Serving Fresno County

CALIFORNIA SAFE RAISIN PRODUCTION DOCUMENTED

Stephen Vasquez has teamed up with USDA-ARS Scientist Jeffery Palumbo to explore if San Joaquin Valley vineyards harbor fungi that produce ochratoxins; a known carcinogen. For the past 5-6 years, Asian and European countries have been testing for the presence of ochratoxins in grape products: fresh grapes, raisins, juice and wine. Commonly found in Mediterranean and South American grape growing regions, Aspergillus species, fungi that produce ochratoxin-A have been identified in California’s vineyards. Vasquez focused on raisins since the industry is changing from tray-dried to dried-on-the-vine (DOV) production. The difference in the two production systems is a cooler, higher humidity environment found in DOV vineyards, which is conducive to fungal growth. Raisins were collected from DOV vineyards prior to processing and sent to Palumbo for fungal morphological and DNA analysis. Results showed that in unprocessed raisins, ochratoxin can be isolated at levels well below the threshold set by raisin importing countries. It is expected that raisins processed by California raisin packers would further decrease the amount of detectable ochratoxin.  Raisin grape growers are confident that their product is safe and meets the ochratoxin test levels set by Asian and EU counties.

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