AFLATOXIN VARIABILITY IN PISTACHIOS

Pistachio fruit components, including hulls (mesocarps and epicarps), seed coats (testas), and kernels (seeds), all contribute to variable a flatoxin content in pistachios, Fresh pistachio kernels were individua lly inoculated with Aspergillus flavus and incubated 7 or 10 days. Hul led, shelled kernels were either left intact or wounded prior to inocu lation, Wounded kernels, with or without the seed coat, were readily c olonized by A, flavus and after 10 days of incubation contained 37 tim es more aflatoxin than similarly treated unwounded kernels. The aflato xin levels in the individual wounded pistachios were highly variable, Neither fungal colonization nor aflatoxin was detected in intact kerne ls without seed coats, Intact kernels with seed coats had limited fung al colonization and low aflatoxin concentrations compared,vith their w ounded counterparts, Despite substantial fungal colonization of wounde d hulls, aflatoxin was not detected in hulls, Aflatoxin levels were si gnificantly lower in wounded kernels with hulls than in kernels of hul led pistachios, Both the seed coat and a water-soluble extract of hull s suppressed aflatoxin production by A. flavus.