Mycobiota and Mycotoxin Content of Cereal Flours from a Serbian Market ^†

Abstract

Altogether, 39 cereal flour samples taken from a Serbian market were analyzed for mycobiota and mycotoxin content, among which were six Triticum aestivum specimens, five Triticum dicoccum specimens, four Hordeum vulgare specimens, five Fagopyrum esculentum specimens, three Secale cereale specimens, five Triticum spelta specimens, four Avena sativa specimens, two Oryza sativa specimens, two Zea mays specimens, and one specimen each of Panicum miliaceum, Triticum monococcum, and Triticum turgidum ssp. turanicum. To determine the mycobiota content using dilution techniques, the flour samples were transferred to a non-selective DG18 nutrient. The number of coloniforming units (CFU/g) varied from less than 100 (in the case of five samples, namely, two O. sativa, and one specimen each of S. cereale, H. vulgare, and T. aestivum) to as high as 5000 CFU/g (S. cereale), 6000 (A. sativa), 11,000 (T. aesticum), and 40,000 (Z. mays). The identification of fungal genera and species was performed on Czapex-Dox Agar and Potato dextrose Agar on the basis of the isolates’ colony characteristics and the morphology of the examined reproductive organs. The isolated fungi belonged to the following genera: Aspergillus, Penicillium, Alternaria, and Fusarium. Species from these genera are well-known mycotoxin-producing fungi. Among the identified species were A. candidus, A. flavus, A. carbonarius, A. ochraceus, A. oryzae, P. solitum, P. citrinum, P. griseofulvum, P. brevicompactum, A. alternata, F. avenaceum, and F. graminearum. The mycotoxin content was determined via the ELISA technique using Eurofins Technologies Hungary KFT kits for aflatoxin B1, deoxynivalenol, total aflatoxins, ochratoxin A, and zearalenone. In the case of eighteen samples, the total aflatoxin content was above the limit of detection, and seven of these samples were contaminated with aflatoxin B1, eight were contaminated with ochratoxin A, two were contaminated with dexynivalenol, and one was contaminated with zearalenon. Two samples of T. aestivum were contaminated with one or more toxins (33%), and the number of samples contaminated three for T. dicoccum (60%), one for H. vulgare (25%), four for F. esculentum (80%), one for S. cereale (33%), two for T. spelta (40%), three for A. sativa (75%), two for O. sativa (100%), two for Z. mays (100%), one for P. miliaceum (100%), one for T. monococcum (100%), and one for T. turgidum ssp. turanicum (100%).