Contamination of foods or environments by fungi, especially those resistant to conventional fungicides or drugs, represents a hazard to human health. The objective of this study is to identify safe, natural antifungal agents that can rapidly remove fungal pathogens or contaminants from food and/or environmental sources.Fifteen antifungal compounds (nine benzo derivatives as candidates; six conventional fungicides as references) were investigated. Three benzo analogs, namely, octyl gallate (OG), trans-cinnamaldehyde (CA) and 2-hydroxy-5-methoxybenzaldehyde (2H5M), at 1 g L (3.54 mmol), 1 mL L (7.21 mmol), 1 mL L (5.39 mmol), respectively, achieved ≥ 99.9% fungal death after 0.5, 2.5 or 24 h of treatments, respectively, in in vitro phosphate buffered saline (PBS) bioassay. However, when OG, CA and 2H5M were examined in commercial food matrices, organic apple or grape juices, only CA maintained a similar level of antifungal activity, compared to a PBS bioassay. CA showed higher antifungal activity at pH 3.5, equivalent to that of commercial fruit juices, than at pH 5.6. In soil sample tests, application of 1 mL L (7.21 mmol) CA to conventional maize/tomato soil samples (pH 6.8) for 2.5 h resulted in ≥ 99.9% fungal death, indicating CA could also eliminate fungal contaminants in soil. While the conventional fungicide thiabendazole exerted antifungal activity comparable to CA, thiabendazole enhanced the production of carcinogenic aflatoxins by Aspergillus flavus, an undesirable side-effect.CA could be developed as a potent antifungal agent in food processing or soil sanitation by reducing time/costs necessary for fungal removal. This article is protected by copyright. All rights reserved.