Thermal Resistance of Spores from pH, Elevating Strains of <i>Bacillus licheniformis</i>

Abstract

ABSTRACT The thermal resistance of Bacillus licheniformis spores from strains originally isolated from home‐canned tomatoes was examined. In tomato puree at pH 4.4, D 95 and D 100 values of 4.5 and 2.0 min, respectively, were obtained. The z value was 14.9 C°. The D 95 in pH adjusted tomato puree increased at the rate of 50% per pH unit over the range pH 4–5.5. The D 95 in pH 7.2 buffer was 7.8 min. The B. licheniformis spores could survive the USDA raw pack process for home‐canned tomatoes and elevate the pH to greater than 5.2 under aerobic but not anaerobic conditions.