Increased aflatoxin contamination of dried figs in a drought year

Dried figs (4917 samples) destined for export from Turkey to the European Union were collected between September and December during the very dry crop year of 2007 and tested for aflatoxins B(1), B(2), G(1) and G(2) by immunoaffinity column clean-up and reverse-phase high-performance liquid chromatography (RP-HPLC). While 32% of the samples contained detectable levels of total aflatoxins, 9.8% of them exceeded the European Union limits. Aflatoxin levels were in the range of 0.2-259.46 microg kg(-1) and 2.04-259.46 microg kg(-1) for all samples and samples that exceeded the limits, respectively. A substantial increase in the incidence of aflatoxins was observed in 2007 compared with previous years, most likely due to the drought stress, high temperatures and low relative humidity encountered during the period from January to September of that year. In 2007, the mean temperature was 1-2 degrees C higher, there was 300 mm less total rain, and the mean relative humidity was 10-15% lower than in 2002-06. The average concentration of individual aflatoxins present in the samples was quantified to determine whether the drought conditions promoted certain types of aflatoxins. Among the contaminated samples, aflatoxin B(1) occurred in 97% of the contaminated samples, followed by G(1) in 47%, B(2) in 24%, and G(2) in 6% of samples. Concentrations of individual aflatoxins exhibited great variability among the samples but were not significantly different from those reported in previous studies, which were conducted under conditions without drought and high temperatures.