A field survey of pistachio (Pistacia vera) nut production and storage in turkey with particular reference to aflatoxin contamination

A field study of soils and pistachio nuts in three major pistachio‐growing areas of Turkey has been undertaken. The predominant soil fungus isolated from all three areas was Aspergillus niger; isolates of Fusarium, Trichoderma, Mucor and Rhizopus species were also common. A flavus and A. ochraceus and related organisms were isolated only from the plateau of Gaziantep. The dominant external mycoflora of the immature nuts from all sites consisted of A. niger, A. flavus and Penicillium spp. There was no evidence for fungal contamination of immature endosperms nor of freshly dehulled nuts, but stored dehulled nuts and dust samples taken from ware‐houses were extensively contaminated with A. flavus, A. niger and A. ochraceus. Of 43 A. flavus isolates tested, 20 produced aflatoxins on laboratory media or on rice; all 11 isolates of A. ochraceus tested produced ochratoxin A on laboratory media. The results obtained are discussed in relation to agricultural and marketing practices for Turkish pistachio nuts.