Effect of phosphate and meat (pork) types on the germination and outgrowth of Clostridium perfringens spores during abusive chilling.

The effect of phosphate blends and 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 phosphates were used: tetrasodium pyrophosphate (TSPP) and sodium acid pyrophosphate (SAPP; from two different sources, SAPP(1) and SAPP(2)). The pork loins representing each meat type were ground (1/8-in. [0.3-cm] plate), and one of the three phosphate blends (SAPP(1)+SAPP(2), TSPP+SAPP(1), or TSPP+SAPP(2)) was added (0.3% total, equal proportions of 0.15% each type) 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 to 2.5 log spores per g. The inoculated product was heat shocked for 20 min at 75 degrees C and chilled exponentially from 54.4 to 4 degrees C in a period of 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 the 6.5-h chilling period, and longer chilling times resulted in greater increases. C. perfringens population increases of 5.95, 4.73, and 5.95 log CFU/g of meat were observed in normal, PSE, and DFD pork, respectively, during the 21-h abusive chilling period. The combination of SAPP(1)+SAPP(2) was more effective than the other treatments for inhibiting C. perfringens. The types of phosphate and their blends and the meat type affected the germination and outgrowth of C. perfringens spores in cooked pork during abusive chilling periods.