Application of reuterin-containing edible coating to inhibit the growth of aflatoxigenic Aspergillus flavus on nutmeg

Contamination of Aspergillus flavus (A. flavus) and aflatoxin in nutmeg remains problematic due to the poor postharvest handling practices and the climate, which is favorable for fungal growth in Indonesia. Using the natural antifungal agents can be an alternative measure to control the aflatoxin-producing fungal growth. This current study aimed to evaluate the efficacy of reuterin in inhibiting aflatoxigenic A. flavus growth on the nutmeg during storage. Reuterin at concentrations of 4, 6, 8, and 10 × MIC (1 MIC = 6 mM) was incorporated into a carboxymethyl cellulose (CMC)-based edible coating to coat the surface of nutmeg spiked with A. flavus conidia (2.5 × 10² CFU/g). Results showed that reuterin effectively extended the lag phase of A. flavus growth on the coated nutmeg and disrupted the hyphal development and conidiation. At a minimum concentration of 48 mM (equal to 3.63 mg/mL coating solution or 630 mg/kg nutmeg), reuterin inhibited completely the growth of A. flavus on the nutmeg stored at an RH of 97% and a temperature of 30 °C for 30 days. This study confirmed that the application of reuterin incorporated into a CMC-based edible coating was an effective measure for inhibiting aflatoxigenic A. flavus growth on the nutmeg during storage.