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Galié S, García-Gutiérrez C, Miguélez EM, Villar CJ, Lombó F. Biofilms in the Food Industry: Health Aspects and Control Methods. Front Microbiol 2018; 9:898. [PMID: 29867809 PMCID: PMC5949339 DOI: 10.3389/fmicb.2018.00898] [Citation(s) in RCA: 411] [Impact Index Per Article: 68.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 04/18/2018] [Indexed: 12/18/2022] Open
Abstract
Diverse microorganisms are able to grow on food matrixes and along food industry infrastructures. This growth may give rise to biofilms. This review summarizes, on the one hand, the current knowledge regarding the main bacterial species responsible for initial colonization, maturation and dispersal of food industry biofilms, as well as their associated health issues in dairy products, ready-to-eat foods and other food matrixes. These human pathogens include Bacillus cereus (which secretes toxins that can cause diarrhea and vomiting symptoms), Escherichia coli (which may include enterotoxigenic and even enterohemorrhagic strains), Listeria monocytogenes (a ubiquitous species in soil and water that can lead to abortion in pregnant women and other serious complications in children and the elderly), Salmonella enterica (which, when contaminating a food pipeline biofilm, may induce massive outbreaks and even death in children and elderly), and Staphylococcus aureus (known for its numerous enteric toxins). On the other hand, this review describes the currently available biofilm prevention and disruption methods in food factories, including steel surface modifications (such as nanoparticles with different metal oxides, nanocomposites, antimicrobial polymers, hydrogels or liposomes), cell-signaling inhibition strategies (such as lactic and citric acids), chemical treatments (such as ozone, quaternary ammonium compounds, NaOCl and other sanitizers), enzymatic disruption strategies (such as cellulases, proteases, glycosidases and DNAses), non-thermal plasma treatments, the use of bacteriophages (such as P100), bacteriocins (such us nisin), biosurfactants (such as lichenysin or surfactin) and plant essential oils (such as citral- or carvacrol-containing oils).
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Affiliation(s)
- Serena Galié
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Coral García-Gutiérrez
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Elisa M. Miguélez
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Claudio J. Villar
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Felipe Lombó
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
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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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Genotypes and the persistence survival phenotypes of Bacillus cereus isolated from UHT milk processing lines. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.06.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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54
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Moradi M, Tajik H. Biofilm removal potential of neutral electrolysed water on pathogen and spoilage bacteria in dairy model systems. J Appl Microbiol 2017; 123:1429-1437. [PMID: 28994493 DOI: 10.1111/jam.13608] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 09/28/2017] [Accepted: 10/04/2017] [Indexed: 01/13/2023]
Affiliation(s)
- M. Moradi
- Department of Food Hygiene and Quality Control Faculty of Veterinary Medicine Urmia University Urmia West Azarbaijan Iran
| | - H. Tajik
- Department of Food Hygiene and Quality Control Faculty of Veterinary Medicine Urmia University Urmia West Azarbaijan Iran
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55
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Sporeforming bacteria in beer: Occurrence, diversity, presence of hop resistance genes and fate in alcohol-free and lager beers. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ben-Ishay N, Oknin H, Steinberg D, Berkovich Z, Reifen R, Shemesh M. Enrichment of milk with magnesium provides healthier and safer dairy products. NPJ Biofilms Microbiomes 2017; 3:24. [PMID: 29038735 PMCID: PMC5636824 DOI: 10.1038/s41522-017-0032-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/12/2017] [Accepted: 09/18/2017] [Indexed: 12/13/2022] Open
Abstract
Biofilms on the surfaces of milk-processing equipment are often a major source of contamination of dairy products. Members of the genus Bacillus appear to be among the most commonly found bacteria in dairy farms and processing plants. Bacillus species may thrive in dairy farm equipment and in dairy products since they can form robust biofilms during growth within milk. We found that fortification of milk with magnesium mitigated biofilm formation by Bacillus species, and thus could notably reduce dairy product spoilage. We also show that the mode of action of Mg2+ ions is specific to inhibition of transcription of genes involved in biofilm formation. Our further findings indicate that in the presence of Mg2+ bacterial cells are hypersensitive to the heat pasteurization applied during milk processing. Additionally, we demonstrated that enrichment of milk with magnesium improved technological properties of milk products such as soft cheeses. Finally, we report that there is a notable increase in the intestinal bioavailability potential of magnesium from supplemented milk compared with that from non-supplemented milk.
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Affiliation(s)
- Noa Ben-Ishay
- Department of Food Quality and Safety, Institute of Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO) the Volcani Center, 7528809 Rishon LeZion, Israel.,The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, 76100 Rehovot, Israel
| | - Hilla Oknin
- Department of Food Quality and Safety, Institute of Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO) the Volcani Center, 7528809 Rishon LeZion, Israel.,Biofilm Research Laboratory, Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University-Hadassah, Jerusalem, Israel
| | - Doron Steinberg
- Biofilm Research Laboratory, Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University-Hadassah, Jerusalem, Israel
| | - Zipi Berkovich
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, 76100 Rehovot, Israel
| | - Ram Reifen
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, 76100 Rehovot, Israel
| | - Moshe Shemesh
- Department of Food Quality and Safety, Institute of Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO) the Volcani Center, 7528809 Rishon LeZion, Israel
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Abstract
The aim of the research was to study the features of formation of dairy equipment microflora, the ability of microorganisms to form biofilms on the noncorrosive steel surface with the different roughness and to determine the effectiveness of disinfectants. It was established, that bacteria of Bacillus, Lactobacillus genera of Enterobacteriaceae family are most often extracted from the dairy equipment after the sanitary processing by modern disinfectors, in less number of cases – staphylococci, enterococci, streptococci and pseudomonades. Extracted bacteria form mainly biofilms of the high and middle density. In 100 % of cases biofilms of the high density were formed by Bacillus spp. and Enterococcus faecalis bacteria. It indicates the fact that at the disinfection of the dairy equipment, only stable bacteria that have the ability to produce a biofilm of the high density, remain on its surface.
It was established, that the dairy equipment surface relief, namely roughness, has an influence on the process of biofilm formation in Escherichia coli. On the noncorrosive steel surface with the roughness 0,16±0,065 mcm Escherichia coli form biofilms of the lower density comparing with the surface with the density 0,63–0,072 mcm during 24 hours at the temperature 17 °С.
It was established, that working solutions of disinfectants P3-ansep CIP, Eco chlor, Medicarine and Maxidez were more effective as to plankton bacteria. Microorganisms, formed in biofilms, turned out stable to these disinfectants. Most effective disinfectant for the influence on bacteria on biofilms is Р3-oxonia active – 150. So, the obtained data indicate that for the effective sanitary processing of the dairy equipment it is necessary to use disinfectants that influence bacteria in biofilms.
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Xu S, Yang N, Zheng S, Yan F, Jiang C, Yu Y, Guo J, Chai Y, Chen Y. The spo0A-sinI-sinR Regulatory Circuit Plays an Essential Role in Biofilm Formation, Nematicidal Activities, and Plant Protection in Bacillus cereus AR156. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:603-619. [PMID: 28430084 DOI: 10.1094/mpmi-02-17-0042-r] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The rhizosphere bacterium Bacillus cereus AR156 is capable of forming biofilms, killing nematodes, and protecting plants. However, the underlying molecular mechanisms of these processes are not well understood. In this study, we found that the isogenic mutants ΔBcspo0A and ΔBcsinI have significantly reduced colonization and nematicidal activity in vitro and biological control efficacy on the tomato plant under greenhouse conditions. We further investigated the role of the spo0A-sinI-sinR regulatory circuit in biofilm formation, killing against nematodes, and biological control in AR156. Results from mutagenesis of those regulatory genes in AR156 and their heterologous expression in B. subtilis suggested that the spo0A-sinI-sinR genetic circuit is not only essential for biofilm formation and cell differentiation in AR156 but also able to functionally replace their counterparts in B. subtilis in a nearly indistinguishable fashion. Genome-wide transcriptional profiling in the wild type and the ΔBcspo0A and ΔBcsinI mutants further revealed hundreds of differentially expressed genes, likely positively regulated by both Spo0A and SinI (via SinR) in AR156. Among them, 29 genes are predicted to be directly controlled by SinR, whose counterpart in B. subtilis is a biofilm master repressor. Collectively, our studies demonstrated the essential role of the spo0A-sinI-sinR regulatory circuit in biofilm formation, cell differentiation, and bacteria-host interactions in B. cereus AR156.
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Affiliation(s)
- Sunde Xu
- 1 Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Nan Yang
- 1 Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Shiyu Zheng
- 1 Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Fang Yan
- 2 Department of Biology, Northeastern University, Boston 02115, U.S.A.; and
- 3 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Chunhao Jiang
- 3 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yiyang Yu
- 2 Department of Biology, Northeastern University, Boston 02115, U.S.A.; and
- 3 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianhua Guo
- 3 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yunrong Chai
- 2 Department of Biology, Northeastern University, Boston 02115, U.S.A.; and
| | - Yun Chen
- 1 Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
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Ribeiro MC, da Silva Fernandes M, Yoshiteru Kuaye A, Jimenez-Flores R, Gigante M. Preconditioning of the stainless steel surface affects the adhesion of Bacillus cereus spores. Int Dairy J 2017. [DOI: 10.1016/j.idairyj.2016.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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60
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Doll EV, Scherer S, Wenning M. Spoilage of Microfiltered and Pasteurized Extended Shelf Life Milk Is Mainly Induced by Psychrotolerant Spore-Forming Bacteria that often Originate from Recontamination. Front Microbiol 2017; 8:135. [PMID: 28197147 PMCID: PMC5281617 DOI: 10.3389/fmicb.2017.00135] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 01/19/2017] [Indexed: 01/28/2023] Open
Abstract
Premature spoilage and varying product quality due to microbial contamination still constitute major problems in the production of microfiltered and pasteurized extended shelf life (ESL) milk. Spoilage-associated bacteria may enter the product either as part of the raw milk microbiota or as recontaminants in the dairy plant. To identify spoilage-inducing bacteria and their routes of entry, we analyzed end products for their predominant microbiota as well as the prevalence and biodiversity of psychrotolerant spores in bulk tank milk. Process analyses were performed to determine the removal of psychrotolerant spores at each production step. To detect transmission and recontamination events, strain typing was conducted with isolates obtained from all process stages. Microbial counts in 287 ESL milk packages at the end of shelf life were highly diverse ranging from <1 to 7.9 log cfu/mL. In total, 15% of samples were spoiled. High G+C Gram-positive bacteria were the most abundant taxonomic group, but were responsible for only 31% of spoilage. In contrast, psychrotolerant spores were isolated from 55% of spoiled packages. In 90% of samples with pure cultures of Bacillus cereus sensu lato and Paenibacillus spp., counts exceeded 6 log cfu/mL. In bulk tank milk, the concentration of psychrotolerant spores was low, accounting for merely 0.5 ± 0.8 MPN/mL. Paenibacillus amylolyticus/xylanexedens was by far the most dominant species in bulk tank milk (48% of all isolates), but was never detected in ESL milk, pointing to efficient removal during manufacturing. Six large-scale process analyses confirmed a high removal rate for psychrotolerant spores (reduction by nearly 4 log-units). B. cereus sensu lato, on the contrary, was frequently found in spoiled end products, but was rarely detected in bulk tank milk. Due to low counts in bulk tank samples and efficient spore removal during production, we suggest that shelf life is influenced only to a minor extent by raw-milk-associated factors. In contrast, recontamination with spores, particularly from the B. cereus complex, seems to occur. To enhance milk quality throughout the entire shelf life, improved plant sanitation and disinfection that target the elimination of spores are necessary.
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Affiliation(s)
| | | | - Mareike Wenning
- Chair of Microbial Ecology, Institute for Food and Health, Technische Universität MünchenFreising, Germany
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62
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Ostrov I, Harel A, Bernstein S, Steinberg D, Shemesh M. Development of a Method to Determine the Effectiveness of Cleaning Agents in Removal of Biofilm Derived Spores in Milking System. Front Microbiol 2016; 7:1498. [PMID: 27713737 PMCID: PMC5031791 DOI: 10.3389/fmicb.2016.01498] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 09/07/2016] [Indexed: 11/14/2022] Open
Abstract
Microbial damages caused by biofilm forming bacteria in the dairy industry are a fundamental threat to safety and quality of dairy products. In order to ensure the optimal level of equipment hygiene in the dairy industry, it is necessary to determine the biofilm removal efficiency of cleaning agents used for cleaning-in-place (CIP) procedures. However, currently there is no standard method available for evaluating and comparing cleaning agents for use in CIP procedures in the dairy industry under realistic conditions. The present study aims to establish a CIP model system to evaluate the effectiveness of cleaning agents in removal of biofilm derived spores from the surfaces of stainless steel which is the predominant substrate in milking equipment on dairy farms. The system is based on Bacillus subtilis spores surrounded with exopolymeric substances produced by bacteria during biofilm formation. The spores applied on sampling plates were mounted on T-junctions protruding 1.5-11-times the milk pipe diameter from the main loop to resemble different levels of cleaning difficulty. The cleaning tests were conducted using commercial alkaline detergents and caustic soda at conditions which are relevant to actual farm environment. The spores removal effect was evaluated by comparing the number of viable spores (attached to sampling plates) before and after cleaning. Evaluation of the cleaning and disinfecting effect of cleaning agents toward biofilm derived spores was further performed, which indicates whether spores elimination effect of an agent is due to killing the spores or removing them from the surfaces of dairy equipment. Moreover, it was established that the presence of extracellular matrix is an important factor responsible for high level of cleaning difficulty characteristic for surface attached spores. In overall, the results of this study suggest that the developed model system simulates actual farm conditions for quantitative evaluation of the effectiveness of cleaning and disinfecting agents and their cleaning and disinfecting effect on removal of biofilm derived spores.
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Affiliation(s)
- Ievgeniia Ostrov
- Department of Food Quality and Safety, Institute for Postharvest Technology and Food Sciences, Agricultural Research OrganizationRishon LeZion, Israel
- Biofilm Research Laboratory, The Hebrew University-HadassahJerusalem, Israel
| | | | - Solange Bernstein
- Department of Food Quality and Safety, Institute for Postharvest Technology and Food Sciences, Agricultural Research OrganizationRishon LeZion, Israel
| | - Doron Steinberg
- Biofilm Research Laboratory, The Hebrew University-HadassahJerusalem, Israel
| | - Moshe Shemesh
- Department of Food Quality and Safety, Institute for Postharvest Technology and Food Sciences, Agricultural Research OrganizationRishon LeZion, Israel
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63
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Martinez RCR, Alvarenga VO, Thomazini M, Fávaro-Trindade CS, Sant'Ana ADS. Assessment of the inhibitory effect of free and encapsulated commercial nisin (Nisaplin ® ), tested alone and in combination, on Listeria monocytogenes and Bacillus cereus in refrigerated milk. Lebensm Wiss Technol 2016. [DOI: 10.1016/j.lwt.2015.12.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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64
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Rossi EM, Beilke L, Kochhann M, Sarzi DH, Tondo EC. Biosurfactant Produced by Salmonella Enteritidis SE86 Can Increase Adherence and Resistance to Sanitizers on Lettuce Leaves (Lactuca sativa L., cichoraceae). Front Microbiol 2016; 7:9. [PMID: 26834727 PMCID: PMC4722381 DOI: 10.3389/fmicb.2016.00009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/07/2016] [Indexed: 11/13/2022] Open
Abstract
Salmonella Enteritidis SE86 is an important foodborne pathogen in Southern Brazil and it is able to produce a biosurfactant. However, the importance of this compound for the microorganism is still unknown. This study aimed to investigate the influence of the biosurfactant produced by S. Enteritidis SE86 on adherence to slices of lettuce leaves and on resistance to sanitizers. First, lettuce leaves were inoculated with S. Enteritidis SE86 in order to determine the amount of biosurfactant produced. Subsequently, lettuce leaves were inoculated with S. Enteritidis SE86 with and without the biosurfactant, and the adherence and bacterial resistance to different sanitization methods were evaluated. S. Enteritidis SE86 produced biosurfactant after 16 h (emulsification index of 11 to 52.15 percent, P < 0.05) and showed greater adherence capability and resistance to sanitization methods when the compound was present. The scanning electron microscopy demonstrated that S. Enteritidis was able to adhere, form lumps, and invade the lettuce leaves' stomata in the presence of the biosurfactant. Results indicated that the biosurfactant produced by S. Enteritidis SE86 contributed to adherence and increased resistance to sanitizers when the microorganism was present on lettuce leaves.
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Affiliation(s)
- Eliandra M Rossi
- Laboratório de Microbiologia, Departamento de Ciências Biológicas e da Saúde, Universidade do Oeste de Santa CatarinaSão Miguel do Oeste, Brazil; Laboratório de Microbiologia e Controle de Alimentos, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Luniele Beilke
- Laboratório de Microbiologia, Departamento de Ciências Biológicas e da Saúde, Universidade do Oeste de Santa Catarina São Miguel do Oeste, Brazil
| | - Marília Kochhann
- Laboratório de Microbiologia, Departamento de Ciências Biológicas e da Saúde, Universidade do Oeste de Santa Catarina São Miguel do Oeste, Brazil
| | - Diana H Sarzi
- Laboratório de Microbiologia, Departamento de Ciências Biológicas e da Saúde, Universidade do Oeste de Santa Catarina São Miguel do Oeste, Brazil
| | - Eduardo C Tondo
- Laboratório de Microbiologia e Controle de Alimentos, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil
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Gopal N, Hill C, Ross PR, Beresford TP, Fenelon MA, Cotter PD. The Prevalence and Control of Bacillus and Related Spore-Forming Bacteria in the Dairy Industry. Front Microbiol 2015; 6:1418. [PMID: 26733963 PMCID: PMC4685140 DOI: 10.3389/fmicb.2015.01418] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/30/2015] [Indexed: 01/14/2023] Open
Abstract
Milk produced in udder cells is sterile but due to its high nutrient content, it can be a good growth substrate for contaminating bacteria. The quality of milk is monitored via somatic cell counts and total bacterial counts, with prescribed regulatory limits to ensure quality and safety. Bacterial contaminants can cause disease, or spoilage of milk and its secondary products. Aerobic spore-forming bacteria, such as those from the genera Sporosarcina, Paenisporosarcina, Brevibacillus, Paenibacillus, Geobacillus and Bacillus, are a particular concern in this regard as they are able to survive industrial pasteurization and form biofilms within pipes and stainless steel equipment. These single or multiple-species biofilms become a reservoir of spoilage microorganisms and a cycle of contamination can be initiated. Indeed, previous studies have highlighted that these microorganisms are highly prevalent in dead ends, corners, cracks, crevices, gaskets, valves and the joints of stainless steel equipment used in the dairy manufacturing plants. Hence, adequate monitoring and control measures are essential to prevent spoilage and ensure consumer safety. Common controlling approaches include specific cleaning-in-place processes, chemical and biological biocides and other novel methods. In this review, we highlight the problems caused by these microorganisms, and discuss issues relating to their prevalence, monitoring thereof and control with respect to the dairy industry.
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Affiliation(s)
- Nidhi Gopal
- Teagasc Food Research CentreCork, Ireland
- School of Microbiology, University College CorkCork, Ireland
| | - Colin Hill
- School of Microbiology, University College CorkCork, Ireland
- APC Microbiome InstituteCork, Ireland
| | - Paul R. Ross
- College of Science, Engineering and Food Science, University College CorkCork, Ireland
| | | | | | - Paul D. Cotter
- Teagasc Food Research CentreCork, Ireland
- APC Microbiome InstituteCork, Ireland
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66
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Checinska A, Paszczynski A, Burbank M. Bacillusand Other Spore-Forming Genera: Variations in Responses and Mechanisms for Survival. Annu Rev Food Sci Technol 2015; 6:351-69. [DOI: 10.1146/annurev-food-030713-092332] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Aleksandra Checinska
- School of Food Science, University of Idaho, Moscow, Idaho 83844-1052 and Washington State University, Pullman, Washington 99164-6376; ,
- Present address: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109;
| | - Andrzej Paszczynski
- School of Food Science, University of Idaho, Moscow, Idaho 83844-1052 and Washington State University, Pullman, Washington 99164-6376; ,
| | - Malcolm Burbank
- School of Food Science, University of Idaho, Moscow, Idaho 83844-1052 and Washington State University, Pullman, Washington 99164-6376; ,
- Present address: BioCement Technologies Inc., Seattle, Washington 98101
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67
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Caro-Astorga J, Pérez-García A, de Vicente A, Romero D. A genomic region involved in the formation of adhesin fibers in Bacillus cereus biofilms. Front Microbiol 2015; 5:745. [PMID: 25628606 PMCID: PMC4292775 DOI: 10.3389/fmicb.2014.00745] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 12/09/2014] [Indexed: 01/09/2023] Open
Abstract
Bacillus cereus is a bacterial pathogen that is responsible for many recurrent disease outbreaks due to food contamination. Spores and biofilms are considered the most important reservoirs of B. cereus in contaminated fresh vegetables and fruits. Biofilms are bacterial communities that are difficult to eradicate from biotic and abiotic surfaces because of their stable and extremely strong extracellular matrix. These extracellular matrixes contain exopolysaccharides, proteins, extracellular DNA, and other minor components. Although B. cereus can form biofilms, the bacterial features governing assembly of the protective extracellular matrix are not known. Using the well-studied bacterium B. subtilis as a model, we identified two genomic loci in B. cereus, which encodes two orthologs of the amyloid-like protein TasA of B. subtilis and a SipW signal peptidase. Deletion of this genomic region in B. cereus inhibited biofilm assembly; notably, mutation of the putative signal peptidase SipW caused the same phenotype. However, mutations in tasA or calY did not completely prevent biofilm formation; strains that were mutated for either of these genes formed phenotypically different surface attached biofilms. Electron microscopy studies revealed that TasA polymerizes to form long and abundant fibers on cell surfaces, whereas CalY does not aggregate similarly. Heterologous expression of this amyloid-like cassette in a B. subtilis strain lacking the factors required for the assembly of TasA amyloid-like fibers revealed (i) the involvement of this B. cereus genomic region in formation of the air-liquid interphase pellicles and (ii) the intrinsic ability of TasA to form fibers similar to the amyloid-like fibers produced by its B. subtilis ortholog.
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Affiliation(s)
- Joaquín Caro-Astorga
- Departamento de Microbiología, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga Málaga, Spain
| | - Alejandro Pérez-García
- Departamento de Microbiología, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga Málaga, Spain
| | - Antonio de Vicente
- Departamento de Microbiología, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga Málaga, Spain
| | - Diego Romero
- Departamento de Microbiología, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga Málaga, Spain
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68
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Flores-Urbán KA, Natividad-Bonifacio I, Vázquez-Quiñones CR, Vázquez-Salinas C, Quiñones-Ramírez EI. Detection of toxigenic Bacillus cereus strains isolated from vegetables in Mexico City. J Food Prot 2014; 77:2144-7. [PMID: 25474064 DOI: 10.4315/0362-028x.jfp-13-479] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Bacillus cereus can cause diarrhea and emetic syndromes after ingestion of food contaminated with it. This ability is due to the production of enterotoxins by this microorganism, these being the hemolysin BL complex, which is involved in the diarrheal syndrome, and cereulide, which is responsible for the emetic syndrome. The detection of genes associated with the production of these toxins can predict the virulence of strains isolated from contaminated food. In this paper, we analyzed 100 samples of vegetables, 25 of each kind (broccoli, coriander, carrot, and lettuce) obtained from different markets in Mexico City and its metropolitan area. B. cereus was isolated in 32, 44, 84, and 68% of the samples of broccoli, carrot, lettuce, and coriander, respectively. The hblA gene (encoding one of the three subunits of hemolysin BL) was amplified in 100% of the B. cereus isolates, and the ces gene (encoding the cereulide) could not be amplified from any of them. This is the first report of B. cereus isolation from the vegetables analyzed in this work and, also, the first report in Mexico of the isolation from vegetables of strains with potential virulence. The results should serve as evidence of the potential risk of consuming these foods without proper treatment.
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Affiliation(s)
- Karen A Flores-Urbán
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Calle Carpio y Plan de Ayala s/n, C.P. 11340, Mexico City, Mexico
| | - Iván Natividad-Bonifacio
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Calle Carpio y Plan de Ayala s/n, C.P. 11340, Mexico City, Mexico
| | - Carlos R Vázquez-Quiñones
- Departamento de Biotecnología, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco 186, Colonia Vicentina, C.P. 09340, Mexico City, Mexico
| | - Carlos Vázquez-Salinas
- Departamento de Biotecnología, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco 186, Colonia Vicentina, C.P. 09340, Mexico City, Mexico
| | - Elsa Irma Quiñones-Ramírez
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Calle Carpio y Plan de Ayala s/n, C.P. 11340, Mexico City, Mexico.
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69
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Prevalence and characterization of Bacillus cereus group from various marketed dairy products in India. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s13594-014-0174-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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70
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Faille C, Bénézech T, Midelet-Bourdin G, Lequette Y, Clarisse M, Ronse G, Ronse A, Slomianny C. Sporulation of Bacillus spp. within biofilms: A potential source of contamination in food processing environments. Food Microbiol 2014; 40:64-74. [DOI: 10.1016/j.fm.2013.12.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 12/10/2013] [Accepted: 12/24/2013] [Indexed: 01/05/2023]
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71
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Sudhaus N, Nagengast H, Pina-Pérez MC, Martínez A, Klein G. Effectiveness of a peracetic acid-based disinfectant against spores of Bacillus cereus under different environmental conditions. Food Control 2014. [DOI: 10.1016/j.foodcont.2013.09.063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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72
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Pasvolsky R, Zakin V, Ostrova I, Shemesh M. Butyric acid released during milk lipolysis triggers biofilm formation of Bacillus species. Int J Food Microbiol 2014; 181:19-27. [PMID: 24801271 DOI: 10.1016/j.ijfoodmicro.2014.04.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 04/03/2014] [Accepted: 04/07/2014] [Indexed: 10/25/2022]
Abstract
Bacillus species form biofilms within milking pipelines and on surfaces of equipment in the dairy industry which represent a continuous hygiene problem and can lead to serious economic losses due to food spoilage and equipment impairment. Although much is known about the mechanism by which the model organism Bacillus subtilis forms biofilms in laboratory mediums in vitro, little is known of how these biofilms are formed in natural environments such as milk. Besides, little is known of the signaling pathways leading to biofilm formation in other Bacillus species, such as Bacillus cereus and Bacillus licheniformis, both of which are known to contaminate milk. In this study, we report that milk triggers the formation of biofilm-related structures, termed bundles. We show this to be a conserved phenomenon among all Bacillus members tested. Moreover, we demonstrate that the tasA gene, which encodes a major portion of the matrix which holds the biofilm together, is vital for this process. Furthermore, we show that the free fatty acid (FFA) - butyric acid (BA), which is released during lipolysis of milk fat and demonstrates antimicrobial activity, is the potent trigger for biofilm bundle formation. We finally show that BA-triggered biofilm bundle formation is mediated by the histidine kinase, KinD. Taken together, these observations indicate that BA, which is a major FFA within milk triggers biofilm formation in a conserved mechanism among members of the Bacillus genus.
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Affiliation(s)
- Ronit Pasvolsky
- Department of Food Quality and Safety, Agricultural Research Organization (ARO), Bet-Dagan, Israel
| | - Varda Zakin
- Department of Food Quality and Safety, Agricultural Research Organization (ARO), Bet-Dagan, Israel
| | - Ievgeniia Ostrova
- Department of Food Quality and Safety, Agricultural Research Organization (ARO), Bet-Dagan, Israel
| | - Moshe Shemesh
- Department of Food Quality and Safety, Agricultural Research Organization (ARO), Bet-Dagan, Israel.
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73
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Stoeckel M, Abduh SBM, Atamer Z, Hinrichs J. Inactivation ofBacillusspores in batch vs continuous heating systems at sterilisation temperatures. INT J DAIRY TECHNOL 2014. [DOI: 10.1111/1471-0307.12134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marina Stoeckel
- Department Dairy Science and Technology; Institute of Food Science and Biotechnology; Universität Hohenheim; Garbenstr. 21 70599 Stuttgart Germany
| | - Setya B M Abduh
- Department Dairy Science and Technology; Institute of Food Science and Biotechnology; Universität Hohenheim; Garbenstr. 21 70599 Stuttgart Germany
| | - Zeynep Atamer
- Department Dairy Science and Technology; Institute of Food Science and Biotechnology; Universität Hohenheim; Garbenstr. 21 70599 Stuttgart Germany
| | - Jörg Hinrichs
- Department Dairy Science and Technology; Institute of Food Science and Biotechnology; Universität Hohenheim; Garbenstr. 21 70599 Stuttgart Germany
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74
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Reis ALS, Montanhini MTM, Bittencourt JVM, Destro MT, Bersot LS. Gene detection and toxin production evaluation of hemolysin BL of Bacillus cereus isolated from milk and dairy products marketed in Brazil. Braz J Microbiol 2014; 44:1195-8. [PMID: 24688511 PMCID: PMC3958187 DOI: 10.1590/s1517-83822013000400024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 04/04/2013] [Indexed: 11/22/2022] Open
Abstract
Bacillus cereusis an ubiquitous, spore-forming bacteria that can survive pasteurization and the majority of the heating processes used in the dairy industry. Besides, it is a pathogen responsible for different types of food poisoning. One type of foodborne disease caused by B.cereusis the diarrheal syndrome, which is caused by the ingestion of vegetative cells producing toxins in the small intestine. One virulence factor for the diarrheal syndrome is the toxin hemolysin BL (HBL), a three-component protein formed by the L1, L2 and B components. In order to evaluate the presence of diarrheal strains isolated from milk and dairy products, 63 B. cereus isolates were obtained from 260 samples of UHT milk, pasteurized milk and powdered milk, sold in commercial establishments and from different brands. The isolates were subjected to the Polymerase Chain Reaction (PCR) for the detection of the encoding genes for the L1, L2 and B components and the toxin production capacity were evaluated with an immunoassay. A total of 23 [36.5%] isolates were identified carrying simultaneously the three tested genes, from which, 20 [86.9%] showed toxigenic capacity. 26 [41.3%] isolates did not carry any of genes tested and the other 14 [22.2%] were positive for one or two of them. The results showed a high toxigenic capacity among the B. cereus isolates able to produce the HBL, indicating a potential risk for consumers.
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Affiliation(s)
- Andre L S Reis
- Programa de Pós-Graduação em Engenharia de Alimentos, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Maike T M Montanhini
- Programa de Pós-Graduação em Engenharia de Alimentos, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Juliana V M Bittencourt
- Laboratório de Bioengenharia, Universidade Tecnológica Federal do Paraná, Ponta Grossa, PR, Brazil
| | - Maria T Destro
- Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Luciano S Bersot
- Programa de Pós-Graduação em Engenharia de Alimentos, Universidade Federal do Paraná, Curitiba, PR, Brazil
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75
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Khanal SN, Anand S, Muthukumarappan K, Huegli M. Inactivation of thermoduric aerobic sporeformers in milk by ultrasonication. Food Control 2014. [DOI: 10.1016/j.foodcont.2013.09.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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76
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Kumari S, Sarkar PK. In vitro model study for biofilm formation by Bacillus cereus in dairy chilling tanks and optimization of clean-in-place (CIP) regimes using response surface methodology. Food Control 2014. [DOI: 10.1016/j.foodcont.2013.08.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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77
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Modelling Bacillus cereus adhesion on stainless steel surface as affected by temperature, pH and time. Int Dairy J 2014. [DOI: 10.1016/j.idairyj.2013.08.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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78
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Faille C, Ronse A, Dewailly E, Slomianny C, Maes E, Krzewinski F, Guerardel Y. Presence and function of a thick mucous layer rich in polysaccharides around Bacillus subtilis spores. BIOFOULING 2014; 30:845-858. [PMID: 25115519 DOI: 10.1080/08927014.2014.939073] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study was designed to establish the presence and function of the mucous layer surrounding spores of Bacillus subtilis. First, an external layer of variable thickness and regularity was often observed on B. subtilis spores. Further analyses were performed on B. subtilis 98/7 spores surrounded by a thick layer. The mechanical removal of the layer did not affect their resistance to heat or their ability to germinate but rendered the spore less hydrophilic, more adherent to stainless steel, and more resistant to cleaning. This layer was mainly composed of 6-deoxyhexoses, ie rhamnose, 3-O-methyl-rhamnose and quinovose, but also of glucosamine and muramic lactam, known also to be a part of the bacterial peptidoglycan. The specific hydrolysis of the peptidoglycan using lysozyme altered the structure of the required mucous layer and affected the physico-chemical properties of the spores. Such an outermost mucous layer has also been seen on spores of B. licheniformis and B. clausii isolated from food environments.
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Affiliation(s)
- Christine Faille
- a INRA, UR638 Interface Processes and Hygiene of Materials , F-59651 Villeneuve d'Ascq , France
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79
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Anand S, Singh D. Resistance of the constitutive microflora of biofilms formed on whey reverse-osmosis membranes to individual cleaning steps of a typical clean-in-place protocol. J Dairy Sci 2013; 96:6213-22. [PMID: 23958024 DOI: 10.3168/jds.2013-7012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 06/09/2013] [Indexed: 11/19/2022]
Abstract
This experiment evaluates the effectiveness of individual steps of a clean-in-place protocol against the biofilm constitutive microflora isolated from the biofilms developed on whey reverse-osmosis membranes, aged 2 to 14 mo, under industrial processing conditions. The isolates used for the in vitro resistance studies included species of Bacillus, Enterococcus, Streptococcus, Staphylococcus, Micrococcus, Aeromonas, Corynebacterium, Pseudomonas, Klebsiella, and Escherichia. The 6 cleaning steps (alkali, surfactant, acid, enzyme, a second surfactant, and sanitizer treatment) revealed resistance of isolates in both planktonic and biofilm-embedded cell states. The most effective step was the acid treatment, which resulted in 4.54 to 7.90 and 2.09 to 5.02 log reductions of the planktonic and biofilm-embedded cells, respectively. Although the sanitizer step causing a reduction of 4.91 to 8.33 log in the case of planktonic cells, it was less effective against the biofilm-embedded cells, resulting in a reduction of 0.59 to 1.64 log. Bacillus spp. showed the highest resistance in both planktonic, as well as embedded cell states.
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Affiliation(s)
- Sanjeev Anand
- Midwest Dairy Foods Research Center, Dairy Science Department, South Dakota State University, Brookings 57006.
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80
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Identification and genetic diversity of Bacillus cereus strains isolated from a pasteurized milk processing line in Algeria. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s13594-012-0093-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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81
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Tetreau G, Bayyareddy K, Jones CM, Stalinski R, Riaz MA, Paris M, David JP, Adang MJ, Després L. Larval midgut modifications associated with Bti resistance in the yellow fever mosquito using proteomic and transcriptomic approaches. BMC Genomics 2012; 13:248. [PMID: 22703117 PMCID: PMC3460780 DOI: 10.1186/1471-2164-13-248] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 05/25/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacillus thuringiensis var. israelensis (Bti) is a natural larval mosquito pathogen producing pore-forming toxins targeting the midgut of Diptera larvae. It is used worldwide for mosquito control. Resistance mechanisms of an Aedes aegypti laboratory strain selected for 30 generations with field-collected leaf litter containing Bti toxins were investigated in larval midguts at two levels: 1. gene transcription using DNA microarray and RT-qPCR and 2. differential expression of brush border membrane proteins using DIGE (Differential In Gel Electrophoresis). RESULTS Several Bti Cry toxin receptors including alkaline phosphatases and N-aminopeptidases and toxin-binding V-ATPases exhibited altered expression levels in the resistant strain. The under-expression of putative Bti-receptors is consistent with Bt-resistance mechanisms previously described in Lepidoptera. Four soluble metalloproteinases were found under-transcribed together with a drastic decrease of metalloproteinases activity in the resistant strain, suggesting a role in resistance by decreasing the amount of activated Cry toxins in the larval midgut. CONCLUSIONS By combining transcriptomic and proteomic approaches, we detected expression changes at nearly each step of the ingestion-to-infection process, providing a short list of genes and proteins potentially involved in Bti-resistance whose implication needs to be validated. Collectively, these results open the way to further functional analyses to better characterize Bti-resistance mechanisms in mosquitoes.
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Affiliation(s)
- Guillaume Tetreau
- Laboratoire d'Ecologie Alpine, LECA-UMR 5553, Université de Grenoble 1, BP 53, 38041 Grenoble cedex 09, France.
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82
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Decreased toxicity of Bacillus thuringiensis subsp. israelensis to mosquito larvae after contact with leaf litter. Appl Environ Microbiol 2012; 78:5189-95. [PMID: 22610426 DOI: 10.1128/aem.00903-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing Cry and Cyt proteins, which are toxic for mosquito larvae. Nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. In the present work, we investigated the behavior of B. thuringiensis subsp. israelensis toxic crystals sprayed on leaf litter. In the presence of leaf litter, a 60% decrease in the amount of Cyt toxin detectable by immunology (enzyme-linked immunosorbent assays [ELISAs]) was observed, while the respective proportions of Cry toxins were not affected. The toxicity of Cry toxins toward Aedes aegypti larvae was not affected by leaf litter, while the synergistic effect of Cyt toxins on all B. thuringiensis subsp. israelensis Cry toxins was decreased by about 20% when mixed with leaf litter. The toxicity of two commercial B. thuringiensis subsp. israelensis strains (VectoBac WG and VectoBac 12AS) and a laboratory-produced B. thuringiensis subsp. israelensis strain decreased by about 70% when mixed with leaf litter. Taken together, these results suggest that Cyt toxins interact with leaf litter, resulting in a decreased toxicity of B. thuringiensis subsp. israelensis in litter-rich environments and thereby dramatically reducing the efficiency of mosquitocidal treatments.
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83
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Pagedar A, Singh J. Influence of physiological cell stages on biofilm formation by Bacillus cereus of dairy origin. Int Dairy J 2012. [DOI: 10.1016/j.idairyj.2011.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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84
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Marchand S, De Block J, De Jonghe V, Coorevits A, Heyndrickx M, Herman L. Biofilm Formation in Milk Production and Processing Environments; Influence on Milk Quality and Safety. Compr Rev Food Sci Food Saf 2012. [DOI: 10.1111/j.1541-4337.2011.00183.x] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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85
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Identification and characterization of psychrotolerant sporeformers associated with fluid milk production and processing. Appl Environ Microbiol 2012; 78:1853-64. [PMID: 22247129 DOI: 10.1128/aem.06536-11] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Psychrotolerant spore-forming bacteria represent a major challenge to the goal of extending the shelf life of pasteurized dairy products. The objective of this study was to identify prominent phylogenetic groups of dairy-associated aerobic sporeformers and to characterize representative isolates for phenotypes relevant to growth in milk. Analysis of sequence data for a 632-nucleotide fragment of rpoB showed that 1,288 dairy-associated isolates (obtained from raw and pasteurized milk and from dairy farm environments) clustered into two major divisions representing (i) the genus Paenibacillus (737 isolates, including the species Paenibacillus odorifer, Paenibacillus graminis, and Paenibacillus amylolyticus sensu lato) and (ii) Bacillus (n = 467) (e.g., Bacillus licheniformis sensu lato, Bacillus pumilus, Bacillus weihenstephanensis) and genera formerly classified as Bacillus (n = 84) (e.g., Viridibacillus spp.). When isolates representing the most common rpoB allelic types (ATs) were tested for growth in skim milk broth at 6°C, 6/9 Paenibacillus isolates, but only 2/8 isolates representing Bacillus subtypes, grew >5 log CFU/ml over 21 days. In addition, 38/40 Paenibacillus isolates but only 3/47 Bacillus isolates tested were positive for β-galactosidase activity (including some isolates representing Bacillus licheniformis sensu lato, a common dairy-associated clade). Our study confirms that Paenibacillus spp. are the predominant psychrotolerant sporeformers in fluid milk and provides 16S rRNA gene and rpoB subtype data and phenotypic characteristics facilitating the identification of aerobic spore-forming spoilage organisms of concern. These data will be critical for the development of detection methods and control strategies that will reduce the introduction of psychrotolerant sporeformers and extend the shelf life of dairy products.
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86
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Ekman JV, Kruglov A, Andersson MA, Mikkola R, Raulio M, Salkinoja-Salonen M. Cereulide produced by Bacillus cereus increases the fitness of the producer organism in low-potassium environments. MICROBIOLOGY-SGM 2012; 158:1106-1116. [PMID: 22241046 DOI: 10.1099/mic.0.053520-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cereulide, produced by certain Bacillus cereus strains, is a lipophilic cyclic peptide of 1152 Da that binds K(+) ions with high specificity and affinity. It is toxic to humans, but its role for the producer organism is not known. We report here that cereulide operates for B. cereus to scavenge potassium when the environment is growth limiting for this ion. Cereulide-producing B. cereus showed higher maximal growth rates (µ(max)) than cereulide non-producing B. cereus in K(+)-deficient medium (K(+) concentration ~1 mM). The cereulide-producing strains grew faster in K(+)-deficient than in K(+)-rich medium with or without added cereulide. Cereulide non-producing B. cereus neither increased µ(max) in K(+)-deficient medium compared with K(+)-rich medium, nor benefited from added cereulide. Cereulide-producing strains outcompeted GFP-labelled Bacillus thuringiensis in potassium-deficient (K(+) concentration ~1 mM) but not in potassium-rich (K(+) concentration ~30 mM) medium. Exposure to 2 µM cereulide in potassium-free medium lacking an energy source caused, within seconds, a major efflux of cellular K(+) from B. cereus not producing cereulide as well as from Bacillus subtilis. Cereulide depleted the cereulide non-producing B. cereus and B. subtilis cells of a major part of their K(+) stores, but did not affect cereulide-producing B. cereus strains. Externally added 6-10 µM cereulide triggered the generation of biofilms and pellicles by B. cereus. The results indicate that both endogenous and externally accessible cereulide supports the fitness of cereulide-producing B. cereus in environments where the potassium concentration is low.
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Affiliation(s)
- Jaakko V Ekman
- Department of Food and Environmental Science, PO Box 56, 00014 University of Helsinki, Helsinki, Finland
| | - Alexey Kruglov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, Pushchino, Moscow Region, 142290 Russia
| | - Maria A Andersson
- Department of Food and Environmental Science, PO Box 56, 00014 University of Helsinki, Helsinki, Finland
| | - Raimo Mikkola
- Department of Food and Environmental Science, PO Box 56, 00014 University of Helsinki, Helsinki, Finland
| | - Mari Raulio
- Department of Food and Environmental Science, PO Box 56, 00014 University of Helsinki, Helsinki, Finland
| | - Mirja Salkinoja-Salonen
- Department of Food and Environmental Science, PO Box 56, 00014 University of Helsinki, Helsinki, Finland
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87
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Abstract
Bacterial biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that is attached to a surface. Biofilms protect and allow bacteria to survive and thrive in hostile environments. Bacteria within biofilms can withstand host immune responses, and are much less susceptible to antibiotics and disinfectants when compared with their planktonic counterparts. The ability to form biofilms is now considered a universal attribute of micro-organisms. Diseases associated with biofilms require novel methods for their prevention, diagnosis and treatment; this is largely due to the properties of biofilms. Surprisingly, biofilm formation by bacterial pathogens of veterinary importance has received relatively little attention. Here, we review the current knowledge of bacterial biofilms as well as studies performed on animal pathogens.
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