Detection of Enterotoxins Produced by Taphylococcus Aureus in Foods
Enzyme-linked Immunosorbent Assay (Elisa) Using the Tecra Kit

Laboratory Procedure MFLP-68
April 1998

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Health Protection Branch
Ottawa

M. Akhtar
Microbiology Research Division
Bureau of Microbial Hazards, Food Directorate
Postal Locator: 2204A2
Ottawa ON K1A 0L2

1. Application

This method is designed for the direct screening of foods and food ingredients for the presence of any of seven staphylococcal enterotoxins (SET) at a sensitivity of ≥ 1 ng/mL. Toxins detected include

A,B,C ₁,C ₂,C ₃,D and E. Since this method does not determine the specific toxin type produced, Laboratory

Procedures MFLP-67 or MFLP-69 should be used if type confirmation of positive results is required. This revised method replaces MFLP-68 dated October 1993.

2. Principle

The SET Visual Immunoassay is designed to provide a rapid, sensitive and specific test for the detection of staphylococcal enterotoxin. The Enzyme-linked Immunosorbent Assay (ELISA) is performed in a "sandwich" configuration (11.1). High affinity "capture" antibodies to the toxins are adsorbed onto the surface of the

Removawells®. If staphylococcal enterotoxins are present in the sample they will be captured by the adsorbed antibodies. All other material in the sample is washed away. The sandwich is completed by the addition of enzyme-labelled antibodies (ie. conjugate) specific for staphylococcal enterotoxins. The enzyme's presence is in turn detected when it converts the colourless substrate to a green colour.

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3. Definition of Terms

See Appendix A of Volume 3.

4. Collection of Samples

See Appendix B of Volume 3.

5. Materials and Special Equipment

1) SET-visual immunoassay kit for enterotoxins A,B,C ₁,C ₂,C ₃,D and E. The kit is available from International Bioproducts, Inc., 14796 NE 95th Street, Redmond, WA 98052 USA (phone: 800-745- 1044; Fax: 206-881-6880).