## 3 Results and Discussion
### Use of SLD as an Antifungal Agent on Corn Kernels: Raised Bed Analysis (Large Scale)
expansum_ FR2 exhibited higher sensitivity to 4I3M, as determined by the smaller colony size formed (viz., fungal growth: 58 \(\pm\) 0% W1 vs. 22 \(\pm\) 5% FR2 compared to the control). Therefore, results indicated that 4I3M is a redox-active compound, where the level of redox-activity (redox cycling) exerted by 4I3M was enough to induce the higher susceptibility of FR2 to 4I3M toxicity when compared to the parental strain W1. Altogether, we speculated that 4I3M could also be applicable as a potent antifungal and/or anti-aflatoxigenic agent in foods/crops without affecting seed germination. There was a differential antifungal efficacy between 4I3M (non-fumigant) and SLD (fumigant), which might be due to the differences in the level of redox activity of the compounds. The order of antifungal efficacy was: SLD (complete inhibition of fungal growth) > 4I3M (complete inhibition of AF production) (high to low). In summary, via the risk assessment testing using thirteen NP or their structural derivatives, we determined that several benzaldehyde/THY derivatives could enhance AF production if applied at sub-inhibitory concentrations in _A. flavus_ and _A. parasiticus_. The results indicated that caution should be exercised in the use of NP/derivatives so as not to  
Figure 5: Antifungal and anti-aflatoxigenic activity of 4I3M: (**a**) antifungal activity of 4I3M; (**b**) inhibition of AF production by 4I3M. interfere with the safe production of foods/crops as well as public food safety. Therefore, the precise determination of optimum concentrations of NP/derivatives for usage is necessary to prevent abnormal enhancement of mycotoxins during industrial application. Conversely, SLD and 4I3M appear to be an effective antifungal and/or anti-mycotoxicing agents, where SLD prevented the growth of AF-producing _A. flavus_ as a fumigant while 4I3M effectively disrupted AF production by _A. flavus_ and _A. parasitism_. The use of SLD as a fumigant could also warrant the minimal deposition of the compound on the surface of crops during application. Collectively, NPs or their structural derivatives, such as SLD or 4I3M, can be a potent source of antifungal or anti-mycotoxicing agents, which can lower conventional pesticide burden as well as overcome fungicide resistance of fungal pathogens during food/crop production. The determination of the mechanism of antifungal and/or anti-mycotoxicing activity of NP including SLD or 4I3M requires future in-depth investigation. In conclusion, if technological advancements are further explored or achieved, the outcomes of this study will result in effective fungal and mycotoxin control, thus ensuring the safe production of foods/crops and new revenues for the food/crop industry. While not pursued in this study, in-depth determination of the \"antifungal\" efficacy of other NP/derivatives (in addition to SLD and 4I3M) can provide further insight as to the utility of various benzaldehydes, cinnamic acids or isopropyl methylphenol derivatives for safe food/crop production. The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app142110000/s1](https://www.mdpi.com/article/10.3390/app142110000/s1)]([https://www.mdpi.com/article/10.3390/app142110000/s1](https://www.mdpi.com/article/10.3390/app142110000/s1)), Figure S1: Petri plate assay on segmented dishes; Figure S2: The level of fungal growth with the treatment of thirteen NP/derivatives at sub-lethal concentrations; Figure S3: Antifungal activity of salicaldehyde tested against _A. flavus_ and seedborne contaminants on corn seeds; Figure S4: Antifungal activity of salicaldehyde tested against seedborne contaminants on pistachios. **Author Contributions:** Conceptualization, J.H.K. ; methodology, J.H.K. ; validation, J.H.K., K.L.C., D.F. and S.B.L.S. ; formal analysis, J.H.K., K.L.C., D.F. and S.B.L.S. ; investigation, J.H.K. and W.M.H.-C.; resources, J.D.P., W.M.H.-C. and K.O. ; data curation, K.L.C. and D.F. ; writing--original draft preparation, J.H.K.