Chapter 25 : Practical Sampling Plans, Indicator Microorganisms, and Interpretation of Test Results from Trouble-Shooting

Abstract:

Food service can be defined as those entities responsible for meals prepared outside the home. Included in this definition are restaurants, schools, catering companies, hospital cafeterias, and commercial or institutional kitchens operating within other venues. Food service distributors typically supply foods in bulk to these entities. Consequently, these institutions have a need to understand and implement appropriate microbiological specifications, such as sampling plans, rapid testing, and interpretation of data. In food service operations as well as the rest of the food industry, the question, ‘‘How many samples should I require be taken and tested?’’ is an important question that is frequently asked and is particularly important in the context of establishing supplier microbiological criteria. Related to that question are deeper considerations and questions including the following: (i) Is the target organism likely to be evenly distributed in my food sample? and (ii) if the organism is evenly distributed, does that mean one sample is enough? Another critical concern relates to interpretation of results, particularly as they relate to retesting, and addresses the questions, ‘‘Is retesting an appropriate means to verify the accuracy of my test data? And, if so, when is it appropriate?’’ All these issues are addressed in this chapter.