[Investigation of aflatoxins,mycobiota,and toxigenic fungi during post-harvest handling of Ziziphi Spinosae Semen].

Ziziphi Spinosae Semen is one of the Chinese herbal medicine being susceptible to aflatoxins contamination. To investigate the sources of aflatoxins contamination and toxigenic fungi species on Ziziphi Spinosae Semen,32 samples were collected from multiple steps during the post-harvest processing in this study. Aflatoxins in these samples were determined by immunoaffinity column and HPLC coupled with post-column photochemical derivatization. The dilution-plate method was applied to the fungi isolation. The isolated fungi strains were identified by morphological characterization and molecular approaches. The results showed that aflatoxins were detected in 28 samples from every step during the processing of Ziziphi Spinosae Semen. Three samples were detected with aflatoxin B_1 and 2 samples with both aflatoxin B_1 and total aflatoxin exceeding the limit of Chinese Pharmacopoeia. Especially the samples from the washing step,with the highest detected amounts of AFB_1 and AFs were reached 94. 79,121. 43 μg·kg~(-1),respectively. All 32 samples were contaminated by fungi. The fungal counts on the newly harvested samples were 2. 20 × 10~2 CFU·g~(-1). Moreover,it increased as tphreocessing progresses,and achieved 1. 16×10~6 CFU·g~(-1) after washing. A total of 321 isolates were identified to 17 genera. Aspergillus flavus was the main source of aflatoxins during the processing and storage of Ziziphi Spinosae Semen. One isolate of A. flavus was confirmed producing AFB_1 and AFB_2. The fungal count was significantly increased by composting,and Aspergillus was the predominant genus after shell breaking. The contamination level of aflatoxins was increased by composting and washing.