MODELING LAG PHASE OF NONPROTEOLYTIC CLOSTRIDIUM-BOTULINUM TOXIGENESIS IN COOKED TURKEY AND CHICKEN BREAST AS AFFECTED BY TEMPERATURE, SODIUM LACTATE, SODIUM-CHLORIDE AND SPORE INOCULUM

The length of the lag phase (LP) of toxigenesis in commercially cooked turkey meat stored under vacuum was determined as affected by 0, 1.2, 2 and 3% sodium lactate (L), 0, 1 and 2% NaCl (S), spore (pool of non proteolytic B and E strains: B2, B17, B197, B706, E211, E250, E KA-2 a nd E Beluga) inoculum (I) of 10(-2) to 10(4), storage temperature (T) of 4, 8, 12, 16, 20 and 30-degrees-C and their interactions. The time from inoculation to the detection of first toxic sample was defined as LP. Using regression analysis the following model predictive of LP of C. botulinum toxigenesis in the cooked turkey breast was derived: LP) =-2.2877-0.1235(S)-0.2174(L)+0.4391(square-root T)+0.0204(square-root T) (I). The model explained 94.5% of the variation in results, in whic h square-root T was the most influential factor (65%), followed by L ( 21.2%), interaction of I and square-root T (4.9%) and S (3.4%). The mo del predicted LPs longer than those observed in 28.3% of the compariso ns, but only in 1% of the comparisons when the lower limit of the 90% confidence interval of LP was used. Similar trends on the effect of L on C. botulinum were observed in an inoculated chicken meat study. Thi s study demonstrated quantitatively that increasing L and S concentrat ions and lowering of T had a beneficial effect on delaying toxigenesis .