Analysis of fungal diversity in processed jujube products and the production of mycotoxins by typical toxigenic Aspergillus spp.

Processed jujube products are susceptible to contamination by fungi such as <i>Aspergillus</i> spp., which produces mycotoxins that could lead to health problems in consumers. In this study, 58 samples of processed jujube products (including 5 types such as dried jujubes) were collected from different markets in Shihezi (Xinjiang, China). The fungal diversity and the fungi isolated from processed jujube products were systematically analyzed through high-throughput sequencing and molecular biological identification (based on the ITS and/or <i>BenA</i> and <i>CaM</i> regions). In total, the 105 strains of fungi were isolated and identified as belonging to the dominant genera were <i>Aspergillus</i>, <i>Cladosporium</i>, <i>Alternaria</i>, and <i>Penicillium</i>. High-throughput sequencing indicated that <i>Alternaria</i>, <i>Didymella</i>, <i>Cladosporium</i>, and <i>Aspergillus</i> were the dominant fungi in processed jujube products. ELISA showed that <i>A. flavus</i> produced about 19.3862-21.7583 μg/L, 6.5309-11.0411 μg/L, 0-15.4407 μg/L, 0-5.6354 μg/L, and 0-6.0545 μg/L of AFT, AFB₁, AFB₂, AFM₁, and AFM₂, respectively. In addition, concentrations of OTA produced by <i>A. niger, A. tubingensis,</i> and <i>A. ochraceus</i> were found to range from 5.2019 to 18.5207 μg/L. Therefore, the separation of <i>Aspergillus</i> with good mycotoxin-producing abilities from processed jujube products poses a latent threat to consumer health.