Production of polyclonal antibodies against ochratoxin A and its detection in chilies by ELISA

Polyclonal antibodies were produced for Ochratoxin A (OA) by injecting OA-bovine serum albumin (BSA) conjugate subcutaneously at multiple sites into a New Zealand White inbred rabbit. Antiserum could be used at a dilution exceeding 1:100 000 in an indirect competitive enzyme-linked immunosorbent assay (ELISA), and detected OA concentrations up to 0.1 ng/mL. The 50% inhibition binding (I(50)) of OA was 5 ng/mL. Antibodies did not react with ochratoxin B, coumarin, 4-hydroxycoumarin, L-phenylalanine, and aflatoxin B1. OA contamination in chilies (Capsicum annum L.) collected from commercial markets and cold storage units was determined. The mean recoveries from OA-free chilies spiked with 1 to100 mug of OA per kg of chili sample were 90-110% with a standard deviation of <10%. Of 100 chili samples tested, 26 were found to contain over 10 <mu>g/kg of OA. In 12 samples the OA concentration varied from 10 to 30 mug/kg, in 10 samples from 30 to 50 mug/kg, in 3 samples from 50 to100 mug/kg, and in one sample it was 120 mug/kg. This is the first record in India of OA in chilies, a major component of cooked foods in this country, and it is noteworthy that OA contamination exceeded the permissible limit for human consumption of less than 20 mug/kg in over 26% of the market samples tested.