Statistical Modeling of D‐ and z ‐value of E. coli O157:H7 and pH in Apple Cider Containing Preservatives

The objective of this study was to model the heat resistance of E. coli O157:H7 in apple cider as a function of added sorbate, benzoate, and malic acid. Inactivation experiments were done at 47, 50, and 53 °C, and D and z values were calculated. Models for D 47 , D 50 , and D 53 showed that all 3 additives significantly decreased heat resistance. Furthermore, z‐values increased with addition of preservatives and low pH. Model predictions showed that at 50 °C, 5‐log reduction is attainable in a few minutes when the cider contains additives, while preliminary test results showed that at 20 °C, a 5‐log reduction could be obtained in about 90 min in cider with 0.1% sorbate, 0.1% benzoate, and 1% malic acid.