MICROBIAL MODELING AND BIOINFORMATICS FOR FOOD SAFETY AND SECURITY
Location: Residue Chemistry and Predictive Microbiology
Title: Potential for growth of Clostridium perfringens from spores in pork scrapple during cooling
Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2009
Publication Date: February 1, 2010
Citation: Juneja, V.K., Porto Fett, A.C., Gartner, K., Tuft, L., Luchansky, J.B. 2010. Potential for growth of Clostridium perfringens from spores in pork scrapple during cooling. Foodborne Pathogens and Disease. 7(2)153-157.
Interpretive Summary: One of the most common types of food poisoning in the United States is caused by the bacterium, Clostridium perfringens. Illnesses have been traditionally associated with inadequate cooling practices in retail food service operations. Thus, there was a need to determine the cooling time and temperature for cooked scrapple, an ethnic food, to remain pathogen-free and provide vital data for performing risk assessment on cooked meat. We determined that cooling times for scrapple after heat processing can be extended to 14 h without any potential risk of C. perfringens germination and outgrowth. These findings will be of immediate use to the retail food service operations and regulatory agencies to ensure the safety of the cooked scrapple.
We conducted stabilization studies to determine the ability of Clostridium perfringens spores to germinate and grow during exponential cooling of a commercial formulation of pork scrapple. Scrapple was inoculated with a mixture of three strains of C. perfringens spores (NTCC 8238, NCTC 8239, and ATCC 10288), vacuum packaged, and reheated (20 min/93.3 degree C) in a circulating water bath. The cooked samples were cooled (30 sec) in an ice bath before being transferred to a programmable water bath to cool through the temperature range of 54.4 to 7.2C in 12, 14, or 21 h to simulate deviations from the required cooling time of 6.5 h. After cooling, the samples were analyzed to determine if growth from spores had occurred. The samples were plated onto tryptose-sulfite-cycloserine agar and incubated anaerobically at 37C for 48 h before counting the colonies. Minimal growth (less than 1.0 log) was observed during a 12- or 14-h cooling period. However, when the time to achieve 7.2C was extended to 21 h, C. perfringens spores germinated and grew from an inoculum of ca. 3.0 log to ca. 7.8 log CFU/g. Thus, scrapple must be cooled after cooking to 7.2C in 6.5 h, but for no more than 14 h, to prevent a food safety hazard from outgrowth of C. perfringens spores during cooling.