Statistics of Sampling for Microbiological Testing of Foodborne Pathogens

A sampling plan is part of a process to assess the acceptability of a batch of product against some criterion. At a minimum, a sampling plan involves specification of the number of samples to be drawn and tested from a lot and a criterion (or criteria) that must be satisfied to consider the entire batch as acceptable for sale or other specified uses.

In this text, the main interest is the assessment of the microbiological safety of foods, but the same considerations discussed in this chapter apply equally to assessment of microbiological quality. Even with the widespread implementation of preventative strategies such as hazard analysis and critical control point (HACCP) and related food safety management strategies, there are still many situations in which food safety assurance mainly relies on microbiological testing. End product testing might be needed in some circumstances, for example, when there are no critical control points in a process (e.g., raw or minimally processed ready-to-eat foods) or when the history of a product is unknown. Equally, food safety objectives and performance objectives (International Commission on Microbiological Specifications for Foods, 2002; Anonymous, 2005) may nominate microbiological criteria to be met.