Occurrence of ochratoxin- and citrinin-producing fungi on developing Danish barley grain

The distribution of Aspergillus and Penicillium spp. isolates that produce ochratoxin A (AO) and citrinin was studied on developing barley from diverse locations in Denmark during the 1977 crop year. From 33 test fields, 243 isolates of the two genera were obtained with significant numbers of isolates on the grain at the earliest sampling date (1-2 weeks postanthesis). No specific argronomic factor was linked to the distribution of Aspergillus and Penicillium spp. A taxonomic study of 108 representative isolates of the two genera showed that A. flavus, P. chrysogenum, and P. purpurrescens were the predominant species. An investigation of the toxin-production capability of the identified species showed that seven strains (6.5%) produced OA and a single isolate synthesized citrinin. P. purpurrescens was the dominant OA-producing species with four toxin-positive isolates.