Analysis on the Growth of Aspergillus ochraceus and Ochratoxin A Accumulation on Raisin Surfaces at Various Temperatures and Humidity Conditions

Ochratoxin A(OTA)is a mycotoxin produced by Aspergillus and Penicillium species. This mycotoxin is a common contaminant of various foods including cereal products and dried fruits. This research studied the growth of Aspergillus ochraceus and OTA concentration on inoculated raisins at various temperature and humidity environment. The optimum growth of Aspergillus ochraceus was observed at 20 ℃ and moisture level 18 %-22 %, which does not match the condition of maximum accumulation of OTA observed at 25 ℃ and moisture level 22 %-26%. Data indicates that low temperature(2℃-10℃)will delay but not hider OTA formation, while low moisture content (14 %)hider the formation of OTA. The study also evaluated the reduction of Aspergillus ochraceus population and OTA concentration using water rinsing, sonication, and UV radiation treatments. Among the three, sonication provided best reduction on both Aspergillus ochraceus population (2.7 log CFU/g)and OTA concentration(41.4 %).