Bactericidal Treatment of Hatching Eggs Iv. Hydrogen Peroxide Applied with Vacuum and a Surfactant to Eliminate Salmonella from Hatching Eggs

Bacteria (including salmonellae) can be pulled into and through the shell and membrane of broiler hatching eggs as they cool. When this occurs, salmonellae are out of reach of a surfaceapplied chemical treatment, because direct contact is usually required to achieve a kill. Over many years of research, 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 reduce Salmonella that is artificially inoculated onto hatching eggs. The objective of the present study was to determine whether the efficacy of H2O2 could be enhanced by utilizing vacuum and a surfactant to remove air and reduce surface tension within the eggshell, enabling the bactericide to penetrate deeper into the egg to kill Salmonella. Eggs were inoculated with nalidixic acid-resistant Salmonella typhimurium. Inoculated eggs were treated with H2O2 with or without a surfactant and with or without the application of vacuum to facilitate shell penetration. Thirty percent of eggs exposed to H2O2 with surfactant and vacuum were still positive for the marker Salmonella. Although this represents a decrease in number compared with a water control, 30% remained contaminated. Results demonstrate the difficulty involved in reaching and killing Salmonella that has penetrated the hatching egg, even with an effective bactericide.