Fumonisin B-1 and B-2 occurrence in dried fig fruits (Ficus carica L.) under Meander Valley's climatic conditions and relationship with fruit quality

Fusarium is the agent causing endosepsis (internal rot) in fig fruits and it is widespread in fig orchards in the Aegean region. This research was conducted to determine the natural occurrence of fumonisin B-1 (FB1) and B-2 (FB2) on dried fig fruits of Sarilop (syn. Calimyrna) variety which are mainly grown in the Big and Small Meander Basins in the Aegean region, representing 60% of world dried fig production. A total of 262 samples belonging to two quality classes, Class A and Class cull, were collected from 12 different locations during the two crop years in 2004 and 2005. The fumonisin detection method is based on extraction with methanol-acetonitrile-water, derivatization with o-phthaldehyde and quantification by reversed-phase high-performance liquid chromatography with fluorescence detection. The mean concentrations of FB1 and FB2 in fumonisin-positive samples were 0.080 +/- 0.047 mu g g(-1) and 0.055 +/- 0.031 mu g g(-1) and ranged from LOD to 0.332 mu g g(-1) and from LOD to 0.198 mu g g(-1), respectively. The incidence of fumonisins significantly differed between the two crop years. This difference can be attributed to the alteration in the rainfall regime from mid-May to mid-August (7.2 mm in 2004, 90.9 mm in 2005) and number of humid wind currents from a westerly direction (183 in 2004, 492 in 2005) from the end of July and mid-August that may have triggered a higher incidence of Fusarium spp. and thus fumonisin production.