Development and validation of an ELISA kit for the detection of Staphylococcus aureus enterotoxin A, B, C1, C2, C3, D, E from food samples

Staphylococcus aureus (S. aureus) is a significant food-borne pathogen that poses a threat to human health. The classical serotypes staphylococcal enterotoxin (SE) A, B, C1, C2, C3, D, E produced by S. aureus are the primary cause of its food-borne pathogenic toxicity. Therefore, establishing a highly sensitive, rapid, robust, high-throughput detection method for the total amount of classical serotypes of SEs is crucial for food safety and public health. This study prepared 10 rabbit polyclonal antibodies and 40 mouse monoclonal antibodies targeting SEA, SEB, SEC1, SEC2, SEC3. Upon identifying the optimal antibody pairs through square array method and optimization, a sandwich ELISA kit for the detection of SEs (SEA, SEB, SEC1, SEC2, SEC3, SED, SEE) was developed, with respective limits of detection at 0.169-0.688 ng/mL. In addition, this sandwich ELISA kit could detect SEs in raw cow milk, pasteurized milk, fermented milk, milk powder, whey powder, rice, raw pork, and canned beef samples with coefficients of variation below 7%. Meanwhile, this sandwich ELISA kit was stable at 4°C for one-year storage. The study fills a research gap in the detection of the total amount of classical serotypes of SEs.