Effects of UV-C on physicochemical quality attributes and Salmonella enteritidis inactivation in liquid egg products

Abstract

The perspectives of UV-C radiation as a non-thermal treatment for liquid egg products were evaluated from the point of view of the effects on egg quality attributes and the decontamination efficiency against the main egg contaminant Salmonella enterica subsp. enterica Ser. Enteritidis. UV-C treated egg fractions (egg yolk, egg white and whole egg) were analyzed for changes in pH, color, temperature-dependent viscosity and TBARS index, and were inoculated with S. enteritidis (ATCC 13076). Contrary to heat treatments, UV-C was not affecting viscosity and pH. Browning due to Maillard was perceptible in egg yolk and whole egg at low UV-C doses, but the corresponding browning indexes were always lower than in heat pasteurized egg fractions. Major changes were only due to lipid oxidation. TBARS values at the highest UV-C doses were larger than in pasteurized egg yolk and whole egg; under dynamic conditions and 0.61 J cm−2, results were not significantly different to natural untreated samples. And UV-C was effective to inactivate S. enteritidis. In egg white, a load reduction up to 5.3 log10 was achieved under dynamic conditions (9.22 J cm−2, 39 min), while 3.3 log10 and 3.8 log10 reductions were recorded in egg yolk and whole egg. Static treatments were less efficient, but still, load reductions between 1.7 and 2.8 log10 were obtained. At 3.94 mW cm−2, time necessary to achieve a 4D reduction of Salmonella cells was estimated to be around 7.4 min in egg white.