THERMAL INACTIVATION OF CLOSTRIDIUM-PERFRINGENS VEGETATIVE CELLS IN-GROUND BEEF AND TURKEY AS AFFECTED BY SODIUM PYROPHOSPHATE

The heat resistance (55-65 degrees C) of Clostridium perfringens veget ative cells in ground beef and turkey that included 0, 0.15 or 0.3% (w /w) sodium pyrophosphate (SPP) was assessed in bags heated using a wat er bath. The surviving cell population was assayed on tryptose-sulfite -cycloserine agar. The decimal reduction (D)-values in beef that inclu ded no SPP were 21.6, 10.2, 5.3, and 1.6 min at 55 57.5, 60, 62.5 degr ees C, respectively; the values in turkey ranged from 17.5 min at 55 d egrees C to 1.3 min at 62.5 degrees C. Addition of 0.15% SPP resulted in concomitant decrease in heat resistance as evidenced by reduced bac terial D-values. The D-values in beef that included 0.15% SPP were 17. 9, 9.4, 3.5, and 1.2 min at 55, 57.5, 60, and 62.5 degrees C, respecti vely; the values in turkey ranged from 16.2 min at 55 degrees C to 1.1 min at 62.5 degrees C. The heat resistance was further decreased when the SPP level in beef and turkey was increased to 0 3%. Heating such products to an internal temperature of 65 degrees C for 1 min killed > 8 log(10) cfu g(-1). The z-values in beef and turkey for all treatment s were similar, ranging from 6.22 to 6.77 degrees C. Thermal death tim e values from this study should assist institutional food service sett ings in the design of thermal processes that ensure safety against C. perfringens in cooked beef and turkey. (C) 1998 Academic Press.