Occurrence of mycotoxins in animal feeds.

A total of 1120 grain samples of oats, wheat, rye, barley, and maize, delivered for processing of mixed feeds for animals, were collected during the years 1975 to 1979 from commercial feed mills located throughout Poland. In addition, 625 samples of the commercially mixed feeds and protein concentrates were collected during 1976. For the mycotoxin survey, 751 laboratory samples were chosen at random and analyzed. When applying confirmatory tests neither aflatoxins B1, B2, G1, G2 nor sterigmatocystin, zearalenone, or ochratoxin B were found to be present in any of the samples of barley, wheat, rye, or oats. Aflatoxins were detected in about 4% of the maize samples. The presence of ochratoxin A in the range of 2 to 200 micrograms/kg was evident in 9% of the grain samples. The commercially mixed feeds were found to be more contaminated with mycotoxins than were the grains. The aflatoxins were confirmed in about 13% of the samples of mixed feeds. After the preliminary multimycotoxin analysis, out of 42 feed samples that could be suspected of containing ochratoxins, 32 failed to prove their presence. Similarly, out of 27 suspected feed samples, zearalenone was found only in one (0.5%) sample. The lowest percentage of samples contaminated with mycotoxins was found in poultry mixed feeds (4%). The highest contamination occurred among the samples of swine rations, where 17% of the samples contained aflatoxins and 13% ochratoxins. The protein concentrates contained only aflatoxins. Out of 31 analyzed samples, aflatoxins were detected in 19 (61%) in concentrations ranging from 5 micrograms/kg to 500 micrograms/kg. In one sample, aflatoxin concentration (B1 + B2) reached 1140 micrograms/kg. Practical implications of the results are discussed in relation to animal and human safety.