Advice about washing eggs - risks, do's and don't's
Is it illegal to wash my eggs before sale?
With the exception of Class A hen eggs, washing of eggs is permitted under food law.
The egg marketing rules stipulate that Class A hen eggs may not be washed. Only Class B hen eggs may be washed and these cannot be sold at retail, but to other food businesses where they will be processed. The marketing rules only apply to hen eggs.
Is washing of eggs recommended?
No, because washing may aid the transfer of harmful bacteria like Salmonella from the outside to the inside of the egg.
The priority in egg production is to produce clean eggs at the point of collection, rather than trying to clean them afterwards. The cleanliness of the egg should be assured by good management and hygiene of the poultry house, and by minimising the delay between egg laying and egg collection.
What are the risks associated with washing eggs?
Egg laying poultry (e.g. hens, ducks, geese) can be infected with Salmonella and other harmful microorganisms. Salmonella bacteria cause sickness, and in some people the illness can be severe and life-threatening. If egg laying poultry are infected with Salmonella, they can shed these bacteria in their faeces. If care is not taken in egg production, then the eggs can become soiled with faeces – and therefore Salmonella can be found on the shell. During washing, the natural barriers in the shell can be compromised and Salmonella may pass into the inside of the egg where it has the opportunity to grow. Sometimes, Salmonella can grow to very high numbers inside eggs and if these eggs are not cooked thoroughly (e.g., in the case of runny fried or boiled eggs or in desserts such meringue or tiramisu), the Salmonella survive and cause consumers to get sick.
What are the risks associated with not washing eggs?
Salmonella can survive for a long time in dried faeces on the outside of eggs. This presents two risks. Firstly, if eggs are stored incorrectly and condensation forms on the shell, the water may be sufficient to allow Salmonella to pass into the inside of the egg through the pores in the shell. This risk increases over the storage time, as the natural barriers of the egg start to break down with increasing age of the egg. Condensation on the outside of eggs also increases the chance that Salmonella on the shell may grow. Secondly, during handling and preparation of dirty eggs, direct hand-to-mouth contamination can occur, or other foods may be cross-contaminated from hands, dirty discarded shells, or during the action of cracking the egg.
What if my eggs are dirty and my customer demands clean eggs?
Remember egg washing is not recommended because Salmonella can move into the inside of the egg through pores in the shell, increasing the risk to consumers. Try to explain this to your customer and get agreement to accept unwashed eggs.
There is an increased risk of Salmonella transmission from the outside to the inside of eggs during washing. These risks can be multiplied several-fold by poor washing practice. For example, if soiled eggs are left uncollected for a few hours after laying, and/or if they are left to soak in wash water, then there is more time for the Salmonella to pass through the shell into the egg. Additionally, if the washing water is not at least 11o C above the temperature of the egg, then Salmonella can be sucked into the egg through the pores in the shell. Even after washing, if eggs are not dried quickly and completely before storage then there is more chance of Salmonella penetrating the shell. The use of chemical detergents or sanitisers in the wash water may not help, because some chemicals may actually increase the porosity of the shell making it easier for Salmonella to cross the shell barrier.
Getting egg washing right to avoid all these increased risks is not simple, and for that reason it is much safer not to wash them at all, but to concentrate on good husbandry, and the production of eggs that are clean in the first place.