Comparison of homogenization techniques and incidence of aflatoxin contamination in dried figs for export

Abstract

To determine differences in mean aflatoxin contamination and subsample variance from dry and slurry homogenizations, 10 kg of six different, naturally contaminated dried fig samples were collected from various exporting companies in accordance with the EU Commission Directive. The samples were first dry-mixed for 5 min using a blender and sub-sampled seven times; the remainder was slurry homogenized (1 : 1, v/v) and sub-sampled seven times. Aflatoxin B1 and total aflatoxin levels were recorded and coefficient of variations (CV) computed for all sub-samples. Only a small reduction in sub-sample variations, indicated by the lower CV values, and slight differences in mean aflatoxin B1 and total aflatoxin levels were observed when slurry homogenization was applied. Therefore, 7326 dried figs, destined for export from Turkey to the EU and collected during the 2008 crop year, were dry-homogenized and tested for aflatoxins (B1, B2, G1 and G2) by immunoaffinity column clean-up using RP-HPLC. While 34% of the samples contained detectable levels of total aflatoxins (0.20-208.75 µg kg(-1)), only 9% of them exceeded the EU limit of 4 µg kg(-1) in the range 2.0-208.75 µg kg(-1), respectively. A substantial increase in the incidence of aflatoxins was observed in 2008, most likely due to the drought stress experienced in Aydin province as occurred in 2007.

Developments in mycotoxin analysis: an update for 2009-2010

“…Although the method gave low limit of detections (LODs) and good repeatabilities, extraction recoveries ranged from 49% to 59%. A comparison between slurry and dry blended homogenisation for aflatoxins in dried figs demonstrated little difference between the two techniques and the latter was used for an extensive surveillance of export products (Bircan, 2009a). Aflatoxins and OTA in high-sugar-content traditional Turkish delicacies, such as baklava and halvah, were determined by grinding the sample under liquid nitrogen prior to conventional extraction and clean-up on immunoaffinity columns (IACs) (Senyuva et al, 2009).…”