Basil, marjoram, nutmeg and oregano essential oils as natural preservatives of Quark-type cheese

This study aims to evaluate the in vitro antimicrobial activity of basil, marjoram, nutmeg, and oregano essential oils to use the essential oil with better results for Quark-type cheese preservation. To verify the shelf life of Quark-type cheese without essential oil (CTL) and Quark-type cheese added with 0.05% essential oil (OE), microbiological and physicochemical analyses were performed for 35 days (4 °C). The acceptability of the product was also evaluated. The oregano essential oil showed strong antimicrobial activity in the disk-diffusion test (34.0 to 51.0 mm), and lower values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against all species of bacteria tested. A lower mold and yeast count (p < 0.05) was observed during storage in OE denoting a positive effect in delaying its deterioration. On the other hand, there was no difference (p > 0.05) between the CTL and OE count of total mesophiles and Enterobacteriaceae. For the physicochemical parameters evaluated, there were no significant differences between the CTL and OE, thus denoting that the typical characteristics of this cheese were maintained. The Quark-type cheese added with oregano essential oil also showed good acceptability (> 7), which is a way to preserve the product with a natural additive.