The Analysis of a Feed Component Imported into South Africa for Aflatoxin in Relation to Fungal and Mycotoxin Contamination

Abstract

Currently there is concern with respect to the occurrence of mycotoxins in feed commodities, which could result in the loss of animal production and danger to consumers. Recent legislation to control the trading of such contaminated materials has been initiated with the result that it is imperative to be able to analyse for mycotoxins in feed commodities, rapidly and with sufficient accuracy to ensure that bulk cargoes of such materials are within set safety limits.

To this end a large batch (800 tonnes) of cotton-seed meal was consigned to a South African feed miller and was sampled according to a protocol devised under the European Union Framework 6 Biotracer programme. These were split and analysed for aflatoxins (AFs) by two laboratories using the VICAM fluorimetry aflatoxin method (VF) and by an high performance liquid chromatography (HPLC) method (HPLC) as part of another study to determine the statistical variation of using composite samples derived from a large bulk cargo (Reiter et al., 2011) .

The results from the HPLC method showed that all the composites were contaminated with aflatoxins (AF) ranging from 24 - 93μg/kg. A comparison of the two analytical methods used, showed that the results compared in terms of trend but in general the Vicam fluorimetry method (VF) gave a higher concentration of aflatoxin B1 (AFB1) ranging between 26 - 164μg/kg.

The levels of AF found were in several cases higher than those permitted by current legislation and would not have been allowed into the European Union. The methodology used allowed for reduced sampling and a more rapid method of analysis to assess AF contamination in commodities, subject to further development.

The predominant fungi isolated and identified were Aspergillus flavus and parasiticus, which are main producer of AFs in the environment.