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A simple protocol was devised for the routine immunochemical assay of zearalenone in corn. Essential features of the procedure were (1) blending corn in methanol-phosphate-buffered saline-dimethylformamide with a volume ratio of 70:29:1, (2) filtering of the blended sample, and (3) analysis of filtrate by competitive direct enzyme-linked immunosorbent assay (ELISA). Average ELISA recoveries of zearalenone in com spiked at levels of 57,151, and 307 Mg/kg were 50,119, and 123%, respectively. Mean interwell and interassay coefficients of variation for the spiked samples were 21.6 and 5.9%, respectively. The ELISA cross-reacted with -zearalenol and to a lesser extent with /3-zearalenol, -zearalanol, and d-zearalanol. Levels of zearalenone detected in three naturally contaminated samples were comparable to those determined by liquid chromatography. The results suggested that the procedure was suitable for rapid semiquantitative screening of zearalenone in corn at levels considered to be at the threshold required for swine hyperestrogenism.(fraction V, fatty acid free) (BSA), chicken egg albumin (ovalbumin, grade III), 2,2-azinobis(3-ethylbenz-

Chapaties made from different wheat varieties differ ln puffing and textural characteristics. These differences have been found to be related to the relative quantities of gliadlns, glutenins and residue proteins in respective glutens. Wheat varieties having about equal quantities of gliadins, glutenlns and residue proteins give fully puffed soft and pliable chapaties. Wheat varieties having more of residue protein give leathery chapaties and varieties having more of gliadin give relatively stiff chapaties. Applications of Warner-Bratzler shear press for evaluating chapati texture is discussed.

A competitive indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection of zearalenone, an estrogenic mycotoxin. Zearalenone was converted to zearalenone-6'-carboxymethyloxime and conjugated to bovine serum albumin and poly-L-lysine for use as immunogen and solid-phase marker, respectively. Immunization of rabbits with the bovine serum albumin conjugate resulted in zearalenone antibody titers of 20,480 in 11 weeks. A competitive indirect ELISA was conducted by simultaneously incubating zearalenone with zearalenone antiserum over zearalenone-6'-carboxymethyloxime poly-L-lysine solid phase and then determining the bound rabbit immunoglobulin with goat anti-rabbit peroxidase conjugate. Response range for zearalenone in the resulting competition curve was between 1 and 50 ng/ml. Reactivities of this antiserum for a-zearalenol, P-zearalenol, a-zearalanol, and P-zearalanol were, respectively, 50, 12, 6, and 3% of that found for zearalenone. By using the competitive indirect ELISA, zearalenone was detectable in methanol-water extracts of corn, wheat, and pig feed samples. * Corresponding author. t Article no. 11566 from the Michigan State Agricultural Experiment Station.

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A simple procedure was devised for the routine screening of aflatoxin B1 (AFB1) in peanut butter using enzyme-linked immunosorbent assay (ELISA). Peanut butter samples (5 g) were artificially contaminated with AFB1 and extracted by blending with 25 ml of 55% methanol and 10 ml of hexane. The extract was filtered and aqueous filtrate analyzed by a direct competitive ELISA. Recovery of AFB1 added to peanut butter samples ranged from 85 to 112%, with an average inter-well coefficient of variation of 18.4%. The inter-assay coefficient of variation was 22.7%. Using this procedure, only 3 of 63 commercial samples of peanut butter had detectable levels (>5.0 μg/kg) of AFB1.