Production of aflatoxin B1 and B2 by Aspergillus flavus in inoculated wheat using typical craft beer malting conditions

Abstract

The production of aflatoxin (AF) B1and B2was determined during malting of wheat grains artificially con-taminated with a toxigenicA.flavusstrain (CCDCA 11553) isolated from craft beer raw material. Malting wasperformed in three steps (steeping, germination and kilning) following standard Central European Commissionfor Brewing Analysis procedures. AFB1and AFB2were quantified in eleven samples collected during the threemalting steps and in malted wheat. Both, AFB1and AFB2were produced at the beginning of steeping anddetected in all samples. The levels of AFB1ranged from 229.35 to 455.66μg/kg, and from 5.65 to 13.05μg/kgfor AFB2. The AFB2increased during steeping, while no changes were observed in AFB1.Otherwise, AFB1de-creased during germination and AFB2did not change. AFB1and AFB2increased after 16 h of kilning at 50 °C anddecreased at the end of kilning, when the temperature reached 80 °C. The levels of AFB1wheat malt were lowerthan those detected in wheat grains during steeping; however, levels of both AFB1(240.46μg/kg) and AFB2(6.36μg/kg) inAspergillusflavusinoculated wheat malt exceeded the limits imposed by the regulatory agenciesfor cereals and derived products.