Enzyme-linked immunosorbent assay for detection of staphylococcal enterotoxins in foods.
An enzyme-linked immunosorbent assay (ELISA) was developed for detection of staphylococcal enterotoxins in foods. The "double-antibody sandwich" protocol combines parts of several procedures reported previously. Horseradish peroxidase was conjugated to antibody specific for an enterotoxin, and the antibody-enzyme conjugate was assayed with a 2,2'-azino-di-(3-ethylbenzthiazoline sulfonic acid)-H2O2 substrate solution. Enterotoxins were added to a variety of foods that were representative of those implicated in staphylococcal food poisoning outbreaks. Extracts of the foods were assayed by the ELISA and radioimmunoassay. Enterotoxin levels below 1 ng/g of food were consistently detectable by the ELISA. These results compared favorably with those of the radioimmunoassay. Experiments confirmed the interference of protein A in double-antibody sandwich ELISAs. Although protein A interference has not been demonstrated to be a problem in food extracts, we suggest a screen for protein A interference in which immunoglobulin G from nonimmunized rabbits is used. All of the known staphylococcal enterotoxins could be detected by this method. Analysis of a food product for entertoxin by the ELISA can be completed in an 8-h working day.
D000818:Animals; D004768:Enterotoxins / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D005506:Food Contamination; D008460:Meat; D011863:Radioimmunoassay; D013205:Staphylococcal Protein A; D013211:Staphylococcus aureus; D013552:Swine
D004768:Enterotoxins; D013205:Staphylococcal Protein A; C026066:enterotoxin A, Staphylococcal