Studies on the Application of Enzyme Immunoassays for the Fusarium Mycotoxins Deoxynivalenol, 3‐Acetyldeoxynivalenol, and Zearalenone

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Abstract
Summary: Polyclonal antisera against zearalenone (ZEA) were produced in rabbits after immunization with ZEA‐oxime coupled to human serum albumin. Using these antibodies and a ZEA‐oxime‐horseradish peroxidase conjugate in a competitive direct enzyme immunoassay (EIA), the detection limit for ZEA was 70pg/ml. The relative cross‐reactivities of the assay with ZEA, α‐zearalenol, β‐zearalenol, zearalanone, α‐zearalanol, and β‐zearalanol, respectively, were 100%, 37.3%, 7.2%, 59.2%, 5.3%, and 3.9%, respectively. This EIA and two EIAs for deoxynivalenol (DON) and 3‐acetyldeoxy‐nivalenol(3‐AcDON) (Usleber et al., 1991) were used to analyze wheat samples. The limits of determination for DON, 3‐AcDON, and ZEA in wheat were 200 ppb, 50ppb, and 20ppb, respectively. The analysis of reference materials (wheat flour) containing DON by EIA showed good agreement with the nominal values. The EIA for ZEA was in addition used to analyze biological fluids, obtained during a feeding trial. Two lactating cows were administered 25 mg and 100 mg ZEA per day, respectively, over a period of 6 days. Serum, milk, urine, and feces were assayed in the ZEAEIA with and without sample treatment with β‐glucuronidase prior to the analysis. Maximum toxin levels (ZEA‐equivalents) found in milk were 0.4 and 1.2 ppb (glucuronides). The toxin concentration in milk decreased rapidly after the last toxin administration. In the urine, maximum levels of toxin‐glucuronide conjugates were 23 ppb and 24 ppb, respectively. The serum toxin levels corresponded to those found in milk. In the feces, mean values were 150 ppb and 500 ppb, respectively, no conjugated toxins were found in feces.