Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/18/2010
Publication Date: 4/1/2010
Citation: Singh, A., Korasapati, N.R., Juneja, V.K., Thippareddi, H. 2010. Effect of phosphate and meat (pork) types on the germination and outgrowth of Clostridium perfringens spores during abusive chilling. Journal of Food Protection. Vol.73:879-887. 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 pork products to remain pathogen-free and provide vital data for performing risk assessment on cooked meat. We determined that cooling times for ground pork after heat processing can be extended to 21 h by incorporation of tetrasodium pyrophosphate and/or sodium acid pyrophosphate to reduce the 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 foods.
Technical Abstract: The effect of blends of phosphates and the pork meat type (pale, soft and exudative, PSE; normal; and dark, firm and dry, DFD) on the germination and outgrowth of Clostridium perfringens during abusive exponential chilling times was evaluated. Two different phosphates, tetrasodium pyrophosphate (TSPP) and sodium acid pyrophosphate (SAPP; from two different sources, SAPP - 1 and SAPP - 2) were used. The pork loins representing each meat type were ground (1/8 in. plate), and the three phosphate blends (SAPP -1 + SAPP - 2, TSPP + SAPP - 1 or TSPP + SAPP - 2) were added (0.3% total, equal proportions of 0.15% each type) along with salt (1.0%). The pork was then mixed with a three-strain C. perfringens spore cocktail to obtain a final concentration of ca. 2.0 - 2.5 log spores/g. The inoculated product was heat shocked for 20 min at 75C and chilled exponentially from 54.4 to 4C in 6.5, 9, 12, 15, 18 or 21 h. In control samples (PSE, normal and DFD), the increase in C. perfringens population was < 1 log CFU/g within 6.5 h chilling time, with longer chilling times resulting in greater increases. C. perfringens population increases of 5.95, 4.73 and 5.95 log CFU/g meat were observed in normal, PSE and DFD pork, respectively during 21 h abusive chilling time. The combination of SAPP - 1 + SAPP - 2 was effective in inhibiting C. perfringens population compared to other treatments. The types of phosphate and their blends, and the meat type affect the germination and outgrowth of C. perfringens spores in cooked pork during abusive chilling times.