The level of contamination of commercially prepared convenience foods with the growth products of Staphylococcus aureus will be measured using a specific radioassay for the nuclease produced by this pathogen, while concurrently measuring the numbers and kinds of fecal and oral streptococci present in the foods and testing for the presence or absence of human mycoplasma species. We will assess the utility of tests based on the dehydrogenase, arginine dihydrolase, urease, and nucleolytic activities of mycoplasma for rapid detection of these organisms in foods.