Effect of UV-C light in the preservation of raw fermented beverages

The aim of this work was to check the efficacy of an annular ultraviolet reactor for stabilizing the growth of lactic acid bacteria (LAB), the main components of the microbiota of three raw fermented beverages, Boza, Ayran and Matsoni during cold storage. The ultraviolet (UV) dose of 260 mJ cm-2 caused a reduction of 2.6 and 1 log CFU mL-1 in the LAB loads of Boza and Ayran samples, respectively, whereas multiple UV treatments were required for Matsoni; they caused the decrease of 3 log CFU mL-1 in LAB counts. Twenty-two bacterial strains, belonging to 11 species, were identified in the natural microflora of the three beverages before and after the UV treatments. Only a minimal post-acidification process was registered up to day 30 in all the three beverages. This ultraviolet device is at disposal of beverage manufacturers, who could apply it for producing microbially-stable drinks with an extended shelf-life.