How long can eggs that I washed at home last in England at room temperature?

Question

Related to my previous question, a follow-on corollary: I rinsed off every one of my 2 dozen eggs and put them into a carton on the kitchen counter. How long now may they last?

Answer 1

When I read the information on egg storage, it doesn't appear as clear cut as some folks suggest. Washing or not....refrigerating or not...the Internet advice is mixed, with lots of folks conflating opinion, common practice, myth, and science.

Let's start with washing. In this study, the author's state:

Statistical analysis of the agar penetration experiment indicated that S. Typhimurium was able to penetrate washed eggs at a significantly higher rate when compared to unwashed eggs (p<0.05). When compared to unwashed eggs, washed eggs also had significantly damaged cuticles.

The implication is that washing increases the likelihood that pathogens (salmonella is the main pathogen of concern) from the shell surface can pass through the shell and contaminate the egg.

Those who suggest washing for the purpose of reducing potential pathogens on the surface, recommend wash water of at least 20ºF (~11ºC) higher than the temperature of the egg, to reduce the opportunity for inward capillary action. It is suggested that egg washing reduces risk, but must be done properly. If you dramatically reduce the pathogen from the surface, the risk of pathogens entering the egg is obviously dramatically reduced.

To refrigerate or not seems to be a separate, but related, question. In the US it is required that all eggs commercially produced be at or less than 45°F [7°C] soon after laying and throughout the distribution system. In Europe, however, this is not the case. It has less to do with washing than it does with a concern about condensation when eggs go from warm to cold environments. However, the linked document states there is no research to support the hypothesized risks associated with condensation.

In Europe the procedure is that eggs be kept "cool… 66.2°F [19°C] to 69.8°F [21°C] in the winter and 69.8° [21°C] to 73.4°F [23°C] in the summer," or slightly below room temperature. "...Possibly because Britain requires vaccination against salmonella enteritidis." So, the likelihood of salmonella contamination is considerably less in Europe than in the US, where this vaccination is not required.

Salmonella does not only exist on the exterior of the shell, as contaminated birds can pass along salmonella in their eggs. In this case, washing or not wouldn't matter because salmonella is already in the egg. For reference, in the US, the Centers for Disease Control estimate 1 in 20,000 eggs is contaminated with salmonella.

The bottom line is that, as least as far as I can tell, (a) there is no definitive science on the washing and refrigeration question, and (b) suggesting that washed eggs from backyard chickens, or washing eggs in general, now have a non-refrigerated shelf life of 2 hours seems incredibly conservative.

I suggest the 2 hours is conservative because if your chickens have salmonella and the eggs also contain salmonella, I can imagine them being in the chicken coop for much longer than 2 hours before they are even collected. So, washing wouldn't matter...and when would you start the clock? Plus, temperatures of 140F [60C] to 149F [65F] is sufficient to kill salmonella. So, cooking your eggs well manages this risk.

If there is salmonella on the exterior only, because some chicken excrement or debris got on the eggs, not washing them could be problematic because the likelihood the interior gets contaminated during cracking is probably higher. So, washing them correctly actually reduces the risk by dramatically reducing the potential for pathogens to move from the shell to the egg.

It seems like the most important factor is how likely salmonella is present in the flock (which something you may not be able to assess), and how well you cook your eggs (to kill potential salmonella).

The most conservative advice is to simply refrigerate your eggs, but it is unclear that unrefrigerated eggs, correctly washed or unwashed, are riskier than refrigerated eggs. However, regardless of pathogen risk, refrigeration significantly extends shelf life in terms of quality, making it advantageous if you keep eggs around for a while.

Answer 2

Unless somebody discovers a special-case regulation to the contrary, this defaults to the case of a "keep refrigerated" item stored at room temperatures. The storage time for washed eggs at room temperature is 2 hours.