Recognition and Determination of Contaminated Pistachios to Aflatoxin in Processing Stage

Abstract

Pistachio is one of the most important horticultural products of Iran with special economic importance. In average 70% of Iran pistachio are exported. Aflatoxin is secondary metabolites of fungus such as Aspergillus flavus and A. parasiticus. If favorite condition is prepared for stabilization of fungi spores producing Aflatoxin, the first pistachio contamination to Aflatoxin occurs in orchard. The most important way for penetration of mentioned fungus is cracking in pistachio hull in orchard. The most dangerous kind of cracking is splitting. The shells of most pistachio nuts split naturally in the orchard prior to harvest. Sometimes the hull is attached to the shell so that it splits with the shell, exposing the kernel to moulds and insects. This is called an early split. Although the importance of splitting for mould, aflatoxin and insect contamination is well established, very little is known concerning the physical property of split pistachio. In order to determination appearance and physical properties of contaminated pistachios this researched was carried out on three commercial Iranian pistachio cultivars of Owhadi, Kallehghochi and Ahmadaghaii in processing stage in two mechanized pistachio processing and two sampling times. Sampling were done from non-stain and stained split pistachio on the surface of water, stained and non-stained of pistachio under the water (sank pistachio), small pistachio, deformed pistachios, shelled pistachio and intact pistachio from the end of processing. Stained pistachios were divided in 3 groups including group 1 (amount of stain 1-30%), group 2 (amount of stain 31-60%) and group 3 (amount of stain more 60%). The amount of aflatoxin was measured by scanner-TLC in each sample. The results indicated that stained pistachio on the surface of water had the highest amount of aflatoxin. With increasing of stain level on shell, the amount of aflatoxin increased remarkably. The amount of aflatoxin in stained sinked pistachios of groups 1, 2, 3, was 490, 1364.7 and 1782 ppb respectively. Small, deformed and shelled pistachios had negligible amount of aflatoxin and final pistachios (intact pistachio from the end processing) showed any contamination to aflatoxin.