Control of Penicillium sp. on the Surface of Italian Salami Using Essential Oils

The goal of this study is to evaluate the in vitro effects of rosemary, salvia, oregano and clove oils at volume fractions of 1000, 750, 500, 250, 100, 50, 26, 10 and 5 µL/mL (100, 75, 50, 25, 10, 5, 3, 1 and 0.5%) on the growth of contaminating fungi in salami. The in vitro effect of the oils against fungal growth was indicated by zones of inhibition. Rosemary oil showed an inhibition zone of 9.6 mm only at the maximal volume fraction (1000 µL/mL). Salvia oil showed inhibition zones of 12.2, 11.2 and 10.5 mm only at the three highest fractions tested. Based on the inhibition zones, clove oil at 125 and 250 µL/mL, oregano oil at 250 and 500 µL/mL and a mixture (1:1 by volume) of the two oils at 100 µL/mL were selected to be applied to the surface of salamis. A significant reduction of fungal growth in all of the oil-treated samples was confirmed by visual inspection. A sensory analysis revealed that the samples treated with 125 µL/mL of clove oil or 100 µL/mL of a mixture of oregano and clove oil showed no significant flavour differences compared with the control. Carvacrol and eugenol were the principal compounds in oregano and clove oils, respectively, and were most likely responsible for the antifungal activity.