Development and evaluation of sandwich ELISA for detection and quantification of Staphylococcal enterotoxin-A in food

Abstract Purpose Staphylococcus aureus is an opportunistic zoonotic organism which secretes around 23 different types of enterotoxins. Classical enterotoxins (SEA, SEB, SEC, SED and SEE) are responsible for >95 % of food poisoning outbreaks of which SEA alone is responsible for >75% of them. The present study was undertaken to develop sandwich ELISA forsensitive, specific and quantitative detection of Staphylococcal enterotoxins-A in food samples. Methods Optimization of sandwich ELISA was attempted in two ways. In first, rabbit polyclonal anti-SEA was used as capture antibody and mouse monoclonal anti-SEA as detector antibody, in second, mouse monoclonal anti-SEA was used as capture Antibody and rabbit polyclonal anti-SEA as detector antibody. Results In the optimization of sandwich ELISA, mouse monoclonal anti-SEA as capture antibody and rabbit polyclonal anti-SEA as detector antibody yieldedhighest sensitivity of 0.5-0.75 ng ml-1. The developed assay was found to be highly specific and having equivalent sensitivity to available commercial kits. Conclusion The developed sandwich ELISA may be utilized as a sensitive, specific and quantitative test for detection of Staphylococcal enterotoxin-A in food samples. The developed ELISA may serve as a cheap alternative to commercial kits which need importation and therefore are relatively costly. The sandwich ELISA developed may be useful for microbiological quality assurance of foods specially in developing countries.