Annual and regional variations of aflatoxin B-1 levels seen in grains and feed coming from Croatian dairy farms over a 5-year period

The aim of the study was to investigate annual and regional differences in the level of aflatoxin B-1 (AFB(1)) in grains and dairy cattle feed. Maize (n = 972), wheat (n = 201), barley (n = 147), oat (n = 136), grain mixtures (n = 168), and dairy cattle feed (n = 325) were sampled from 2009 to 2013 on different farms and in different farm factories situated in four Croatian regions. The samples were analysed for AFB(1) using the validated ELISA immunoassay. AFB(1) was determined in 16.4% of all investigated samples, among which maize was proven to be the most contaminated, with 21.7% of the samples recovered during 2013 harbouring AFB(1) in concentrations over the permissible ones. Levels higher than permitted were observed in 17.9% and 12.3% of grain mixtures and dairy cattle feed,, respectively, whereas concentrations of AFB(1) determined in other crops throughout the investigated period met the stipulated requirements. The results revealed the AFB(1) occurrence to be significantly (p <0.05) dependent on the cultivation region, with the highest levels generally found in maize harvested in 2013 and consequently in grain mixtures and cattle feed that can most likely be associated with climatic conditions as the most critical factor for mould formation, and thus also AFBi production. (C) 2014 Elsevier Ltd. All rights reserved.