## 3 Results
### Suppressive Effect of Non-AFB1-Producing A. flavus ATCC 9643 on ATCC 22546 Growth  
Via ATCC 22546-ATCC 9643 co-culturation, a dominance diagram for the two strains' competitive growth was generated, revealing a significant competitive effect on ATCC 22546 growth through ATCC 9643 addition (Figure 2). Figure 1: Aflatoxin biosynthesis gene expression for _Aspergillus flavus_ 22546 (the aflatoxingenic strain) and for _A. flavus_ 96045 and _A. flavus_ 9643 (non-aflatoxigenic strains). _A. flavus_ 96045 was used as a positive control. The experiment was performed in triplicate. Data analysis was conducted using one-way ANOVA, followed by post hoc Tukey’s test. (*, \(p\) < 0.1; **, \(p\) < 0.01; ***, \(p\) < 0.001; ***, \(p\) < 0.0001). Figure 2: In vitro co-cultivation of _Aspergillus flavus_ ATCC 22546, an aflatoxin-producing strain, with two non-aflatoxin-producing _A. flavus_ strains, ATCC 9643 and ATCC 96045, visualized under (**a**) visible light and (**b**) ultraviolet light. _A. flavus_ 96045 was used as a positive control. The two non-aflatoxigenic strains of _A. flavus_ competitively grew in the fungal growth medium containing an aflatoxin strain of _A. flavus_ ATCC 22546. In the ATCC 9643:ATCC 22546 (1:1) inoculation group on the tenth day of incubation (Figure 2), the growth of the non-aflatoxin-producing strain (ATCC 9643, one 5 \(\times\) 5-mm piece of the corresponding fungi grown in solid medium) was apparently equal to that of the aflatoxin-producing strain (ATCC 22546, 1 \(\times\) 10\({}^{6}\) cells). Moreover, the positive control, that is, the non-aflatoxin-producing strain (ATCC 96045, known as AF36, 1 \(\times\) 10\({}^{6}\) cells), exhibited similar growth in the ATCC 96045:ATCC 22546 (1:1) inoculation group until the tenth day of incubation. As shown in Figure 3a, the ATCC 9643 strain inhibited ATCC 22546 growth over six days of incubation, and elevated ATCC 9643 quantities increasingly suppressed ATCC 22546 growth. Conversely, higher ATCC 22546 levels inhibited ATCC 9643 growth. These findings remained consistent after ten days of incubation with the two strains (Figure 3a). In Figure 3b, the fungal growth area showed some similarity when ATCC 9643 and ATCC 22546 were co-cultured, indicating they were competitively grown when they were inoculated simultaneously. Figure 3: In vitro anti-aflatoxin activity using the dominance difference test between a non-aflatoxin-producing strain _Aspergillus flavus_ ATCC 9643 and an aflatoxin-producing strain _A. flavus_ ATCC 22546. (**a**) Colony morphology; (**b**,**c**) colony area (mm\({}^{2}\)). Spore suspensions (n \(\times\) 10\({}^{6}\) spores/mL) were inoculated on a paper disk. The experiment was performed in triplicate. Data analysis was conducted using one-way ANOVA, followed by post hoc Tukey’s test. Lowercase letters denote significant differences among groups: a \(>\) b \(>\) c \(>\) d (\(p<\) 0.05). The competitive growth of ATCC 9643 on rice was validated (Figure 4). Rice exhibited poor _Aspergillus_ strain growth. Therefore, the rice was soaked in water, left on a solid _Aspergillus_ growth medium, or both (Figure 4a-d). Water-submerged rice with or without the fungal growth medium was successfully located for the fungal growth of both strains as ATCC 9643 and ATCC 22546. It was subsequently inoculated with _Aspergillus_ strains, and their competitive growth was observed. After _Aspergillus_ sp. inoculation, the competitive growth between ATCC 9643 and ATCC 22546 was observed until the seventh day (Figure 5a-f). Figure 4: Growth of the strains on the rice medium with and without soaking. (**a,b**) A non-aflatoxin-producing strain _Aspergillus flavus_ ATCC 9643; (**c,d**) an aflatoxin-producing strain _A. flavus_ ATCC 22546. The experiment was performed in triplicate. Data analysis was conducted using one-way ANOVA, followed by post hoc Tukey’s test. Lowercase letters denote significant differences among groups: a > b (\(p<0.05\)). Both _A. flavus_ ATCC 9643 and _A.