Staphylococcus Aureus
Background:
The growth of Staphylococcus aureus in foods presents a potential public health hazard since many strains of S. aureus produce enterotoxins that case food poisoning if ingested. Among the reasons for examining foods for S. aureus are:
1. To confirm that this organism may be the causative agent of foodborne illness
2. To determine whether a food or food ingredient is a potential source of enterotoxigenic staphylococci
3. To demonstrate post-processing contamination, which usually is due to human contact with processed food or exposure of the food to inadequately sanitized food-processing surfaces.
Foods subject to post-process contamination with enterotoxigenic types of S. aureus represent a significant hazard because of the absence of competitive organisms that normally restrict the growth of S. aureus and the growth of enterotoxnis.
Method
AOAC 2003.07, 2003.11-3M Petrifilm ISO Accredited
Media
3M Petrifilm equivalent to Baird-Parker Agar
Turn Around Time
2 Business Days
Sample Required
10 to 100 g or mL or 1 swab
Type of Test
Quantitative Plate Count Analysis
Reportable Units
CFU per gram or CFU per mL or CFU per cm2 depending on original sample matrix
Detection Limit
<10 CFU/g or <1 CFU/mL or <0.1 CFU/cm2 depending on original sample matrix
Analysis Description:
The Petrifilm Staph Express Count Plate is a sample-ready culture medium system which contains a cold-water-soluble gelling agent. The chromogenic, modified Baird-Paker medium in the plate is selective and differential for Staphylococcus aureus.
The sample is diluted with a buffer, blended, and an extracted amount is plated on the Petrifilm, many times in a serial dilution format. Inoculated Petrifilm are incubated at 35°C for 48 hours.
