Quantitative risk assessment of microbial sampling effectiveness

Sampling as a means of assuring food safety can be analyzed by quantitative risk assessment. A computer simulation was performed in which liquid raw material with varying levels of contamination (-1 to -6 log CFU/ml) was converted into a food by a process that causes a mean log reduction of 5 log CFU/ml. Sampling before and after processing was simulated to determine if the food met the microbial quality standards of the product and to determine when sampling was more effective. Sampling the raw material was more useful than sampling the finished food product, because the levels of contamination were lower and harder to detect after processing. Sampling many batches of the product over time gave a clear idea of the contamination levels in the raw material. Sampling was least effective when contamination levels were moderate to low, though certain pathogens could still cause outbreaks of food-borne illness at these levels.