Analysis, occurrence and control of Ochratoxin A residues in Danish pig kidneys

In Denmark, porcine kidneys displaying macroscopic lesions of mycotoxic nephropathy are analysed for Ochratoxin A and the carcass condemned if the concentration exceeds 25 micrograms/kg. Since late 1982 these analyses have been conducted centrally. The reliability of the one-dimensional thin layer chromatographic method is discussed and results from an interlaboratory comparison are presented. From 1980 to 1984 there has been an overall decline in the rate of ochratoxicosis, interrupted in 1983 by a major increase geographically located in the northern half of Jutland. During that year 7639 kidneys were examined; 3% contained more than 150 micrograms/kg and 29% more than 25 micrograms/kg Ochratoxin A, corresponding to a condemnation rate of 15 per 100 000 slaughterings. The early stage of the increased incidence was characterized by kidneys with extremely high levels of the toxin; later most of the samples were negative or near-negative, as affected pigs were presumably fed a toxin-free diet before slaughtering. The efficacy of the control program is discussed in view of the 1983 data.