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Why Most Americans Refrigerate Raw Shell Eggs and Europeans Often Don’t

American travelers to Europe may have noticed that people “across the pond” often store raw shell eggs at room temperature. They can safely do that because of the way eggs are produced in Europe, but it can’t be safely done in the U.S. because of Salmonella.

Salmonella bacteria, discovered in 1885 and named for the man who headed the U.S. Department of Agriculture (USDA) back then, can be transmitted via the outside of an egg if there is chicken manure present, or from inside the egg via the hen.

Salmonella infections are common in the U.S., causing at least 42,000 illnesses each year, according to the Centers for Disease Control and Prevention (CDC). However, CDC notes that the actual number of Salmonella-related illnesses is likely much higher since many people don’t seek health care for their symptoms.

Salmonellosis causes diarrhea, fever and abdominal cramps 12-72 hours after infection by the bacteria, symptoms usually last four to seven days, and most people recover without treatment. Some people, however, develop serious diarrhea requiring hospitalization, and Salmonellosis can be fatal if the infection spreads from the intestines to the bloodstream and other parts of the body — unless the person is promptly treated with antibiotics.

USDA requires raw shell eggs to be washed before they are sold. After being rinsed in hot water and dried, most large-volume processors then use a sanitizing rinse at the processing plant (this step is required for all USDA-graded eggs). Many processors then apply a light coating of food-grade mineral oil to the eggs to keep them from drying out.

In the U.K., the majority of egg producers vaccinate hens to help prevent Salmonella and generally do not wash or clean raw eggs before sending them to market because it may damage the shell, which can function as a barrier to pathogens. Their philosophy is to retain the thin coating called the “cuticle” that naturally occurs on the outside of the egg.

Refrigerating raw eggs is discouraged in the U.K. since the condensation that occurs after eggs are chilled and then warmed could potentially allow Salmonella bacteria to get inside the shell.

These egg production practices have reduced the incidence of Salmonella illnesses in Britain from 14,771 reported cases in 1997 to 581 cases in 2009.

Egg producers in the U.S. are starting to vaccinate laying hens more often than in the past, although the Food and Drug Administration (FDA) does not require it. After considering mandatory vaccination of hens for Salmonella in 2004, FDA concluded that the practice was promising but that “more information on the effectiveness of vaccines needs to be generated before we would mandate vaccination as a (SE) prevention measure.”

In 2010, a Salmonella outbreak that sickened at least 1,300 people in the U.S. was linked to eggs produced in Iowa. About 550 million eggs were later recalled in connection with that outbreak.

© Food Safety News
  • Keith Warriner

    In the late 1980;s there was extensive research into eggs after Edwina made her famous comments on the sanitary standards of the industry. The net result of the research was that the optimum method to store eggs was in the carton and refrigerated. Condensation is the main factor that defines the microbiological safety of eggs rather than storage temp. With respect to egg washing, research demonstrated that the practice was more likely to increase the risk of Salmonella. I would go against the hypothesis that UK eggs are Salmonella free – look back in the history of outbreaks

  • Richard Sprenger

    In the UK it is a requirement for eggs to be stored under refrigeration by the final user – the consumer or the caterer. We allow eggs to be transported and stored/displayed for sale below 20C as long for around 3 weeks from point of lay. The reason for this is that the natural antimicrobial properties of the egg prevent any salmonella that may be present internally from multiplying.
    It is interesting that when we were having major problems with salmonella food poisoning outbreaks they were all associated with products made with raw eggs which were not cooked or only lightly cooked, like mousse, mayonnaise, sauces and homemade ice cream. Other than temperature abused pooled scrambled egg I do not recall any UK reported proven outbreaks implicating soft fried or soft boiled eggs – despite all the hype. This is because the numbers of salmonella in clean, undamaged eggs within their shelf life was very small. I noticed the information from Australian outbreaks was similar.
    If your experience in the USA is different, and you are tracing outbreaks to “over easy eggs” perhaps this has something to do with the way they are washed etc.
    Richard Sprenger
    Chairman
    Highfield

  • NotMarkT

    The grass is always greener. According to EFSA (2014), the incidence of Salmonella in the
    UK is 14.3 per 100,000, and the incidence in the EU is 22.2 per 100,000. S. Enteritidis represented 41.3% of Salmonella serovars in the EU. According to CDC (2014), the incidence of Salmonella in the US is 15.2 per 100,000, and S. Enteritidis represented 19% of Salmonella serovars.

    EFSA (2014): http://www.efsa.europa.eu/en/efsajournal/pub/3547.htm
    CDC (2014): http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6315a3.htm?s_cid=mm6315a3_w

  • Dan

    It is my understanding that proper cooking would destroy any viable salmonella. Is it possible that Americans are more susceptible because they tend to eat undercooked eggs more often than Brits? Also, I thought widespread vaccination of livestock was discouraged in the US out of fear of antibiotic resistance?

    • Oginikwe

      Vaccinations are not the same thing as routine antibiotics.

    • J T

      The yolk of the egg is an almost perfect food, as long as it is consumed RAW! When the yolk is cooked, most of the beneficial vitamins are lost. The high cholesterol in the yolk is healthful for you when it is raw, but it becomes oxidated and artery-destroying when it is cooked! I have been eating conventional American eggs over-easy at least 4 times per week since I was a young child, and I have never been sickened by them! A healthy human stomach/body can successfully deal with a million individual cells of salmonella without becoming infected. Another tip is to eat the egg first before the rest of the meal, because your stomach acid will still be strong and not diluted by the other foods or starches in the meal.

  • Aleardo Zaccheo

    In regards to washing or not washing eggs, I recommend this document, very informative: The EFSA Journal (2005) 269, 1 of 39 Microbiological risks on washing of table eggs Opinion of the Scientific Panel on Biological Hazards on the request from the Commission related to the Microbiological risks on washing of Table Eggs (Question N° EFSA-Q-2004-031)
    Adopted on 7 September 2005

  • pawpaw

    Many Asians also lack our phobia for unchilled eggs. While living in Seoul, eggs we bought in the corner stores were not refrigerated. We bought just enough for that day or next morn, priced per each egg. While five months there, travelling widely, shopping and eating as Koreans, didn’t have a single case of gastrointestinal upset, even with 4 young children who ate all manner of foods throughout the country, including many room-temp eggs.

    In cultures where fresh foods are purchased and cooked same or next day, long term storage is less of an issue, hence refrigerators are fewer and smaller. NYT yesterday had an interesting piece on the growth of refrigeration capacity in China. How that is changing local food cultures, but also increased emissions to run all those compressors, and the inevitable leaks of refrigerants which are potent greenhouse gases. There is no free lunch, for various costs are higher as more ingredients are chilled as certain foodways become industrialized. Yes, sanitation matters in all settings; I know Asians who contracted polio while young.

    Here in the US, one can buy direct from farmers at local markets, including eggs gathered same or previous day. States vary on storage temps for eggs at market, but I’m unaware of requirements for washing when eggs not graded. We have customers who buy fertile eggs for hatching, and these we sell never refrigerated.

    In certain EU countries, their flocks have been declared salmonella free, in part due to vaccines also available here. And, we may purchase pasteurized eggs in our local groceries. These have their costs, but it’s doable. Those concerned about the risks of unpasteurized milk, are you working toward increased availability and use of pasteurized eggs and salmonella-free chickens? To protect children, with their heightened risk of salmonellosis? What dent could that make in reducing current CDC figs of 23K hospitalizations and 450 deaths per year? http://www.cdc.gov/salmonella/index.html