When developing the final rule to prevent contamination of shell eggs with Salmonella Enteritidis, FDA recognized that cleaning and disinfection of poultry houses as well as refrigeration of eggs were two ways to control growth of SE, if it is present, in the farm environment and the egg itself.
While poultry houses are kept quite clean, feathers, dust and feed can fall to the floor of the houses. Cleaning and disinfection of the houses reduces the level of bacteria in the environment and can help decrease the risk of SE transmission. Cleaning before disinfection is essential, as it removes organic matter (dust, manure, spilled feed, and/or egg shells) and exposes the bacteria to the disinfectant so that it can be killed. Disinfectants are chemical that have the ability to kill bacteria on contact. By cleaning and disinfecting the poultry houses, egg producers are killing bacteria present in the environment and reducing the potential for the hens to become contaminated.
If the SE is present in the environment, the laying hen can become contaminated. If the hen contracts SE it can, very rarely, pass it on to the egg, living in the egg white and yolk. If SE is present inside the egg, prompt refrigeration after lay at or below and ambient (air) temperature of 45 °F significantly limits the growth of SE and lessens the potential for human illness. To ensure eggs are being held at the proper temperature, egg producers monitor daily coolers where the eggs are stored and the vehicles that transport them to the processing plant and stores after processing.