Reduction of Yersinia enterocolitica and mesophilic aerobic bacteria in egg-shell by washing with surfactants and their effect on the shell microstructure Original Research Article

The effectiveness of Extran, Tergitol type 08, a sodium hypochlorite solution containing 100 ppm of free chlorine and a combination of Tergitol and sodium hypochlorite (100 ppm of free chlorine in wash solutions for hen eggs contaminated with one potentially pathogenic strain of Yersinia enterocolitica O:9 was assessed. Simultaneously, the effect of these chemicals on the mesophilic aerobic flora and the presence of Yersinia and Salmonella in this flora were investigated. The following order of efficiency was established for the reduction of the Y. enterocolitica populations on eggshell: Tergitol/100 ppm chlorine>Extran=100 ppm chlorine>Tergitol, with reduction of 4·27, 3·11, 3·08 and 2·38 log cycles, respectively. The alterations produced on the eggshell microstructure by the used chemicals were observed by scanning electron microscopy and blue lake penetration. The Tergitol/100 ppm chlorine combination caused the most marked alterations.