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Influence of pH and temperature on the growth of and toxin production by neurotoxigenic strains of Clostridium butyricum type E.

Author(s) : ANNIBALLI F., FENICIA L., FRANCIOSA G., et al.

Type of article: Article

Summary

Strains of Clostridium butyricum that produce botulinal toxin type E have been implicated in outbreaks of foodborne botulism in China, India, and Italy; the conditions that are favourable for the growth and toxinogenesis of these strains remain to be established. The authors determined the temperatures and pH levels most conducive to the growth of and toxin production by the six strains of neurotoxigenic C. butyricum implicated in outbreaks of infective and foodborne botulism in Italy. The strains were cultured for 180 days on Trypticase-peptone-glucose-yeast extract broth at various pHs at 30 °C and at various temperatures (10, 12, and 15 °C) at pH 7.0. Growth was determined by checking for turbidity; toxin production was determined by the mouse bioassay. Two foods were inoculated: mascarpone cheese incubated at 25 and 15 °C and pesto sauce incubated at 25 °C. The lowest pH at which growth and toxin production occurred was 4.8 and 43 and 44 days of incubation, respectively. The lowest temperature at which growth and toxin production occurred after 15 days was 12 °C, with growth and toxin production. For both foods, toxin production was observed after 5 days at 25 °C. Since the strains did not show particularly psychrotrophic behaviour, 4 °C can be considered a sufficiently low temperature for the inhibition of growth. However, the observation of toxin production in foods at room temperature and at abused refrigeration temperatures demands that these strains be considered a new risk for the food industry.

Details

  • Original title: Influence of pH and temperature on the growth of and toxin production by neurotoxigenic strains of Clostridium butyricum type E.
  • Record ID : 2003-0205
  • Languages: English
  • Source: Journal of Food Protection - vol. 65 - n. 8
  • Publication date: 2002/08
  • Document available for consultation in the library of the IIR headquarters only.

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