Mycoflora and Aflatoxin / Zearalenone Contamination of Animal Feed and Silage Intended to Dairy Cattle Feed

V.A. ALONSO,; M.L. GONZÁLEZ PEREYRA, ; C.M. PEREYRA, ; S. PEIRANO, ; C.A.R. ROSA,; A.M. DALCERO, ; L.R. CAVAGLIERI, ; S.M. CHIACCHIERA

Estambul, Turquía

Congreso; X International IUPAC Symposium. Mycotoxins and Phycotoxins; 2007

Mycotoxins are a serious concern for feed industry since consumption of contaminated commodities may cause mycotoxicoses. Aflatoxins, produced by Aspergillus spp. have carcinogenic, teratogenic and mutagenic effects and are hazard for human and animal health. Aflatoxin B1 (AFB1) is the most toxic followed by AFM1. In dairy cattle, passage of AFB1 to milk as AFM1 is straightly related to milk production. The aim of this work was to detect and quantify AFB1 and zearalenone in feed intended for dairy cattle.  Finished feed and silage samples were collected. Total fungal counts and natural incidence of fungal genera and toxigenic Aspergillus, Penicillium y Fusarium species were performed on dichloran rose bengal chloranphenicol agar (DRBC), dichloran glycerol agar 18% (DG18) and Nash-Snyder culture media. Aflatoxins and zearalenone natural contamination was determined by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Total fungal counts were higher than 1 x 104 UFC g-1. Aspergillus spp. and Penicilliun spp. showed the highest incidence among toxigenic genera, whereas A. flavus, A. fumigatus and F. verticillioides were the most prevalent species. No zearalenone-producing species were found. A low percentage of samples showed aflatoxin contamination. Even though, levels detected were higher than recommended limits (5 ppb) for dairy cattle. These results suggest a potential exposition of human population – mainly children – to AFM1 in milk and by-products.