INFLUENCE OF pH ON Clostridium botulinum CONTROL BY SODIUM NITRITE AND SORBIC ACID IN CHICKEN EMULSIONS

The influence of hydrogen‐ion concentration on the effectiveness of sodium nitrite and/or sorbic acid to control Clostridium botulinum growth during elevated temperature abuse (27°C) of mechanically deboned chicken meat frankfurter‐type emulsions was examined. Toxin production, spore germination (loss of heat resistance) and outgrowth, residual nitrite levels, and total microbial growth (aerobic CFU) were determined at specified times during the incubation period. The effect of sorbic acid (0.2%), alone or in combination with nitrite (40, 156 μg/g), in significantly (p < 0.05) inhibiting spore germination, growth, and toxin production was pH dependent. This effect was not observed at pH values above 6.20 and it increased with decreasing pH. Inclusion of nitrite in the formulation increased the effective pH for sorbic acid inhibition of toxin production. The rapid rate of germination and outgrowth in both control and nitrite‐containing treatments was not influenced by pH in the range examined (5.93‐6.93). When sorbic acid was included in the formulation, there was a slower nitrite depletion during storage. This effect was also pH dependent and it was not observed at higher pH values (7.15). Total microbial growth was affected by decreasing pH, but not by the inclusion of nitrite and/or sorbic acid in the formulation.