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Susanti D, Volland A, Tawari N, Baxter N, Gangaiah D, Plata G, Nagireddy A, Hawkins T, Mane SP, Kumar A. Multi-Omics Characterization of Host-Derived Bacillus spp. Probiotics for Improved Growth Performance in Poultry. Front Microbiol 2021; 12:747845. [PMID: 34745051 PMCID: PMC8563996 DOI: 10.3389/fmicb.2021.747845] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/24/2021] [Indexed: 01/04/2023] Open
Abstract
Microbial feed ingredients or probiotics have been used widely in the poultry industry to improve production efficiency. Spore-forming Bacillus spp. offer advantages over traditional probiotic strains as Bacillus spores are resilient to high temperature, acidic pH, and desiccation. This results in increased strain viability during manufacturing and feed-pelleting processes, extended product shelf-life, and increased stability within the animal’s gastrointestinal tract. Despite numerous reports on the use of Bacillus spores as feed additives, detailed characterizations of Bacillus probiotic strains are typically not published. Insufficient characterizations can lead to misidentification of probiotic strains in product labels, and the potential application of strains carrying virulence factors, toxins, antibiotic resistance, or toxic metabolites. Hence, it is critical to characterize in detail the genomic and phenotypic properties of these strains to screen out undesirable properties and to tie individual traits to clinical outcomes and possible mechanisms. Here, we report a screening workflow and comprehensive multi-omics characterization of Bacillus spp. for use in broiler chickens. Host-derived Bacillus strains were isolated and screened for desirable probiotic properties. The phenotypic, genomic and metabolomic analyses of three probiotic candidates, two Bacillus amyloliquefaciens (Ba ATCC PTA126784 and ATCC PTA126785), and a Bacillus subtilis (Bs ATCC PTA126786), showed that all three strains had promising probiotic traits and safety profiles. Inclusion of Ba ATCC PTA12684 (Ba-PTA84) in the feed of broiler chickens resulted in improved growth performance, as shown by a significantly improved feed conversion ratio (3.3%), increased of European Broiler Index (6.2%), and increased average daily gain (ADG) (3.5%). Comparison of the cecal microbiomes from Ba PTA84-treated and control animals suggested minimal differences in microbiome structure, indicating that the observed growth promotion presumably was not mediated by modulation of cecal microbiome.
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Affiliation(s)
- Dwi Susanti
- Division of Discovery Biology, Bacteriology and Microbiome, Elanco Animal Health, Greenfield, IN, United States
| | - Alyssa Volland
- Division of Discovery Biology, Bacteriology and Microbiome, Elanco Animal Health, Greenfield, IN, United States
| | - Nilesh Tawari
- Division of Global Computational Sciences, Elanco Animal Health, Greenfield, IN, United States
| | - Nielson Baxter
- Division of Nutritional Health, Elanco Animal Health, Greenfield, IN, United States
| | - Dharanesh Gangaiah
- Division of Discovery Biology, Bacteriology and Microbiome, Elanco Animal Health, Greenfield, IN, United States
| | - Germán Plata
- Division of Global Computational Sciences, Elanco Animal Health, Greenfield, IN, United States
| | - Akshitha Nagireddy
- Division of Global Computational Sciences, Elanco Animal Health, Greenfield, IN, United States
| | - Troy Hawkins
- Division of Global Computational Sciences, Elanco Animal Health, Greenfield, IN, United States
| | - Shrinivasrao P Mane
- Division of Global Computational Sciences, Elanco Animal Health, Greenfield, IN, United States
| | - Arvind Kumar
- Division of Discovery Biology, Bacteriology and Microbiome, Elanco Animal Health, Greenfield, IN, United States
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Tu Z, Setlow P, Brul S, Kramer G. Molecular Physiological Characterization of a High Heat Resistant Spore Forming Bacillus subtilis Food Isolate. Microorganisms 2021; 9:667. [PMID: 33807113 PMCID: PMC8005191 DOI: 10.3390/microorganisms9030667] [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: 03/01/2021] [Revised: 03/18/2021] [Accepted: 03/20/2021] [Indexed: 02/07/2023] Open
Abstract
Bacterial endospores (spores) are among the most resistant living forms on earth. Spores of Bacillus subtilis A163 show extremely high resistance to wet heat compared to spores of laboratory strains. In this study, we found that spores of B. subtilis A163 were indeed very wet heat resistant and released dipicolinic acid (DPA) very slowly during heat treatment. We also determined the proteome of vegetative cells and spores of B. subtilis A163 and the differences in these proteomes from those of the laboratory strain PY79, spores of which are much less heat resistant. This proteomic characterization identified 2011 proteins in spores and 1901 proteins in vegetative cells of B. subtilis A163. Surprisingly, spore morphogenic protein SpoVM had no homologs in B. subtilis A163. Comparing protein expression between these two strains uncovered 108 proteins that were differentially present in spores and 93 proteins differentially present in cells. In addition, five of the seven proteins on an operon in strain A163, which is thought to be primarily responsible for this strain's spores high heat resistance, were also identified. These findings reveal proteomic differences of the two strains exhibiting different resistance to heat and form a basis for further mechanistic analysis of the high heat resistance of B. subtilis A163 spores.
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Affiliation(s)
- Zhiwei Tu
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UCONN Health, Farmington, CT 06030-3303, USA;
| | - Stanley Brul
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
| | - Gertjan Kramer
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
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Investigating Synthesis of the MalS Malic Enzyme during Bacillus subtilis Spore Germination and Outgrowth and the Influence of Spore Maturation and Sporulation Conditions. mSphere 2020; 5:5/4/e00464-20. [PMID: 32759333 PMCID: PMC7407067 DOI: 10.1128/msphere.00464-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The spores formed by Bacillus subtilis remain in a quiescent state for extended periods due to their dormancy and resistance features. Dormancy is linked to a very low level of core water content and a phase-bright state of spores. The present report, focusing on proteins MalS and PdhD (pyruvate dehydrogenase subunit D) and complementary to our companion report published in this issue, aims to shed light on a major dilemma in the field, i.e., whether protein synthesis, in particular that of MalS, takes place in phase-bright spores. Clustered MalS-GFP in dormant spores diffuses throughout the spore as germination proceeds. However, fluorescence intensity measurements, supported by Western blot analysis and SILAC proteomics, confirm that there is no new MalS protein synthesis in bright-phase dormant spores. Spore-forming bacteria of the orders Bacillales and Clostridiales play a major role in food spoilage and foodborne diseases. When environmental conditions become favorable, these spores can germinate as the germinant receptors located on the spore’s inner membrane are activated via germinant binding. This leads to the formation of vegetative cells via germination and subsequent outgrowth and potential deleterious effects on foods. The present report focuses on analysis of the synthesis of the MalS (malic enzyme) protein during Bacillus subtilis spore germination by investigating the dynamics of the presence and fluorescence level of a MalS-GFP (MalS-green fluorescent protein) fusion protein using time-lapse fluorescence microscopy. Our results show an initial increase in MalS-GFP fluorescence intensity within the first 15 min of germination, followed by a discernible drop and stabilization of the fluorescence throughout spore outgrowth as reported previously (L. Sinai, A. Rosenberg, Y. Smith, E. Segev, and S. Ben-Yehuda, Mol Cell 57:695–707, 2015, https://doi.org/10.1016/j.molcel.2014.12.019). However, in contrast to the earlier report, both Western blotting and SILAC (stable isotopic labeling of amino acids in cell culture) analysis showed there was no increase in MalS-GFP levels during the 15 min after the addition of germinants and that MalS synthesis did not begin until more than 90 min after germinant addition. Thus, the increase in MalS-GFP fluorescence early in germination is not due to new protein synthesis but is perhaps due to a change in the physical environment of the spore cores. Our findings also show that different sporulation conditions and spore maturation times affect expression of MalS-GFP and the germination behavior of the spores, albeit to a minor extent, but still result in no changes in MalS-GFP levels early in spore germination. IMPORTANCE The spores formed by Bacillus subtilis remain in a quiescent state for extended periods due to their dormancy and resistance features. Dormancy is linked to a very low level of core water content and a phase-bright state of spores. The present report, focusing on proteins MalS and PdhD (pyruvate dehydrogenase subunit D) and complementary to our companion report published in this issue, aims to shed light on a major dilemma in the field, i.e., whether protein synthesis, in particular that of MalS, takes place in phase-bright spores. Clustered MalS-GFP in dormant spores diffuses throughout the spore as germination proceeds. However, fluorescence intensity measurements, supported by Western blot analysis and SILAC proteomics, confirm that there is no new MalS protein synthesis in bright-phase dormant spores.
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4
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SYBR Green Real-Time PCR Assay for Detection of the Indicator Bacillus cereus to Validate Thermal Processing of Tender Coconut Water. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2019. [DOI: 10.22207/jpam.13.3.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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5
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Trunet C, Carlin F, Coroller L. Investigating germination and outgrowth of bacterial spores at several scales. Trends Food Sci Technol 2017. [DOI: 10.1016/j.tifs.2017.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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6
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Jamroskovic J, Chromikova Z, List C, Bartova B, Barak I, Bernier-Latmani R. Variability in DPA and Calcium Content in the Spores of Clostridium Species. Front Microbiol 2016; 7:1791. [PMID: 27891119 PMCID: PMC5104732 DOI: 10.3389/fmicb.2016.01791] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/25/2016] [Indexed: 01/31/2023] Open
Abstract
Spores of a number of clostridial species, and their resistance to thermal treatment is a major concern for the food industry. Spore resistance to wet heat is related to the level of spore hydration, which is inversely correlated with the content of calcium and dipicolinic acid (DPA) in the spore core. It is widely believed that the accumulation of DPA and calcium in the spore core is a fundamental component of the sporulation process for all endospore forming species. We have noticed heterogeneity in the heat resistance capacity and overall DPA/calcium content among the spores of several species belonging to Clostridium sensu stricto group: two C. acetobutylicum strains (DSM 792 and 1731), two C. beijerinckii strains (DSM 791 and NCIMB 8052), and a C. collagenovorans strain (DSM 3089). A C. beijerinckii strain (DSM 791) and a C. acetobutylicum strain (DSM 792) display low Ca and DPA levels. In addition, these two species, with the lowest average Ca/DPA content amongst the strains considered, also exhibit minimal heat resistance. There appears to be no correlation between the Ca/DPA content and the phylogenetic distribution of the C. acetobutylicum and C. beijerinckii species based either on the 16S rRNA or the spoVA gene. This finding suggests that a subset of Clostridium sensu stricto species produce spores with low resistance to wet heat. Additionally, analysis of individual spores using STEM-EDS and STXM revealed that DPA and calcium levels can also vary amongst individual spores in a single spore population.
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Affiliation(s)
- Jan Jamroskovic
- Swiss Federal Institute of Technology in Lausanne (EPFL)Lausanne, Switzerland; Institute of Molecular Biology, Slovak Academy of SciencesBratislava, Slovakia
| | - Zuzana Chromikova
- Institute of Molecular Biology, Slovak Academy of Sciences Bratislava, Slovakia
| | - Cornelia List
- Swiss Federal Institute of Technology in Lausanne (EPFL) Lausanne, Switzerland
| | - Barbora Bartova
- Swiss Federal Institute of Technology in Lausanne (EPFL) Lausanne, Switzerland
| | - Imrich Barak
- Institute of Molecular Biology, Slovak Academy of Sciences Bratislava, Slovakia
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Berendsen EM, Boekhorst J, Kuipers OP, Wells-Bennik MHJ. A mobile genetic element profoundly increases heat resistance of bacterial spores. ISME JOURNAL 2016; 10:2633-2642. [PMID: 27105070 DOI: 10.1038/ismej.2016.59] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 02/25/2016] [Accepted: 02/29/2016] [Indexed: 01/05/2023]
Abstract
Bacterial endospores are among the most resilient forms of life on earth and are intrinsically resistant to extreme environments and antimicrobial treatments. Their resilience is explained by unique cellular structures formed by a complex developmental process often initiated in response to nutrient deprivation. Although the macromolecular structures of spores from different bacterial species are similar, their resistance to environmental insults differs widely. It is not known which of the factors attributed to spore resistance confer very high-level heat resistance. Here, we provide conclusive evidence that in Bacillus subtilis, this is due to the presence of a mobile genetic element (Tn1546-like) carrying five predicted operons, one of which contains genes that encode homologs of SpoVAC, SpoVAD and SpoVAEb and four other genes encoding proteins with unknown functions. This operon, named spoVA2mob, confers high-level heat resistance to spores. Deletion of spoVA2mob in a B. subtilis strain carrying Tn1546 renders heat-sensitive spores while transfer of spoVA2mob into B. subtilis 168 yields highly heat-resistant spores. On the basis of the genetic conservation of different spoVA operons among spore-forming species of Bacillaceae, we propose an evolutionary scenario for the emergence of extremely heat-resistant spores in B. subtilis, B. licheniformis and B. amyloliquefaciens. This discovery opens up avenues for improved detection and control of spore-forming bacteria able to produce highly heat-resistant spores.
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Affiliation(s)
- Erwin M Berendsen
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands.,University of Groningen, Laboratory of Molecular Genetics, Groningen, The Netherlands.,NIZO Food Research B.V., Ede, The Netherlands
| | - Jos Boekhorst
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands.,NIZO Food Research B.V., Ede, The Netherlands
| | - Oscar P Kuipers
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands.,University of Groningen, Laboratory of Molecular Genetics, Groningen, The Netherlands
| | - Marjon H J Wells-Bennik
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands.,NIZO Food Research B.V., Ede, The Netherlands
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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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9
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Study of the combined effect of electro-activated solutions and heat treatment on the destruction of spores of Clostridium sporogenes and Geobacillus stearothermophilus in model solution and vegetable puree. Anaerobe 2015; 35:11-21. [DOI: 10.1016/j.anaerobe.2015.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/08/2015] [Accepted: 06/14/2015] [Indexed: 11/22/2022]
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Bacillus thermoamylovorans Spores with Very-High-Level Heat Resistance Germinate Poorly in Rich Medium despite the Presence of ger Clusters but Efficiently upon Exposure to Calcium-Dipicolinic Acid. Appl Environ Microbiol 2015; 81:7791-801. [PMID: 26341201 DOI: 10.1128/aem.01993-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/26/2015] [Indexed: 11/20/2022] Open
Abstract
High-level heat resistance of spores of Bacillus thermoamylovorans poses challenges to the food industry, as industrial sterilization processes may not inactivate such spores, resulting in food spoilage upon germination and outgrowth. In this study, the germination and heat resistance properties of spores of four food-spoiling isolates were determined. Flow cytometry counts of spores were much higher than their counts on rich medium (maximum, 5%). Microscopic analysis revealed inefficient nutrient-induced germination of spores of all four isolates despite the presence of most known germination-related genes, including two operons encoding nutrient germinant receptors (GRs), in their genomes. In contrast, exposure to nonnutrient germinant calcium-dipicolinic acid (Ca-DPA) resulted in efficient (50 to 98%) spore germination. All four strains harbored cwlJ and gerQ genes, which are known to be essential for Ca-DPA-induced germination in Bacillus subtilis. When determining spore survival upon heating, low viable counts can be due to spore inactivation and an inability to germinate. To dissect these two phenomena, the recoveries of spores upon heat treatment were determined on plates with and without preexposure to Ca-DPA. The high-level heat resistance of spores as observed in this study (D120°C, 1.9 ± 0.2 and 1.3 ± 0.1 min; z value, 12.2 ± 1.8°C) is in line with survival of sterilization processes in the food industry. The recovery of B. thermoamylovorans spores can be improved via nonnutrient germination, thereby avoiding gross underestimation of their levels in food ingredients.
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12
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Madslien EH, Olsen JS, Granum PE, Blatny JM. Genotyping of B. licheniformis based on a novel multi-locus sequence typing (MLST) scheme. BMC Microbiol 2012; 12:230. [PMID: 23051848 PMCID: PMC3492095 DOI: 10.1186/1471-2180-12-230] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 09/14/2012] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Bacillus licheniformis has for many years been used in the industrial production of enzymes, antibiotics and detergents. However, as a producer of dormant heat-resistant endospores B. licheniformis might contaminate semi-preserved foods. The aim of this study was to establish a robust and novel genotyping scheme for B. licheniformis in order to reveal the evolutionary history of 53 strains of this species. Furthermore, the genotyping scheme was also investigated for its use to detect food-contaminating strains. RESULTS A multi-locus sequence typing (MLST) scheme, based on the sequence of six house-keeping genes (adk, ccpA, recF, rpoB, spo0A and sucC) of 53 B. licheniformis strains from different sources was established. The result of the MLST analysis supported previous findings of two different subgroups (lineages) within this species, named "A" and "B" Statistical analysis of the MLST data indicated a higher rate of recombination within group "A". Food isolates were widely dispersed in the MLST tree and could not be distinguished from the other strains. However, the food contaminating strain B. licheniformis NVH1032, represented by a unique sequence type (ST8), was distantly related to all other strains. CONCLUSIONS In this study, a novel and robust genotyping scheme for B. licheniformis was established, separating the species into two subgroups. This scheme could be used for further studies of evolution and population genetics in B. licheniformis.
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Affiliation(s)
- Elisabeth H Madslien
- Forsvarets Forskningsinstitutt FFI, Norwegian Defence Research Establishment, P. O. Box 25, Kjeller, N-2027, Norway
- Department of Food Safety and Infection Biology, Section for Food Safety, Norwegian School of Veterinary Science, P. O. Box 8146 Dep, Oslo, N-0033, Norway
| | - Jaran S Olsen
- Forsvarets Forskningsinstitutt FFI, Norwegian Defence Research Establishment, P. O. Box 25, Kjeller, N-2027, Norway
| | - Per E Granum
- Department of Food Safety and Infection Biology, Section for Food Safety, Norwegian School of Veterinary Science, P. O. Box 8146 Dep, Oslo, N-0033, Norway
| | - Janet M Blatny
- Forsvarets Forskningsinstitutt FFI, Norwegian Defence Research Establishment, P. O. Box 25, Kjeller, N-2027, Norway
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Brul S, Bassett J, Cook P, Kathariou S, McClure P, Jasti P, Betts R. ‘Omics’ technologies in quantitative microbial risk assessment. Trends Food Sci Technol 2012. [DOI: 10.1016/j.tifs.2012.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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14
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Brown JL, Tran-Dinh N, Chapman B. Clostridium sporogenes PA 3679 and its uses in the derivation of thermal processing schedules for low-acid shelf-stable foods and as a research model for proteolytic Clostridium botulinum. J Food Prot 2012; 75:779-92. [PMID: 22488072 DOI: 10.4315/0362-028x.jfp-11-391] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The putrefactive anaerobe Clostridium sporogenes PA 3679 has been widely used as a nontoxigenic surrogate for proteolytic Clostridium botulinum in the validation of thermal processes for low-acid shelf-stable foods, as a target organism in the derivation of thermal processes that reduce the risk of spoilage of such foods to an acceptable level, and as a research model for proteolytic strains of C. botulinum. Despite the importance of this organism, our knowledge of it has remained fragmented. In this article we draw together the literature associated with PA 3679 and discuss the identity of this organism, the phylogenetic relationships that exist between PA 3679 and various strains of C. sporogenes and proteolytic C. botulinum, the heat resistance characteristics of PA 3679, the advantages and limitations associated with its use in the derivation of thermal processing schedules, and the knowledge gaps and opportunities that exist with regard to its use as a research model for proteolytic C. botulinum. Phylogenetic analysis reviewed here suggests that PA 3679 is more closely related to various strains of proteolytic C. botulinum than to selected strains, including the type strain, of C. sporogenes. Even though PA 3679 is demonstrably nontoxigenic, the genetic basis of this nontoxigenic status remains to be elucidated, and the genetic sequence of this microorganism appears to be the key knowledge gap remaining to be filled. Our comprehensive review of comparative heat resistance data gathered for PA 3679 and proteolytic strains of C. botulinum over the past 100 years supports the practice of using PA 3679 as a (typically fail-safe) thermal processing surrogate for proteolytic C. botulinum.
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Affiliation(s)
- Janelle L Brown
- CSIRO Food and Nutritional Sciences, P.O. Box 52, North Ryde, New South Wales 1670, Australia.
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