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United States Department of Agriculture

Agricultural Research Service

Title: Comparison of Two Populations of Aspergillus Flavus and Aspergillus Parasiticus Isolated Five Years Apart in a California Orchard

item Hua, Sui Sheng
item Sarreal, Siov
item Singh, Harpreet - WRRC, STUDENT VOLUNTEER
item Edirippulige, Prasadi - WRRC, STUDENT VOLUNTEER

Submitted to: Aflatoxin Workshop
Publication Type: Abstract Only
Publication Acceptance Date: October 25, 2004
Publication Date: N/A

Technical Abstract: Both Aspergillus flavus Link and A. parasiticus Speare cause aflatoxin contamination in crops such as corn, cottonseed, peanuts and tree-nuts. These two fungal species are saprophytes which infect plants through woundings. A. flavus is typically the dominant aflatoxigenic species. A. flavus produces aflatoxin B1 and B2. Many isolates of A. flvus do not produce aflatoxin and are named atoxigenic strains. A. parasiticus strains produce aflatoxins B1, B2, G1 and G2 and atoxigenic isolates has rarely been described. Of the four aflatoxins, B1 is the most potent carcinogen known. Fungal cultures collected in a California orchard in spring 1998, spring 2003 and summer 2003 were analyzed for aflatoxins production, morphoty and pectinase activities. The data indicate that there is an increase in afltoxigenic population from 1998 to 2003. The percent of toxigencic isolates of both A. flavus and A. parasiticus is 33% and 66% in spring of 1998 and 2003 respectively. The isolates from wounded pistachio nut-fruits in the summer of 2003 consist 55% of A. flavus and 45% of A. parasiticus. The percent of isolates producing AFB1 is reaching 88% in wounded pistachio nut-fruits collected in the summer of 2003.

Last Modified: 4/22/2015
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