MODELING OF THE GERMINATION OF SPORES FROM CLOSTRIDIUM PERFRINGENS FOOD POISONING ISOLATES
Clostridium perfringens type A isolates carrying a chromosomal gene for enterotoxin production (chromosomal c. perfringens enterotoxin [C-cpe]strains) are frequent causative agents of food poisoning. Predictive models for their growth in meat products have been published; however, the development of germination models needs further research. In this study, the Weibull function was used to describe the germination of C-cpe food poisoning strains in phosphate and Tris–HCl buffer as affected by pH (5.8–8.5), germinant concentration (1–100 mM KCl) and germination temperature (23–60C). As indicated by estimators of model accuracy and bias, an empirical model for spore germination as a function of germination temperature only, predicted accurately the germination potential of 4 C-cpe food poisoning strains in buffer and in laboratory media in the 23–50C range. PRACTICAL APPLICATIONS
Thermal processing models based on the inactivation of a heat-resistant spore ignore the potential germination and outgrowth of spore survivors as recommended by new food safety guidelines. Germination models for spore survivors to be used in conjunction with outgrowth models should be developed using as samples the product of interest because the bioavailability and concentration of germinants such as ions and free amino acids vary with the product and its manufacturing process. Another germination model application is in conjunction with new processing technologies such as high pressure processing (HPP). The inactivation of bacterial spores has been a major challenge to HPP process developers. Since germinated spores are sensitive to pressure, germination models would be useful to design combined strategies of food thermal treatment and HPP.
Document Type: Research Article
Publication date: 2010-02-01