Development and evaluation of sandwich ELISA for detection and quantification of staphylococcal enterotoxin‐A in food

Staphylococcus aureus is an opportunistic zoonotic pathogen which secretes 24 different types of enterotoxins (SEs) and enterotoxin‐like (SEls) proteins. Classical enterotoxins (SEA–SEE) are responsible for >95% of food poisoning outbreaks, of which SEA alone is responsible for >75% of them. This study was undertaken to develop a sandwich enzyme‐linked immunosorbent assay (ELISA) for sensitive, specific, and quantitative detection of staphylococcal enterotoxins‐A in food. Optimization of sandwich ELISA was attempted in two ways: rabbit polyclonal anti‐SEA as a capture antibody and mouse monoclonal anti‐SEA as a detector antibody, and vice versa. In the optimization of sandwich ELISA, mouse monoclonal anti‐SEA as a capture antibody and rabbit polyclonal anti‐SEA as a detector antibody yielded the highest sensitivity of 0.5–0.75 ng mL−1. The developed assay was found to be highly specific and exhibited equivalent sensitivity to a commercial kit. The developed sandwich ELISA may be utilized for the detection of staphylococcal enterotoxin‐A in food as a cheap alternative to available commercial kits. The developed sandwich ELISA may be useful for microbiological quality assurance of foods, especially in resource‐limited developing countries. Test for ensuring Microbiological Safety of Food