The waxberry, Myrica rubra (Lour.) S. et Zucc., a fruit native to Southern China, is well known for its sweet-and-sour flavor (Cheng et al., 2015) and high antioxidant capacity, which is thought to provide health benefits due to the contents of phenolics, anthocyanins, and vitamin C (Huang et al., 2014; Yang et al., 2009). However, since postharvest quality rapidly decreases in about 1–2 d at room temperature (Zhang et al., 2005), waxberries are generally only marketed near the point of origin. Furthermore, without peel protection and susceptible to mechanical injury, waxberries are prone to fungal contamination by Alternaria spp., Penicillium spp., and Aspergillus spp., resulting in severe postharvest losses (Ma et al., 2016).

Chemical sanitizers that have been registered on waxberries are allowed to use to control fungal disease before harvest, such as acetamiprid and pyraclostrobine (Yang et al., 2017). The maximum residue levels established in China are 2 mg/kg and 3 mg/kg, respectively. However, residues of synthetic sanitizers generally contain chlorine, which slowly disintegrates and therefore is an environmental pollutant that poses carcinogenic and teratogenic risks to humans. Hence, the use of synthetic sanitizers is forbidden in many areas. In addition, the application of several pesticides is strictly regulated at 15 d before the ripening season. Moreover, customers are now more conscious of these issues, which has promoted the use of broad-spectrum fungicides that are not only effective, but also environmentally friendly and biodegradable.

Various plant-derived essential oils (EOs) contain bioactive constituents with broad-spectrum antibacterial and antifungal activities that are both environmentally safe and biodegradable (Ju et al., 2019). The antibacterial and antifungal activities of EOs are exerted through various mechanisms, including infiltration of the cytoplasmic membrane, disruption of cellular structures, inhibition of drug-resistance enzymes, and attacking synthesis of adenosine triphosphate (Hyldgaard et al., 2012). The EOs of various spices have significant impact on the viability of fungal cells, mycelium development, and mycotoxin production (Mahgoub et al., 2019). Therefore, EOs can be applied to prevent spoilage and increase the shelf life of fruit and vegetables, while successfully meeting the criteria for environmentally friendly antimicrobial agents (Bhaskara Reddy et al., 1998; Mekawi et al., 2019).

The mountain pepper (Litsea cubeba), a specific commercial woody oil plant, is native to Australia, Southern China, North America, and Southeast Asia (Li et al., 2022). The EO of L. cubeba (LCEO) is widely utilized in chemical and pharmaceutical industries, as well as a spice additive in tobacco, food, and cosmetic products (Li et al., 2014). Several studies have showed the antimicrobial activities of LCEO against a number of pathogenic bacteria and spoilage microorganisms. Li et al. (2016) revealed that LCEO efficiently inhibited the mycelial growth and aflatoxin B1 secretion. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of LCEO against Aspergillus flavus were 0.5 μL/mL and 1.0 μL/mL, respectively. Liu and Yang (2012) revealed that the minimal microbicidal concentrations of LCEO against Hansenula anomala, Listeria monocytogenes, and Lactobacillus plantarum were 0.375, 0.750, and 1.50 mg/g, respectively. However, relatively a few studies have investigated the antifungal mechanisms of LCEO to reduce spoilage of waxberries.

Therefore, this study aimd to elucidate the mechanism employed by LCEO to inhibit the proliferation of Penicillium oxalicum as a novel antifungal agent to increase the shelf life of waxberries.