Thiabendazole [2-(4-thiazolyl)-1H-benzimidazole,TBZ] is used as a preharvest or postharvest fungicide on pome fruits, citrus, bananas, potatoes, and several other commodities. An enzyme-linked immunosorbent (ELISA) method was developed which uses monoclonal antibodies that bind thiabendazole. The antibodies were elicited using the hapten 5-succinamido-2-(4-thiazolyl)benzimidazole. Aqueous buffers or water is adequate for extraction of the TBZ, and the method can be completed, without access to sophisticated laboratory equipment, within 4h. Results were validated by comparison to a method employing chromatographic fractionation with UV detection. The ELISA method using aqueous extraction of apple or potato peel has a limit of detection of <0.2 ppm. Since U.S. federal tolerances for residues of TBZ in potatoes and apples are both 10 ppm, this rapid screening test has sufficient sensitivity for regulatory monitoring of residues. In addition, the ELISA could serve as a quality control procedure for dipping or spraying operations.
