Effect of shell egg pasteurization on its refrigerated storage quality

The effect of thermal pasteurization on the refrigerated storage stability of chicken shell eggs was investigated. Fresh sound chicken eggs were cleaned using detergent-sanitizer solution and then pasteurized in a circulating water bath (57°C; 15 min). Both pasteurized and unpasteurized (control) eggs were held under refrigeration (5±1°C; 80–85% RH) for 60 days and analyzed for their physico-chemical, functional, microbiological and sensory quality at fortnightly intervals. Results showed no adverse effect of thermal treatment on the albumen protein solubility and Haugh unit with added advantage of a drastic reduction in microbial (mesophiles, psychrotrophs, coliforms, staphylococci, yeast and moulds) counts on both egg shell surface and in egg contents following pasteurization. Storage study also revealed no significant differences in percent egg weight loss, pH, albumen viscosity, albumen protein solubility, volume and stability of albumen foam and thiobarbituric acid value of yolk between thermally treated and control groups. Pasteurization did not alter the electrophoretic pattern of albumen proteins. Apart from initial reduction, pasteurization of eggs retarded the multiplication of these microflora during storage. Although pasteurized and unpasteurized eggs remained fairly acceptable sensorily even on 60^th day of storage, the pooled treatment means for appearance and overall acceptability scores of the former eggs were significantly (P<0.05) higher than those of the latter group. These findings indicated that the pasteurization process employed for table eggs appeared beneficial in improving their microbial quality without adverse effect on their storage stability and albumen functional property.