Thyme is a well known plant used as culinary and medicinal ingredient due to its powerful essential oil. The objective of this study is to evaluate the effect of bulk Thyme essential oil and its nanoemulsion on the quality of contaminated milk. Quality of milk was assessed based on different fermentation indicators: total protein content, milk acidity and total viable count, as well as on its oxidative stability and antioxidant activity. Results exhibited that adding free or nano-encapsulated essential oil was very efficient in inhibiting bacterial growth. The sensory evaluation revealed that essential oil nanoencapsulation had ameliorated panelist appreciation to treated milk. The analysis should help shed some light on new food conservation methods, and should be especially useful to food researchers, professionals in Food Industry, especially Diary Industries.