A Study on the Spatial Distribution of Zearalenone and Deoxynivalenol in Oat Bran

Zearalenone (ZEN) and Deoxynivalenol (DON) are common Fusarium toxins that are found worldwide in contaminated wheat, corn, oats, and other foods. This study investigated the spatial distribution of ZEN and DON within bagged oat bran and the relationships among fungal taxa. A total of 168 oat bran bags arranged in a three-dimensional space (X = 4, Y = 6, Z = 7) were tested for ZEN and DON concentrations via Enzyme-linked Immunosorbent Assay (ELISA) and fungal communities were analyzed by Internal Transcribed Spacer (ITS) sequencing. Samples were grouped by air-exposed surfaces: G0 (no exposure, n = 48), G1 (one exposed surface, n = 80), G2 (two or three exposed surfaces, n = 40). Results showed strong positive correlations between ZEN and DON spatial distributions (r = 0.691~0.930), with G2 having significantly lower toxin levels than G0 and G1 (p < 0.05). Fusarium spp. (e.g., F. aethiopicum, F. pseudonygamai, and F. fujikuroi) were positively correlated with ZEN and DON (p < 0.05), indicating that they are the primary producers of these mycotoxins. Talaromyces (T. funiculosus and T. stollii) and Sarocladium (S. kiliense and S. strictum) were positively correlated with ZEN, DON, and Fusarium spp., while the yeasts D. hungarica, V. victoriae, and H. sinensis exhibited a negative association with those (p < 0.05). Overall, the distribution of ZEN and DON in bagged oat bran was heterogeneous in three-dimensional space, and the distribution pattern was related to air exposure. The extent of air exposure influenced the composition of the fungal community, and the taxa correlating with Fusarium spp. showed potential synergistic or antagonistic associations, collectively influencing the accumulation of mycotoxins. This study provides a reference basis for the prevention of mold contamination during the stacked bag storage of feedstuffs.