Preparation of synthetic antigen and monoclonal antibody for indirect competitive ELISA of citrinin

Citrinin (CIT)-protein synthetic antigen was prepared by conjugating CIT with keyhole limpet hemocyanin by 1,4-butanediol diglycidyl ether. The ultraviolet and infrared spectrometry analyses indicated that CIT was conjugated with the carrier protein successfully. By fusion and cloning, a hybridoma cell line K2-F3 which stably secreted the highly specific monoclonal antibody (McAb) against CIT was obtained. The indirect competitive ELISA showed that the IC₅₀ value was 0.3 ng/mL and the limit of detection, 0.01 ng/mL. Cross-reactivity was less than 0.01% with four mycotoxins, aflatoxin B₁, ochratoxin A, zearalenone, deoxynilvalenol and three pigments, rubropunctatine, rubropunctamine, monascin. The mean recovery of citrinin from artificially contaminated red yeast rice was from 89 to 92%, with CVs from 6.8 to 9.0%. The ELISA developed in this study can accurately determine CIT in artificially contaminated red yeast rice.