title: Most probable number method for isolation and enumeration of Staphylococcus aureus in foods: collaborative study.
abstract: Enumeration of Staphylococcus aureus in foods was collaboratively studied by comparing the present AOAC final action method, 46.062, which uses trypticase soy broth with 10% NaCl to a proposed replacement method which uses the same broth with 1% sodium pyruvate added. Fifteen collaborators analyzed uninoculated samples of milk, tuna salad, and ground turkey, as well as samples inoculated with low (10(2) cells/g), middle (10(4) cells/g), and high (10(6) cells/g) levels of S. aureus. The samples were frozen immediately to maintain the inoculated level of S. aureus in the food. A different strain of S. aureus was used for each food; heat-stressed S. aureus cells were used to inoculate the milk samples. The pyruvate-amended broth significantly (alpha = 0.05) increased enumeration of low, middle, and high levels of S. aureus from milk and ground turkey, and from tuna salad at middle and high levels. The pyruvate-amended media method has been adopted official first action to replace method 46.062.
mesh_terms: D000818:Animals; D002417:Cattle; D003470:Culture Media; D005399:Fishes; D005516:Food Microbiology; D008460:Meat / Q000032:analysis; D008892:Milk / Q000382:microbiology; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D014422:Turkeys
chemical_list: D003470:Culture Media