Bactericidal treatment of hatching eggs IV. Hydrogen peroxide applied withvacuum and a surfactant to eliminate Salmonella from hatching eggs

Bacteria (including salmonellae) can be Dulled into and through the shell a nd membrane of broiler hatching eggs as they cool. When this occurs, salmon ellae are out of reach of a surface-applied chemical treatment, because dir ect contact Is usually required to achieve a kill. Over many years of resea rch, a large number of disinfectant chemicals have been tested on hatching eggs. We have found H2O2 (1.4%) to be a fairly effective disinfectant to re duce Salmonella that is artificially inoculated onto hatching eggs. The obj ective of the present study was to determine whether the efficacy of H2O2 c ould be enhanced by utilizing vacuum and a surfactant to remove air and red uce surface tension within the eggshell, enabling the bactericide to penetr ate deeper into the egg to kill Salmonella. Eggs were inoculated with nalid ixic acid-resistant Salmonella typhimurium . Inoculated eggs were treated w ith H2O2 with Or without a surfactant and with or without the application o f vacuum to facilitate shell penetration. Thirty percent of eggs exposed to H2O2 with surfactant and vacuum were still positive for the marker Salmone lla. Although this represents a decrease in number compared with a water co ntrol, 30% remained contaminated. Results demonstrate the difficulty involv ed in reaching and killing Salmonella that has penetrated the hatching egg, even with an effective bactericide.