Prevalence of Escherichia coli and enterococci in a Thai frozen cooked chicken plant, and modeling of the cleaning and sanitizing procedure

Escherichia coli and contamination with enterococci in a cooked ready-to-eat chicken meat product and on processing environmental surfaces were determined. Environmental surfaces were divided into three zones according to the distance of the products. Contamination with enterococci was higher than with E. coli on the surfaces in all zones. E. coli was not detected in any product, whereas 11.1% to 16.7% of samples were adulterated by enterococci. Contamination was mostly found in the niches of surfaces that were difficult to clean and sanitize, which led to contamination of the surfaces of the product transfer conveyor. Mathematical models, parameterized with scrubbing times with 1% (v/v) Quorum Pink II HF detergent, the concentration of acetic acid and the contact times with 100 ppm chlorine were established to predict the probability for both groups of viable bacteria on the conveyor surfaces following the cleaning and sanitizing process. Predicted values were almost equal to actual values, although slightly lower, when models were tested to validate the cleaning and sanitizing procedure.