Impact of UV-C treatment on the inactivation of microbes and amino acid composition in cow milk and buffalo milk: A comparative study

The study investigates the effect of UV-C light on microorganism's inactivation, amino acid (AA) profile, functional groups of milk metabolites and physiochemical properties of cow and buffalo milk. Cow and buffalo milk were inoculated with Escherichia coli, Salmonella enterica, and Listeria monocytogenes. Inoculated milk samples were treated with UV-C doses of 0, 1.5, 3.1 and 4.6 J/cm2. At 4.6 J/cm2 E. coli, S. enterica and L. monocytogenes were inactivated by 4.07. 4.41, and 4.92 log10 in cow milk, and 3.71, 3.74, and 4.42 log10 in buffalo milk, respectively. The physicochemical properties showed no significant changes except colour with significant changes (P<0.05). The AA profile remains unchanged, 1H NMR and FTIR results revealed no difference in milk metabolites and functional groups after UV treatment. The sensory evaluation data showed, that no major differences were detected between control and UV-C treated milk.