Deoxynivalenol in commercial beer - screening for the toxin with an indirect competitive ELISA.

Antibodies specific for deoxynivalenol (DON) were prepared by immunizing rabbits with a deoxynivalenol-hemiglutaryl-HSA conjugate. The antibody showed cross-reactivity with DON, 15a-acetyl-DON (15-Ac DON), and 3a-acotyl-DON (3-Ac DON) of 100%, 216%, and 260%, respectively. No cross-reactivity was observed against 20 further trichothecenes of the A-, B-, and C-type. An indirect competitive ELISA procedure was set up for the detection of DON in liquid matrices occurring in the brewing process, Including beer. ELISA was sensitive down to 3.8 ng/mL. Detection limit for DON in tenfold diluted beer was 50 ppb. Recovery of the toxin in spiked beer was 45%, 77%, and 83% at toxin levels of 50; 500; and 1,000 ppb, respectively. ELISA results corresponded quite well with HPLC data. 196 commercial beers from several German breweries, including 36 gushing-positive samples, were assayed for DON. Screening revealed toxin levels from not detectable to 569 ppb. 69% of the gushing beers had marked levels of DON. 37% of the gushing-negative beer samples contained DON in detectable amounts with a maximum content of 172 ppb. Wheat beers had significantly higher DON-contents than beers derived from barley. Concentration of the toxin was significantly higher in gushing beers than in nongushing beers from both cereal sources.