Egg washing has been a well-established practice for more than 40 years in countries such as the United States, Canada, Australia, Japan, and Sweden, where authorized or licensed egg packing centers wash table eggs or eggs destined for the egg products sector under supervised conditions.
Egg washing also formed part of the Codex Alimentarius Code of Practice for Eggs and Egg Products adopted in July this year, Henry Kuhl of the U.S.-based Kuhl Corp. said at the International Egg Commission conference in Budapest, Hungary.
"When table eggs are washed under these regulations they would still be classified as Class A," he said. "As regulators are increasing food safety awareness, egg washing is receiving renewed attention in countries where it is not yet allowed."
However, he stressed, "If well done, there are clear advantages to egg washing because of the reduced microbial load, but Kuhl admitted that poor practices increase the risk." Non-washed eggs have on average 31,000 counts of shell-borne bacteria, but when washed and sanitized, this count could be reduced by between 90 to100 percent.
"A continuous commercial washing system will remove salmonella and most other disease-causing bacteria and viruses on the shell and is complimentary to other egg safety schemes such as flock vaccination," he asserted.
Regarding the procedure, Kuhl said that the only economical way to provide warmed wash water with detergent is to filter and re-circulate it, thus proper filter trays must be provided as part of the system. Because the openings in the filter screens are smaller than the openings in the spray nozzles, the incidence of plugged spray nozzles is substantially reduced.
The recommended time for eggs in the wash chamber is 45 to 60 seconds. The use of a detergent concentrate differs from area to area depending on the softness or hardness of the water. In some instances a defoamer is needed because of the soil load in the wash water.
Crucially, a ph of 10 to 11 is recommended to eliminate shell borne salmonella and other microorganisms. Washed eggs are spray rinsed with water having a temperature equal to or warmer than the wash water in order to maintain a positive pressure inside the eggs.
Kuhl said the benefits of using continuous commercial capacity egg washers are:
- Eggs could be washed inline or offline, even at seven days after lay,
- It removes 99.98 percent of shell-borne bacteria including salmonella enteritidis,
- Bacteria counts could be reduced from 31,000 to 50 after washing,
- The inner membrane is expanded preventing anything from entering the shell,
- It improves egg shell appearance and user acceptance,
- Seventy-five percent of the labor required to pick out dirty eggs from incoming conveyor lines is eliminated,
- No extra labor is needed to operate the egg washer connected to egg graders or breakers,
- By keeping egg graders, packers and plants cleaner, less labor is required for clean up,
- Leaking eggs are washed out and not delivered to the grader, but sound eggs pass through undamaged,
- When choosing not to wash, an outside lever allows the system to become a dry conveyor,
- If the proper ink is used for stamping free-range eggs, it will not be washed off,
- Eggs can be oil-sprayed if requested, though since the cuticle was not removed, oiling isn't necessary, and
- It provides for improved food safety and reduces the cost of processing the eggs.