3M™ Petrifilm™ Staph Express Count Plate Method for the Enumeration of Staphylococcus aureus in Selected Dairy Foods: Collaborative Study

Abstract

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.

Antimicrobial Agent against Methicillin-Resistant Staphylococcus aureus Biofilm Monitored Using Raman Spectroscopy

“…The MIC and MBIC of eugenol and vancomycin were added to the medium and incubated at 37 °C for 4 h at 180 rpm [ 30 ]. After incubation, Petrifilms were used to enumerate the efficacy of the antibiotics [ 31 ]. The samples were diluted 10 times, and 1 mL was inoculated on a 3M Petrifilm count plate and modified TSA and incubated at 37 °C for 24 h.…”

Efficacy of a quaternary ammonium compound in reducing coagulase‐positive staphylococcal colony counts in veterinary dermatology exam rooms following two cleaning instruction protocols

“…The 3M Petrifilm Flat Spreader was used to ensure even dispersal of the media on the plate creating a growth area of approximately 30 cm 2 . The plates were applied directly to the 10 surfaces and then immediately removed per product recommendations 15–18 . Sampling of irregular surfaces was achieved owing to the flexibility of the gel plate.…”

“…The plates were applied directly to the 10 surfaces and then immediately removed per product recommendations. [15][16][17][18] Sampling of irregular surfaces was achieved owing to the flexibility of the gel plate. Irregular surfaces were divided into two halves: the left-hand side was sampled before, and the right-hand side after, Protocol 2 disinfection.…”

“…This product was developed for use in industrial food safety settings to detect and quantify Staphylococcus aureus in foods. [15][16][17] The plates contain a modified Baird-Parker medium selective for S. aureus, that also can detect the Staphylococcus intermedius Group and S. hyicus, 18 which includes S. pseudintermedius, recognised as the most common cause of bacterial pyoderma in the dog. 19 3M Petrifilm Staph Express Disks subsequently are applied to the 3M plates to visualise coagulase-positive staphylococci (CoPS) which develop a DNase" pink halo" zone.…”

“…3M Petrifilm Staph Express Count Plates (3M plates) (3M; Saint Paul, MN, USA) present a selective, single‐step alternative to traditional culture methods for recovery of coagulase‐positive Staphylococcus spp. This product was developed for use in industrial food safety settings to detect and quantify Staphylococcus aureus in foods 15–17 . The plates contain a modified Baird–Parker medium selective for S. aureus , that also can detect the Staphylococcus intermedius Group and S. hyicus , 18 which includes S. pseudintermedius , recognised as the most common cause of bacterial pyoderma in the dog 19 .…”