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

Polyclonal antibodies were produced for Ochratoxin A (OA) by injecting OA-b ovine serum albumin (BSA) conjugate subcutaneously at multiple sites into a New Zealand White inbred rabbit. Antiserum could be used at a dilution exc eeding 1:100 000 in an indirect competitive enzyme-linked immunosorbent ass ay (ELISA), and detected OA concentrations up to 0.1 ng/mL. The 50% inhibit ion binding (I-50) of OA was 5 ng/mL. Antibodies did not react with ochrato xin B, coumarin, 4-hydroxycoumarin, L-phenylalanine, and aflatoxin B1. OA c ontamination in chilies (Capsicum annum L.) collected from commercial marke ts 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% w ith a standard deviation of <10%. Of 100 chili samples tested, 26 were foun d to contain over 10 <mu>g/kg of OA. In 12 samples the OA concentration var ied 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 firs t record in India of OA in chilies, a major component of cooked foods in th is country, and it is noteworthy that OA contamination exceeded the permiss ible limit for human consumption of less than 20 mug/kg in over 26% of the market samples tested.