Assessment of the potential for growth and neurotoxin formation by non-proteolytic Clostridium botulinum in short shelf-life commercial foods designed to be stored chilled☆

Peck, Michael W.; Goodburn, Kaarin; Betts, Roy; Stringer, Sandra C.

doi:10.1016/j.tifs.2007.12.006

Cited by 67 publications

(44 citation statements)

References 50 publications

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“…Ready-to-eat (RTE) foods have become increasingly popular in the last two decades, particularly in metropolitan areas (Peck et al, 2008). In Tehran, Capital of Iran, there has been a marked increase in the sales of RTE food products in recent years.…”

Section: Introductionmentioning

confidence: 99%

Microbiological quality of ready-to-eat foods of Tehran province

Mashak¹,

Ali²,

Ehsani³

et al. 2015

Afr. J. Food Sci.

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Recontamination of ready-to-eat (RTE) products during post-processing may be the cause of outbreaks of food-borne disease. In this study, a total of 150 RTE samples were obtained for bacteriological examination (coliforms, Escherichia coli, Staphylococcus aureus, Salmonella, Bacillus cereus, Psychrotrophic bacteria and Psychrophilic bacteria). Various types of RTE food products that contained frozen (cooked and semi-cooked) and refrigerated (cooked) poultry meat foods, were purchased randomly periodically in January and March, 2012. 65% of cooked samples and 62% of semi cooked samples contain more than 10 2 CFU/g coliform, while S. aureus was more than 10 2 CFU/g in 35 and 40% of samples, respectively. Also 28% of cooked samples and 44% of semi cooked samples contained E. coli. 14% of all samples were contaminated by Salmonella. The results for enumeration of B. cereus, psychrophilic and psychrotrophic microorganisms were: 2/96 ± 0/09 log CFU/g, 5/02 ± 1/77 log CFU/g and 3/05±0/04 log CFU/g, respectively.

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Section: Introductionmentioning

confidence: 99%

Microbiological quality of ready-to-eat foods of Tehran province

Mashak¹,

Ali²,

Ehsani³

et al. 2015

Afr. J. Food Sci.

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“…Microarray analysis enabled identification of coding sequences whose expression profiles matched those of the neurotoxin cluster. Further research is needed to determine whether these are connected to neurotoxin formation or are merely growth phase associated.Proteolytic Clostridium botulinum and nonproteolytic C. botulinum are the two neurotoxigenic clostridia most frequently associated with food-borne botulism (22,23,24), an intoxication caused by consumption of contaminated food containing preformed botulinum neurotoxin. The botulinum neurotoxins are the most potent toxins known, with as little as 30 ng being potentially fatal (24, 25).…”

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confidence: 99%

“…The botulinum neurotoxins are the most potent toxins known, with as little as 30 ng being potentially fatal (24, 25). There are seven botulinum neurotoxin subtypes (A to G) and also a number of subtypes, of which subtype A1 has received the most attention to date (25 Carbon dioxide is frequently used as an antimicrobial gas in modified atmosphere packaging (MAP) of food (14,22,23). However, strains of nonproteolytic C. botulinum types B and E, despite having increased lag time and reduced growth rate (13, 15), display an increase in both neurotoxin gene expression and neurotoxin formation with higher CO 2 concentrations (5, 20).…”

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confidence: 99%

“…Carbon dioxide is frequently used as an antimicrobial gas in modified atmosphere packaging (MAP) of food (14,22,23). However, strains of nonproteolytic C. botulinum types B and E, despite having increased lag time and reduced growth rate (13,15), display an increase in both neurotoxin gene expression and neurotoxin formation with higher CO 2 concentrations (5,20).…”

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confidence: 99%

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Effects of Carbon Dioxide on Growth of ProteolyticClostridium botulinum, Its Ability To Produce Neurotoxin, and Its Transcriptome

Artin

Mason

et al. 2010

Appl Environ Microbiol

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The antimicrobial gas carbon dioxide is frequently used in modified atmosphere packaging. In the present study, the effects of CO 2 (10 to 70%, vol/vol) on gene expression (measured using quantitative reverse transcription-PCR and a whole-genome DNA microarray) and neurotoxin formation (measured using an enzyme-linked immunosorbent assay [ELISA]) by proteolytic Clostridium botulinum type A1 strain ATCC 3502 were studied during the growth cycle. Interestingly, in marked contrast to the situation with nonproteolytic C. botulinum types B and E, CO 2 had little effect on any of these parameters. At all CO 2 concentrations, relative expression of neurotoxin cluster genes peaked in the transition between exponential and stationary phases, with evidence of a second rise in expression in late stationary phase. Microarray analysis enabled identification of coding sequences whose expression profiles matched those of the neurotoxin cluster. Further research is needed to determine whether these are connected to neurotoxin formation or are merely growth phase associated.Proteolytic Clostridium botulinum and nonproteolytic C. botulinum are the two neurotoxigenic clostridia most frequently associated with food-borne botulism (22,23,24), an intoxication caused by consumption of contaminated food containing preformed botulinum neurotoxin. The botulinum neurotoxins are the most potent toxins known, with as little as 30 ng being potentially fatal (24, 25). There are seven botulinum neurotoxin subtypes (A to G) and also a number of subtypes, of which subtype A1 has received the most attention to date (25 Carbon dioxide is frequently used as an antimicrobial gas in modified atmosphere packaging (MAP) of food (14,22,23). However, strains of nonproteolytic C. botulinum types B and E, despite having increased lag time and reduced growth rate (13, 15), display an increase in both neurotoxin gene expression and neurotoxin formation with higher CO 2 concentrations (5, 20). The purpose of the present study was to quantify the effect of CO 2 concentration on the growth, relative gene expression, and neurotoxin production by proteolytic C. botulinum type A1 strain ATCC 3502. Relative expression of cntA/A1 and cntR was measured using a new quantitative reverse transcription-PCR (qRT-PCR) method, and a DNA microarray was used to study the transcriptome. MATERIALS AND METHODSCulture conditions and growth parameters. Overnight cultures of proteolytic C. botulinum type A1 strain ATCC 3502 were grown in TPY medium flushed with the appropriate gas mixture (10%, 35%, or 70% CO 2 ; 10% H 2 ; and the balance N 2 [by vol]) and used to inoculate flasks of similarly treated TPY-C broth (5). The initial pH values of the media were 6.8 to 6.4, reflecting the increasing CO 2 concentration. Cultures were grown at 37°C in an anaerobic workstation with the same atmosphere, each in triplicate. Samples for RNA and neurotoxin measurement were withdrawn at four to nine time points during the experiment. Maximum specific growth rates [(OD)] of the change in optical...

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“…Therefore, foods may be contaminated with spores from many possible sources. Due to the increased consumer demand for ready-to-eat foods containing natural ingredients and with the absence of preservatives, the safety and quality of these products rely on mild processing conditions and refrigerated storage (11,25). Such conditions, especially temperature abuse, can significantly compromise the botulinal safety of foods.…”

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Construction of a Nontoxigenic Clostridium botulinum Strain for Food Challenge Studies

Bradshaw

Marshall

Heap

et al. 2010

Appl Environ Microbiol

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Clostridium botulinum produces the most poisonous natural toxin known and is a perennial concern to the food industry and to regulatory agencies due to the potential threat of food-borne botulism. To ensure the botulinal safety of foods, rigorous food challenge testing to validate food-processing conditions and food formulations has been routinely performed. Detection of the botulinum neurotoxin is performed by using a mouse bioassay and/or in vitro assays. There has been considerable interest by the food industry and regulatory agencies in minimizing or even replacing the use of animals in these challenge studies. In addition, due to stringent select-agent regulations, the testing of various foods using toxigenic C. botulinum strains requires facilities and personnel that are certified for work with this organism. For this purpose we propose to generate sets of nontoxigenic C. botulinum strains from proteolytic and nonproteolytic groups that differ from the wild-type strains only by their inability to produce botulinum neurotoxin. In this initial study we describe the generation of a nontoxigenic mutant of C. botulinum strain 62A using the ClosTron mutagenesis system by inserting a group II intron into the botulinum neurotoxin type A gene (bont/A). The mutant clones were nontoxigenic as determined by Western blots and mouse bioassays but showed physiological characteristics, including growth properties and sporulation, that were similar to those of the parent strain in laboratory media. Additional studies will be required to evaluate comparable characteristics in various food matrices. The availability of suitable nontoxigenic C. botulinum strains for food challenge studies will be beneficial for enhancing the botulinal safety of foods as well as increasing the biosafety of workers and may eliminate the use of laboratory animals.

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Assessment of the potential for growth and neurotoxin formation by non-proteolytic Clostridium botulinum in short shelf-life commercial foods designed to be stored chilled☆

Cited by 67 publications

References 50 publications

Microbiological quality of ready-to-eat foods of Tehran province

Microbiological quality of ready-to-eat foods of Tehran province

Effects of Carbon Dioxide on Growth of ProteolyticClostridium botulinum, Its Ability To Produce Neurotoxin, and Its Transcriptome

Construction of a Nontoxigenic Clostridium botulinum Strain for Food Challenge Studies

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