On ochratoxin A and fungal flora in Polish cereals from conventional and ecological farms. Part 2: Occurrence of ochratoxin A and fungi in cereals in 1998

Over 200 samples of Polish cereal grain from the 1998 harvest obtained from conventional and ecological farms were investigated for the presence of ochratoxin A and for contamination by microscopic fungi. The frequency of contamination of rye and barley grains from conventional and ecological farms was similar in most cases; it varied from nearly 5 to 12%, respectively, for both types of farming. However, in samples from ecological farms, higher maximum concentrations of ochratoxin A were observed (35 mug kg(-1), overall range 1.4-35.3 mug kg(-1)),for both cereals rye and barley in comparison with rye and barley from conventional farms (maximum levels of 8.8 and 9.7 mug kg(-1), respectively). However, wheat grain from the conventional farms showed ochratoxin A concentrations in a very wide range from 0.6 to 1024 mug kg(-1) and the average frequency of contaminated samples was about 48%. In contrast, in wheat samples from ecological farming, the presence of ochratoxin A ranged from 0.8 to 1.6 mug kg(-1) (mean 1.2 mug kg(-1)) and the frequency of contamination was 23%. From samples containing detectable amounts of ochratoxin A, fungi producing ochratoxin A under laboratory conditions were isolated. They were classified as belonging to the species Penicillium cyclopium, P. viridicatum, Aspergillus ochraceus group, A. glaucus and A. versicolor. Penicillium strains-species known to be producers of ochratoxin A-were isolated from 71% of the samples; in 28% of samples, only Aspergillus strains (species known to be producers of this mycotoxin) were noted.