Effect of processing on ochratoxin A content in dried beans.

Dried pink beans naturally contaminated with ochratoxin A (OTA) and dried carioca beans artificially contaminated with OTA by inoculation with Aspergillus ochraceus (ATCC 22947) were tested for ochratoxin A levels as follows: dried beans were washed with water for 2, 60 or 120 min, soaked in water for 60, 120 min or 10 h, and cooked for 60 or 120 min. At each step, test water and beans were separated. Test water, raw beans and cooked beans were analyzed for OTA. The amount of OTA partitioned into water and in residual beans was determined by methanol-sodium bicarbonate extraction, buffer dilution, immunoaffinity column cleanup, liquid chromatographic separation and fluorescence detection. The results demonstrated that the distribution of OTA in processing water and beans depends on the method of preparation. All treatments (washing, soaking and cooking) when applied individually reduced the amounts of OTA retained in bean flour and whole beans. Higher amounts of OTA remained in whole beans than in bean flour after removing the processing water. The combination of the three treatments eliminated about 50% of the toxin from whole beans. This study provides evidence that discarding the washing, soaking and cooking water leads to a significant reduction in OTA contamination in dried beans.

Occurrence of aflatoxins and fumonisins in Incaparina from Guatemala.

The occurrence of aflatoxins and fumonisins in Incaparina was investigated. Incaparina is a mixture of corn and cottonseed flour with added vitamins, minerals and a preservative. It has been marketed as a high-protein food supplement, particularly for children on protein-deficient diets. According to estimates, 80% of Guatemalan children in their first year are given Incaparina to provide an adequate diet. Eight samples of Incaparina manufactured in Guatemala were collected. Five were from three different geographical locations in the USA and three were from Guatemala. Seven were examined for fungal contamination and analysed for aflatoxins and fumonisins. Aspergillus flavus was the predominant fungus in all samples purchased in the USA and in one sample purchased from Guatemala, whereas Fusarium verticillioides was present in only two samples (one from the USA and one from Guatemala). All samples contained aflatoxins, ranging from 3 to 214 ng g(-1) and <2 to 32ng g(-1) for aflatoxin B(1) and aflatoxin B(2), respectively; and one sample contained aflatoxin G(1) (7 ng g(-1)). Total aflatoxins present ranged from 3 to 244 ng g(1). All samples contained fumonisins, ranging from 0.2 to 1.7 microg g(-1), <0.1 to 0.6 microg g(-1), and <0.1 to 0.2 microg g(-1) for fumonisins B(1), fumonisin B(2), and fumonisin B(2), respectively. Total fumonisins present ranged from 0.2 to 2.2 microg g(-1). The identity of aflatoxin B(2) was confirmed using both the chemical derivatization method and liquid chromatographic (LC)/mass spectrometric (MS) analysis. Appropriate regulatory action was recommended for the import of Incaparina and has been in effect since 22 December 1998.