Immunoaffinity clean-up and direct fluorescence measurement of aflatoxins B1 and M1 in pig liver:: Comparison with high-performance liquid chromatography determination

An improved analytical method for aflatoxin B-1 ( AFB(1)) and aflatoxin M-1 ( AFM(1)) determination in pig liver is described, using an aqueous methanol extraction, an immunoaffinity column clean-up step and a direct fluorometric measurement for toxin detection and quantification. A detection limit of 1.0 mu g kg(-1) was achieved for AFB(1) and AFM(1). Mean recoveries of 80.7 +/- 9.0% for AFB(1) spiked at 1.0-9.7 mg kg(-1) levels and of 76.7 +/- 6.6% for AFM1 spiked at 1.0-5.5 mg kg(-1) levels were obtained. Recovery data for spiked samples were statistically compared with those obtained by the same extract using classical reversed-phase high-performance liquid chromatography ( RP-HPLC) with fluorescence detection, showing a significant correlation ( p <= 0.05) for both aflatoxins. Both procedures were applied to the analysis of 50 pig livers, collected from 10 farms in the north of Italy. All the samples showed a contamination level lower than 1.0 mu g kg(-1) for AFB(1) and one liver sample has shown an AFM(1) contamination greater than 1.0 mg kg(-1). The direct fluorometric procedure is particularly suitable for food manufacturers and control laboratories where quick procedures are mainly required for food quality control as well as for diagnostic and research purposes.