Microbiological criteria are risk management metrics which are used to indicate the acceptability of a food, or the performance of either a process or a food safety control system following the outcome of sampling and testing for microorganisms at a specified point of the food chain.  The components of a microbiological criterion include the microbiological limit that is to be implemented, the testing method to be employed, the sampling plan (i.e., size and number of samples to be examined), and the actions to be taken when the microbiological limit is exceeded.

A microbiological criterion can be used either as a tool for verifying that other control measures have been applied effectively or as a means of directly identifying unacceptable lots: i.e. those not complying with an established limit.  Actions that are specified when the sampling plan indicates that the microbiological criterion is not being met may include, for example, preventing the release of the product into domestic or international trade. This tool

• focuses on the elimination of lots deemed unacceptable in accordance with the specified sampling plan;
• estimates the risk reduction that is obtained as a result of this removal of unacceptable product from the exposure pathway;
• explore the impact of two- and three-class sampling plans (including both presence/absence and concentration-based) in terms of the likelihood to detect and therefore reject product not meeting the microbiological criterion;
• Estimate the risk reduction associated with this removal of unacceptable product from the exposure pathway.