This study evaluates the influence of crop seasons, cultivation regions, and traditional agricultural practices on the occurrence of F. proliferatum and A. flavus in the rice chain in the Mekong Delta, Vietnam. A survey on pre- and post-harvest practices was performed from 2017 to 2019 in parallel with sampling. Results showed that F. proliferatum (36.3%) and A. flavus (10%) were predominantly present throughout the rice chain. These fungi frequently occurred in winter–spring and autumn–winter crops in Can Tho paddy. Especially, F. proliferatum appeared both on the field and during transportation (50–100%), while A. flavus presented at all stages (10–33%). The occurrence of F. proliferatum reduced 70–27% after drying, depended on the seasons, compared to field and transportation stages and could not be detected anymore at further stages. Applying poor pre-harvest agricultural practices such as the use of certain varieties (Jasmine, DT8 varieties), combination of fertilizers (organic–inorganic), fields with crop debris, unhygienic boats, and delayed drying time of 8–12 h or 12–28 h resulted in an increase in fungal contamination on paddy. This study provides a detailed description of fungi contamination in crop seasons, cultivation regions, and agricultural practices, which may help in understanding the fungal dynamic and allow identification of good agricultural practices to mitigate the fungal contamination and potential mycotoxin production.

The current study aimed to evaluate the impact of the crop season, cultivation region, and traditional pre- and post-harvest agricultural practices on mycotoxin contamination in the Mekong Delta rice chain of Vietnam. The results showed that aflatoxins (AFs) and fumonisins (FBs) were predominantly detected in both paddy (n = 91/184, 50%) and white rice (n = 9/46, 20%). Aflatoxin B1 (AFB1)-contaminated paddy samples (n = 3) exceeded the regulatory threshold (5 µg·kg⁻¹). The contamination of paddy with AFs and FBs was not significantly different by growing seasons and cultivation localities. Evidently, in the winter–spring season, fumonisins frequently occurred in paddy planted in Can Tho, while AFs were found in paddy planted in regions Dong Thap and An Giang, and such toxins were absent in Can Tho. Furthermore, the selection of paddy varieties strongly impacted the occurrence of these toxins, especially AFs, for example, line DT8 and Jasmine were susceptible to AFs and FBs. In addition, poor pre- and post-harvest practices (such as crop residue-free fields, fertilizer application, unsanitary means of transport, delayed drying time) had an impact on the AFs and FBs contamination. Our findings can help to understand the dynamics of AFs and FBs in the rice chain in the Vietnamese Mekong Delta, leading to the mitigation of the contamination of AFs and FBs in rice.