3M Petrifilm Staph Express Count plate method for the enumeration of Staphylococcus aureus in selected dairy foods: collaborative study.
The 3M Petrifilm Staph Express Count plate method was compared with AOAC Official Method 975.55 for the enumeration of Staphylococcus aureus in selected foods. Five foods--ice cream, raw milk, yogurt, whey powder, and cheese--were analyzed for S. aureus by 12 collaborating laboratories. For each food tested, the collaborators received 8 blind test samples consisting of a control sample, a low inoculation level, a medium inoculation level, and a medium inoculation level with background flora, each in duplicate. The mean log10 counts for the methods were comparable for all 5 foods. The repeatability and reproducibility variances of the 24 h Petrifilm Staph Express Count plate method were similar to those of the 72 h standard method.
Silbernagel
Karen M
KM
rtech laboratories, PO Box 64101, St. Paul, MN 55164-0101, USA. kmsilbernagel@landolakes.com
Jechorek
Robert P
RP
Carver
Charles N
CN
Horter
Barbara L
BL
Lindberg
Kathryn G
KG
D000818:Animals; D002611:Cheese / Q000382:microbiology; D015169:Colony Count, Microbial / Q000295:instrumentation / Q000379:methods*; D003611:Dairy Products / Q000382:microbiology*; D007054:Ice Cream / Q000382:microbiology; D007753:Laboratories; D008892:Milk / Q000382:microbiology; D008894:Milk Proteins; D015203:Reproducibility of Results; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D000067816:Whey Proteins; D015014:Yogurt / Q000382:microbiology
D008894:Milk Proteins; D000067816:Whey Proteins