Several compounds (cinnamon oil, cinnamaldehyde, clove oil, eugenol, and potassium sorbate) were assayed to evaluate their potential as inhibitors of Penicillium expansum growth on apples and in apple juice. The effectiveness of inhibitor was dependent on the apple cultivar treated. Both 0.1% cinnamon oil and 0.5% potassium sorbate decreased spoilage as measured by lesion diameter in most of the cultivars studied. Patulin was not detected in apple juice containing 0.3% cinnamon oil or 0.5% sorbate after incubation with P. expansum for 7 d at 25°C. The addition of benomyl (0.5–5 ppm) increased patulin production by P. expansum grown in apple juice. These results indicate that surface application of cinnamon oil or potassium sorbate might be an effective postharvest treatment for apples, and addition of these compounds to apple juice products that do not receive additional heat treatment, such as ‘fresh’ apple cider, would prevent patulin production by P. expansum.
Contribution from the Missouri Agricultural Experiment Station. Journal Series 1, paper number 11,819.