Staphylococcus aureus: Production of Extracellular Compounds and Behavior in Foods - A Review

Abstract

Growth of Staphylococcus aureus is accompanied by produc tion of such extracellular compounds as hemolysins, nuclease, coagulase, lipase, and enterotoxins. Enterotoxins that can cause food poisoning are produced by about one-third of thecoagulasepositive strains of S. aureus.Theenterotoxins area heterogeneous group of heat-stable, water-soluble, single-chain globular proteins having a molecular weight between 28,000 and 35,000 daltons. Production of enterotoxin by appropriate strains of S. aureus is affected by thenutritional quality andpHof the substrate, tempera ture, atmosphere, sodium chloride (and hence water activity), other chemicals, and competing microorganisms. Outbreaks of staphylococcal food poisoning most often are associated with processed red meats, poultry products (especially chicken salad), sauces, dairy products (especially cheeses), and custard- or cream-filled bakery products. Ham and associated products often are involved inas many as30% ofoutbreaks of staphylococcal food poisoning. Most outbreaks result from the combined effects of contamination of the food, often through unsanitary handling, with S. aureusand holding the food at the wrong temperature thus allowing growth and synthesis of enterotoxin by the pathogen.