff F, Pyatkovskyy T, Reineke K, Setlow P, Sastry SK, Jaeger H. Mechanisms of enhanced bacterial endospore inactivation during sterilization by ohmic heating. Bioelectrochemistry 2019; 130:107338. [PMID: 31377394 DOI: 10.1016/j.bioelechem.2019.107338] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/24/2019] [Accepted: 07/24/2019] [Indexed: 02/06/2023]
Abstract
During ohmic heating, the electric field may additionally inactivate bacterial endospores. However, the exact mechanism of action is unclear. Thus, a mechanistic study was carried out, investigating the possible target of electric fields inside the spore. Bacillus subtilis spores were heated by conventional and ohmic heating in a capillary system under almost identical thermal conditions. Wild-type (PS533) spores were used, as well as isogenic mutants lacking certain components known for their contribution to spores' heat resistance: small-acid soluble proteins (SASP) protecting DNA (PS578); the coat covering the spore (PS3328); and the spore germination enzyme SleB (FB122(+)). Treatment-dependent release of the spore core's depot of dipicolinic acid (DPA) was further evaluated. Up to 2.4 log10 additional inactivation of PS533 could be achieved by ohmic heating, compared to conventional heating. The difference varied for the mutants, with a decreasing difference indicating a decreased effect of the electric field and vice versa. In particular, mutant spores lacking SASPs showed a behavior more similar to thermal inactivation alone. The combination of heat and electric field was shown to be necessary for enhanced spore inactivation. Thus, it is hypothesized that either the heat treatment makes the spore susceptible to the electric field, or vice versa.
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Affiliation(s)
- Felix Schottroff
- Institute of Food Technology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria; Department of Food, Agricultural and Biological Engineering, Ohio State University, Columbus, OH, USA.
| | - Taras Pyatkovskyy
- Department of Food, Agricultural and Biological Engineering, Ohio State University, Columbus, OH, USA
| | | | - Peter Setlow
- Department of Molecular Biology and Biophysics, UCONN Health, Farmington, CT, USA
| | - Sudhir K Sastry
- Department of Food, Agricultural and Biological Engineering, Ohio State University, Columbus, OH, USA
| | - Henry Jaeger
- Institute of Food Technology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
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7
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André S, Leguerinel I, Palop A, Desriac N, Planchon S, Mafart P. Convergence of Bigelow and Arrhenius models over a wide range of heating temperatures. Int J Food Microbiol 2019; 291:173-180. [DOI: 10.1016/j.ijfoodmicro.2018.11.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 10/18/2018] [Accepted: 11/17/2018] [Indexed: 11/30/2022]
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8
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Bressuire-Isoard C, Broussolle V, Carlin F. Sporulation environment influences spore properties in Bacillus: evidence and insights on underlying molecular and physiological mechanisms. FEMS Microbiol Rev 2018; 42:614-626. [DOI: 10.1093/femsre/fuy021] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 05/16/2018] [Indexed: 02/07/2023] Open
Affiliation(s)
- Christelle Bressuire-Isoard
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
| | - Véronique Broussolle
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
| | - Frédéric Carlin
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
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9
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Abbas AA, Planchon S, Jobin M, Schmitt P. Absence of oxygen affects the capacity to sporulate and the spore properties of Bacillus cereus. Food Microbiol 2014; 42:122-31. [DOI: 10.1016/j.fm.2014.03.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 01/28/2014] [Accepted: 03/06/2014] [Indexed: 11/16/2022]
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10
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Abbas AA, Planchon S, Jobin M, Schmitt P. A new chemically defined medium for the growth and sporulation of Bacillus cereus strains in anaerobiosis. J Microbiol Methods 2014; 105:54-8. [PMID: 25019521 DOI: 10.1016/j.mimet.2014.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 07/03/2014] [Accepted: 07/03/2014] [Indexed: 11/19/2022]
Abstract
A new chemically defined liquid medium, MODS, was developed for the aerobic growth and anaerobic growth and sporulation of Bacillus cereus strains. The comparison of sporulation capacity of 18 strains of B. cereus has shown effective growth and spore production in anaerobiosis..
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Affiliation(s)
- Amina Aicha Abbas
- INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, "F-84000 Avignon, France; Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, France
| | - Stella Planchon
- INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, "F-84000 Avignon, France; Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, France
| | - Michel Jobin
- INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, "F-84000 Avignon, France; Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, France
| | - Philippe Schmitt
- INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, "F-84000 Avignon, France; Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, France.
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Sella SRBR, Vandenberghe LPS, Soccol CR. Life cycle and spore resistance of spore-forming Bacillus atrophaeus. Microbiol Res 2014; 169:931-9. [PMID: 24880805 DOI: 10.1016/j.micres.2014.05.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 04/29/2014] [Accepted: 05/04/2014] [Indexed: 12/28/2022]
Abstract
Bacillus endospores have a wide variety of important medical and industrial applications. This is an overview of the fundamental aspects of the life cycle, spore structure and factors that influence the spore resistance of spore-forming Bacillus. Bacillus atrophaeus was used as reference microorganism for this review because their spores are widely used to study spore resistance and morphology. Understanding the mechanisms involved in the cell cycle and spore survival is important for developing strategies for spore killing; producing highly resistant spores for biodefense, food and pharmaceutical applications; and developing new bioactive molecules and methods for spore surface display.
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Affiliation(s)
- Sandra R B R Sella
- Production and Research Centre of Immunobiological Products, Secretaria de Saúde do Estado do Paraná, Piraquara, PR, Brazil; Bioprocess Engineering and Biotechnology Department, Federal University of Paraná, Curitiba, PR, Brazil.
| | - Luciana P S Vandenberghe
- Bioprocess Engineering and Biotechnology Department, Federal University of Paraná, Curitiba, PR, Brazil
| | - Carlos Ricardo Soccol
- Bioprocess Engineering and Biotechnology Department, Federal University of Paraná, Curitiba, PR, Brazil
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Study of the influence of sporulation conditions on heat resistance of Geobacillus stearothermophilus used in the development of biological indicators for steam sterilization. Arch Microbiol 2012; 194:991-9. [PMID: 22872104 DOI: 10.1007/s00203-012-0832-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 07/02/2012] [Accepted: 07/11/2012] [Indexed: 10/28/2022]
Abstract
Biological indicators are important tools in infection control via sterilization process monitoring. The use of a standardized spore crop with a well-defined heat resistance will guarantee the quality of a biological indicator. Ambient factors during sporulation can affect spore characteristics and properties, including heat resistance. The aim of this study is to evaluate the main sporulation factors responsible for heat resistance in Geobacillus stearothermophilus, a useful biological indicator for steam sterilization. A sequence of a three-step optimization of variables (initial pH, nutrient concentration, tryptone, peptone, beef extract, yeast extract, manganese sulfate, magnesium sulfate, calcium chloride and potassium phosphate) was carried out to screen those that have a significant influence on heat resistance of produced spores. The variable exerting greatest influence on G. stearothermophilus heat resistance during sporulation was found to be the initial pH. Lower nutrient concentration and alkaline pH around 8.5 tended to enhance decimal reduction time at 121 °C (D(121°C)). A central composite design enabled a fourfold enhancement in heat resistance, and the model obtained accurately describes positive pH and negative manganese sulfate concentration influence on spore heat resistance.
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13
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Sagarzazu N, Cebrián G, Pagán R, Condón S, Mañas P. Resistance of Campylobacter jejuni to heat and to pulsed electric fields. INNOV FOOD SCI EMERG 2010. [DOI: 10.1016/j.ifset.2010.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Juneja VK, Porto-Fett AC, Call JE, Marks HB, Tamplin ML, Luchansky JB. Thermal inactivation of Bacillus anthracis Sterne in irradiated ground beef heated in a water bath or cooked on commercial grills. INNOV FOOD SCI EMERG 2010. [DOI: 10.1016/j.ifset.2009.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Gounina-Allouane R, Broussolle V, Carlin F. Influence of the sporulation temperature on the impact of the nutrients inosine and l-alanine on Bacillus cereus spore germination. Food Microbiol 2008; 25:202-6. [DOI: 10.1016/j.fm.2007.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 08/23/2007] [Accepted: 08/29/2007] [Indexed: 10/22/2022]
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16
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Faille C, Tauveron G, Le Gentil-Lelièvre C, Slomianny C. Occurrence of Bacillus cereus spores with a damaged exosporium: consequences on the spore adhesion on surfaces of food processing lines. J Food Prot 2007; 70:2346-53. [PMID: 17969617 DOI: 10.4315/0362-028x-70.10.2346] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was designed to evaluate the occurrence of Bacillus cereus spores with a damaged exosporium and the consequences of such damages on spore adhesion. The analysis of nine strains sporulated under optimal conditions (Spo8-agar, 30 degrees C) revealed that damaged exosporia were systematically found in one strain (B. cereus D17) and occasionally in two others (B. cereus ATCC 14579T and B. cereus D6). The prevalence of spores with damaged exosporia increased when sporulation occurred under less favorable conditions (Spo8-broth or high temperature); for example, more than 50% of the B. cereus ATCC 14579T spores were damaged when sporulation occurred at 40 degrees C on Spo8-agar or at 30 degrees C in Spo8-broth. Furthermore, when subjected to shear stresses by circulation of spore suspensions through a peristaltic pump, the exosporium of a significant amount of spores became partially or totally shorn off (for example, 40% of the B. cereus ATCC 14579T spores). The ability of damaged spores to adhere to inert surfaces and to resist cleaning under shear stress was significantly affected when compared with intact spores, resulting in a decreased number of adhering spores (P < or = 0.004) and enhanced resistance to cleaning (P < or = 0.008). This study provides evidence that, under various conditions, the exosporium of B. cereus spores can be partly or wholly damaged, thereby affecting the ability of spores to contaminate the surfaces of food processing lines. The presence of spores devoid of exosporium will be of importance in determining the risk associated with B. cereus spores adherent to food processing line surfaces.
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Affiliation(s)
- C Faille
- INRA-UR638, 369 rue Jules Guesde, BP 20039, F-59651 Villeneuve d'Ascq Cedex, France.
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17
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Mathys A, Heinz V, Schwartz FH, Knorr D. Impact of agglomeration on the quantitative assessment of Bacillus stearothermophilus heat inactivation. J FOOD ENG 2007. [DOI: 10.1016/j.jfoodeng.2006.11.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Novak JS, Call J, Tomasula P, Luchansky JB. An assessment of pasteurization treatment of water, media, and milk with respect to Bacillus spores. J Food Prot 2005; 68:751-7. [PMID: 15830666 DOI: 10.4315/0362-028x-68.4.751] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study evaluated the ability of spore-forming Bacillus spp. to resist milk pasteurization conditions from 72 to 150 degrees C. Spores from the avirulent surrogate Sterne strain of Bacillus anthracis, as well as a representative strain of a common milk contaminant that is also a pathogen, Bacillus cereus ATCC 9818, were heated at test temperatures for up to 90 min in dH2O, brain heart infusion broth, or skim milk. In skim milk, characteristic log reductions (log CFU per milliliter) for B. anthracis spores were 0.45 after 90 min at 72 degrees C, 0.39 after 90 min at 78 degrees C, 8.10 after 60 min at 100 degrees C, 7.74 after 2 min at 130 degrees C, and 7.43 after 0.5 min at 150 degrees C. Likewise, log reductions (log CFU per milliliter) for viable spores of B. cereus ATCC 9818 in skim milk were 0.39 after 90 min at 72 degrees C, 0.21 after 60 min at 78 degrees C, 7.62 after 60 min at 100 degrees C, 7.37 after 2 min at 130 degrees C, and 7.53 after 0.5 min at 150 degrees C. No significant differences (P < 0.05) in thermal resistance were observed for comparisons of spores heated in dH2O or brain heart infusion broth compared with results observed in skim milk for either strain tested. However, spores from both strains were highly resistant (P < 0.05) to the pasteurization temperatures tested. As such, pasteurization alone would not ensure complete inactivation of these spore-forming pathogens in dH2O, synthetic media, or skim milk.
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Affiliation(s)
- John S Novak
- Microbial Food Safety Research Unit, US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19038, USA
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Johnston MD, Lawson S, Otter JA. Evaluation of hydrogen peroxide vapour as a method for the decontamination of surfaces contaminated with Clostridium botulinum spores. J Microbiol Methods 2005; 60:403-11. [PMID: 15649542 DOI: 10.1016/j.mimet.2004.10.021] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 10/15/2004] [Accepted: 10/27/2004] [Indexed: 11/23/2022]
Abstract
The aim of this study was to evaluate the efficacy of hydrogen peroxide vapour (HPV) against spores of Clostridium botulinum, for use as a method for decontaminating environments where this pathogen has been handled. Spores were dried onto stainless steel slides and exposed to HPV in a sealed glovebox enclosure, transferred to a quenching agent at timed intervals during the exposure period, before survivors were cultured and enumerated. D-values were calculated from graphs of log10 survivors plotted against time and were found to range from 1.41 to 4.38 min. HPV was found to be effective at deactivating spores of toxigenic Cl. botulinum, non-toxigenic Clostridium spp. and Geobacillus stearothermophilus dried onto stainless steel surfaces. HPV could be used to decontaminate cabinets and rooms where Cl. botulinum has been handled. The cycle parameters should be based on studies carried out with relevant spores of this organism, rather than based on inactivation data for G. stearothermophilus spores, which have been used in the past as a standard biological challenge for disinfection and sterilisation procedures. HPV could provide an attractive alternative to other decontamination methods, as it was rapid, residue-free and did not give rise to the health and safety concerns associated with other gaseous decontamination systems.
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Affiliation(s)
- M D Johnston
- Department 987, Safety and Environmental Assurance Centre, Unilever Colworth, Sharnbrook, Beds, MK44 1LQ, UK.
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Novak JS, Juneja VK, McClane BA. An ultrastructural comparison of spores from various strains of Clostridium perfringens and correlations with heat resistance parameters. Int J Food Microbiol 2003; 86:239-47. [PMID: 12915035 DOI: 10.1016/s0168-1605(02)00550-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
It has been shown that Clostridium perfringens isolates associated with food poisoning carry a chromosomal cpe gene, whereas nonfood-borne human gastrointestinal disease isolates carry a plasmid cpe gene. In addition, the chromosomal cpe gene isolates exhibit greater heat resistance as compared with the plasmid cpe strains. Therefore, the current study conducted ultrastructural measurements of spores from several plasmid and chromosomal cpe-positive C. perfringens isolates. In support of the dehydration mechanism of spore heat resistance, the C. perfringens spore core average size was found to show a negative correlation with D-values for spores obtained at 100 degrees C. Dipicolinic acid (DPA) concentrations assayed for the spores did not correlate well with C. perfringens spore core averages nor with D(10)-values at 100 degrees C. Spore core thickness might be a distinguishing phenotypic characteristic used to identify heat resistance and survival potential of C. perfringens in improperly cooked foods.
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Affiliation(s)
- J S Novak
- Agriculture Research Service, U.S. Department of Agriculture, Wyndmoor, PA 19038, USA.
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Grow AE, Wood LL, Claycomb JL, Thompson PA. New biochip technology for label-free detection of pathogens and their toxins. J Microbiol Methods 2003; 53:221-33. [PMID: 12654493 DOI: 10.1016/s0167-7012(03)00026-5] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
microSERS is a new biochip technology that uses surface-enhanced Raman scattering (SERS) microscopy for label-free transduction. The biochip itself comprises pixels of capture biomolecules immobilized on a SERS-active metal surface. Once the biochip has been exposed to the sample and the capture biomolecules have selectively bound their ligands, a Raman microscope is used to collect SERS fingerprints from the pixels on the chip. SERS, like other whole-organism fingerprinting techniques, is very specific. Our initial studies have shown that the Gram-positive Listeria and Gram-negative Legionella bacteria, Bacillus spores and Cryptosporidium oocysts can often be identified at the subspecies/strain level on the basis of SERS fingerprints collected from single organisms. Therefore, pathogens can be individually identified by microSERS, even when organisms that cross-react with the capture biomolecules are present in a sample. Moreover, the SERS fingerprint reflects the physiological state of a bacterial cell, e.g., when pathogenic Listeria and Legionella were cultured under conditions known to affect virulence, their SERS fingerprints changed significantly. Similarly, nonviable (e.g., heat- or UV-killed) microorganisms could be differentiated from their viable counterparts by SERS fingerprinting. Finally, microSERS is also capable of the sensitive and highly specific detection of toxins. Toxins that comprised as little as 0.02% by weight of the biomolecule-toxin complex produced strong, unique fingerprints when spectra collected from the complexes were subtracted from the spectra of the uncomplexed biomolecules. For example, aflatoxins B(1) and G(1) could be detected and individually identified when biochips bearing pixels of antibody or enzyme capture biomolecules were incubated in samples containing one or both aflatoxins, and the spectra were then collected for 20 s from an area of the biomolecule pixel approximately 1 microm in diameter. In the future, we plan to investigate the use of hyperspectral imaging Raman microscopy for collecting fingerprints from all the pixels on the biochip, individually yet simultaneously, to enable the rapid detection of diverse pathogens and their toxins in a sample, using a single biochip.
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Affiliation(s)
- Ann E Grow
- Biopraxis, Inc., P.O. Box 910078, San Diego, CA 92191-0078, USA.
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Atrih A, Foster SJ. Analysis of the role of bacterial endospore cortex structure in resistance properties and demonstration of its conservation amongst species. J Appl Microbiol 2001; 91:364-72. [PMID: 11473602 DOI: 10.1046/j.1365-2672.2001.01394.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS The aim of this work was to compare the chemical structure of the spore cortex of a range of species, and to determine any correlation between cortex structure and spore resistance properties. METHODS AND RESULTS The fine chemical structure of the cortex of Bacillus subtilis, Bacillus megaterium, Bacillus cereus and Clostridium botulinum was examined by muropeptide analysis using reverse phase HPLC. There is a conserved basic structure between peptidoglycan of these species, with the only difference being the level of de-N-acetylation of an amino sugar. In order to determine if an alteration in cortex structure correlates with heat resistance properties, the peptidoglycan structure and properties of B. subtilis spores prepared under different conditions were compared. Peptidoglycan from spores prepared in Nutrient Broth (NB) showed reduction in single L-alanine substituted muramic acid to only 13.9% compared with 20.6% in CCY-grown spores. NB-prepared spores are also unstable, with 161-fold less heat resistance (60 min, 85 degrees C) and 43 times less Mn(2+) content than CCY-grown spores. Addition of MnCl(2) to NB led to a peptidoglycan profile similar to CCY-grown spores, sevenfold more heat resistance (60 min, 85 degrees C) and an 86-fold increase in Mn(2+) content. Addition of CCY salts to NB led all parameters to be comparable with CCY-grown spore levels. CONCLUSION It has been shown that peptidoglycan structure is conserved in four spore-forming bacteria. Also, spore heat resistance is multifactorial and cannot be accounted for by any single parameter. SIGNIFICANCE AND IMPACT OF THE STUDY Endospores made by diverse species most likely have common mechanisms of heat resistance. However, the molecular basis for their resistance remains elusive.
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Affiliation(s)
- A Atrih
- Department of Molecular Biology and Biotechnology, University of Sheffield, UK
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Cazemier AE, Wagenaars SF, ter Steeg PF. Effect of sporulation and recovery medium on the heat resistance and amount of injury of spores from spoilage bacilli. J Appl Microbiol 2001; 90:761-70. [PMID: 11348437 DOI: 10.1046/j.1365-2672.2001.01302.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To assess the influence of sporulation media on heat resistance, and the use of stress recovery media to measure preservation injury of spores of five representative spoilage bacilli. METHODS AND RESULTS Bacillus spores prepared on nutrient agar supplemented with Ca2+, Mg2+, Mn2+, Fe2+ and K+ were more heat-resistant than spores obtained from nutrient agar with Mn2+. This increased heat resistance correlated with a decrease in the protoplast water content as determined by buoyant density sedimentation. The degree of preservation injury severity could be assessed on media containing NaCl at moderate pH and organic acids at acid pH. Ca-DPA, K+ or proline were added to the recovery media to demonstrate that heat probably caused injury to both spore germination and the outgrowth system. SIGNIFICANCE AND IMPACT OF THE STUDY The metal content of sporulation media can strongly effect the validity of preservation resistance studies. The distinctive recovery media developed here can be relevant for assessing and comparing new preservation technologies.
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Affiliation(s)
- A E Cazemier
- Microbiology & Preservation, Unilever Research Vlaardingen, Vlaardingen, The Netherlands
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Wuytack EY, Michiels CW. A study on the effects of high pressure and heat on Bacillus subtilis spores at low pH. Int J Food Microbiol 2001; 64:333-41. [PMID: 11294355 DOI: 10.1016/s0168-1605(00)00478-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bacillus subtilis spore suspensions were subjected to pressure treatments at 100 and 600 MPa at 40 degrees C and over a pH range from 3 to 8. Inactivation of spores under these conditions was maximally 80% and was not increased at low pH. However, higher levels of inactivation were obtained when spores were first pressure treated at neutral pH and then exposed for 1 h to low pH. This large difference in inactivation could be explained by the finding that pressure-induced spore germination, which is known to occur at neutral pH, was inhibited at low pH (< 5). Pressure treatment at low pH made spores more sensitive to heat inactivation, suggesting that demineralized H-spores had been formed. Changes in spore core hydration and pH upon exposure of spores at low pH were studied in a more direct way using green fluorescent protein expressed in recombinant B. subtilis as a reporter protein, and it was confirmed that pressure and heat increase spore permeability for protons. Based on these results, the potential of low temperature, high pressure processes for spore inactivation in acid products is discussed.
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Affiliation(s)
- E Y Wuytack
- Laboratory of Food Microbiology, Katholieke Universiteit Leuven, Belgium
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