Visual screening with enzyme immunoassay for staphylococcal enterotoxins in foods: collaborative study

Area of Science:

• Food Science
• Microbiology
• Immunology

Background:

• Staphylococcus aureus enterotoxins are a significant cause of foodborne illness.
• Accurate and rapid detection methods are crucial for food safety surveillance.
• Existing methods may lack specificity or speed for routine food analysis.

Purpose of the Study:

• To evaluate an enzyme-linked immunosorbent assay (EIA) for detecting multiple serotypes of Staphylococcus aureus enterotoxins in various food matrices.
• To determine the sensitivity, specificity, and practicality of the EIA method for collaborative testing.
• To establish a reliable method for rapid foodborne pathogen toxin detection.

Main Methods:

• A collaborative study involving 15 participants tested foods spiked with Staphylococcus aureus enterotoxins (serotypes A-E).
• An enzyme-linked immunosorbent assay (EIA) using a polyclonal antibody double "sandwich" configuration with polyvalent antisera was employed.
• Food samples were homogenized, extracted, and analyzed using microtiter wells, enzyme conjugate, and substrate, with results read visually and spectrophotometrically.

Main Results:

• The EIA method demonstrated sensitivity and specificity in detecting Staphylococcus aureus enterotoxins in food samples.
• Positive results were indicated by a bluish-green color development, with absorbance readings above 0.200 considered positive.
• The method allowed for the rapid assay of enterotoxins without the need to differentiate between serotypes.

Conclusions:

• The developed enzyme-linked immunosorbent assay (EIA) provides a sensitive, specific, and rapid method for detecting Staphylococcus aureus enterotoxins in foods.
• This EIA method is suitable for routine food safety testing and has been adopted by AOAC INTERNATIONAL.
• The assay's ability to detect multiple serotypes simultaneously enhances its utility in foodborne illness investigations.