9-3 |
Adaptations to heat stress in Clostridium perfringens. |
J. S. NOVAK, Food Safety Research Unit, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598 The increased production of minimally-processed, extended shelf-life, refrigerated foods has resulted in the potential for food borne disease outbreaks from surviving pathogenic spore-formers such as Clostridium perfringens. Currently food processing methods cannot assure elimination of heat resistant spores from food borne pathogens without compromising the nutrient and organoleptic attributes of the foods. C. perfringens is the causative agent of illness characterized by abdominal cramps and diarrheal symptoms attributed to enterotoxin production upon sporulation of large numbers of vegetative cells in the intestine. Control methods concentrate on the inhibition of spore germination, outgrowth, and multiplication of vegetative cells from C. perfringens. Exposure of vegetative cells to sublethal temperatures may result in increased heat resistance properties of the pathogen and potential for food borne illness. Transient adaptations to heat include the increased cellular synthesis of proteins which play a role in enhancing pathogen survival. These include various heat-shock proteins, chaperonins, proteases, small acid-soluble and ribosomal proteins. Pathogen adaptations to heat may also result in increased protein and DNA stabilities required during spore assembly for increased thermal resistance and survival.
Session 9, Survival of pathogenic microorganisms in hostile environments
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