The antifungal activity of cinnamon (Cinnamomum cassia Presl), litsea [Litsea cubeba (Lour.) Pers.], clove (Syzygium aromaticum L.), thyme (Thymus mongolicus Ronn.) and citronella (Cymbopogon winterianus Jowitt) essential oils (EOs) against the dominant fungi isolated from moldy peanuts was investigated in this research. Firstly, strain YQM was isolated and identified by morphological characterization and 18S rRNA gene sequence analysis to be Aspergillus flavus (A. flavus). Next, antifungal effects of single or mixed EOs on strain YQM were evaluated by the inhibition zone test. The cinnamon-litsea combined essential oil (CLCEO, V_{cinnamon oil}:V_{litsea oil} = 3:5) displayed the best antifungal effect on strain YQM. The chemical composition of CLCEO was identified and quantified by gas chromatograph-mass spectrometry (GC-MS), and results revealed that the major components of CLCEO were cinnamaldehyde and citral. Finally, the effect of EOs on the microstructure of strain YQM mycelia was observed under scanning electron microscope (SEM). The mycelia exposed to cinnamon essential oil (CEO) and litsea essential oil (LEO) were partly deformed and collapsed, while the mycelia treated with CLCEO were seriously damaged and the deformation phenomena such as shrinking, shriveling and sinking occurred. Therefore, CLCEO has great potential for using as anti-mildew agents during peanut storage.

Grain is highly vulnerable to contamination by fungi during storage, leading to reduced product quality and substantial economic losses. Lactic acid bacteria (LAB) have the potential to be used as antifungal agents; however, strains aimed at inhibiting stored grain molds remain limited, and the inhibitory mechanisms require further investigation. To solve this problem, 71 LAB strains were isolated from various samples. Among these, 17 strains exhibiting inhibitory activity against A. flavus, A. niger and P. citrinum were selected using a dual-layer plate assay. Based on morphological characterization and 16S rRNA gene sequence analysis, these strains were classified as Weissella cibaria, Pediococcus pentosaceus, and Lactiplantibacillus paraplantarum. Further investigations involving pH adjustment, catalase, and proteinase K treatments confirmed that organic acids were the primary antifungal substances in LAB cell-free supernatant (CFS). HPLC quantification identified acetic acid, malic acid, lactic acid, phenyllactic acid and citric acid contained in the CFS. Antifungal assays verified that acetic acid and lactic acid exhibited the strongest inhibitory effects against P. citrinum and A. flavus, whereas phenyllactic acid and acetic acid demonstrated the most potent suppression against A. niger. These findings established a theoretical basis for the application of LAB CFS in grain storage.