Comparison of selective media for the enumeration of sublethally heated food-poisoning strains of Staphylococcus aureus

Abstract

Staphylococcus aureus strains (19 food-poisoning strains) were heated at 52C for 15 min in 100 mM potassium phosphate buffer. The sublethally heated organisms were enumerated on seven selective media commonly used for quantitating S. aureus. Compared to trypticase soy agar, Baird-Parker agar was the only medium which was satisfactory with all cultures tested. The remaining selective media gave unsatisfactory recoveries with one or more of the strains tested and are listed in the following order of decreasing acceptability: tellurite glycine agar, egg yolk azide agar, phenolphthalein phosphate agar with polymyxin, mannitol salt agar, Vogel Johnson agar.