Why We Really Need to Refrigerate Eggs (and the British Don't)
To refrigerate or not to refrigerate — that is the question about eggs that several media outlets have been scrambling to answer in recent days.
The recent ovo-interest appears to have been whisked up by a Business Insider article in which writer Dina Spector wondered why we refrigerate eggs here in the United States while people in Europe and the U.K. are weirdly chill about chilling eggs, generally leaving them on the counter with the non-perishable foods. "Why doesn't anyone in the U.K. freak out over eggs sitting in room temperatures for days on end?" she demanded to know.
It turns out that the different approaches to refrigeration here and abroad stem from differences in the way eggs are treated to prevent salmonella poisoning during farming and processing.
In the U.K. in the late 1990s, after a spike in salmonella cases, farmers began routinely mass-vaccinating hens to prevent the spread of food-borne disease in eggs and poultry — an effort that has been credited with dramatically reducing laboratory-confirmed cases of salmonella from more than 18,000 in 1993 to only 459 in 2010.
Thanks to hen vaccination, which is required for eggs to get an industry-sponsored red lion stamp indicating they meet basic standards, "we have pretty much eliminated salmonella as a human problem in the U.K.," Amanda Cryer, director of the British Egg Information Service, told The New York Times in 2010.
Here in the U.S., however, hen vaccination is not mandated. Instead, government salmonella-prevention efforts center around the way the eggs themselves are handled. The FDA requires egg processers to follow specific sanitation procedures, regular testing and refrigeration.
USDA-graded eggs are washed and sanitized to rid them of bacteria at the packaging plant, and they are refrigerated "as soon as possible" after they are gathered from laying hens. "After eggs are refrigerated, they need to stay that way," the USDA website explains. "A cold egg left out at room temperature can sweat, facilitating the movement of bacteria into the egg and increasing the growth of bacteria. Refrigerated eggs should not be left out more than two hours."
Consumers themselves should not try to wash their eggs, the USDA warns. Doing so "may actually increase the risk of contamination because the wash water can be 'sucked' into the egg through the pores in the shell."
Refrigeration is especially important for hard-boiled eggs, because in the boiling process the protective coating put on the outside of an egg by an egg-laying chicken is damaged, exposing the pores in the shell to potential bacterial contamination. That's why hard-cooked eggs spoil faster than fresh eggs and, according the USDA, "should be refrigerated within 2 hours of cooking and used within a week."
Here are a few other egg-cellent egg-handling tips for consumers, from the USDA:
— Buy eggs marked Grade A or AA.
— Check that the shells are clean and uncracked. Don't purchase cracked eggs; bacteria can enter eggs through cracks in the shell.
— Make sure the eggs have been refrigerated in the store; bacteria can multiply quickly when eggs are left at room temperature.
— If you are purchasing egg products or substitutes, check to make sure containers are well sealed.
— Bring eggs directly home and store them in their carton, in the coldest part of your fridge (not the door) — at 40 degrees F or below.
— If an egg cracks while you're transporting it from store to home, break it into a clean container, cover tightly, and store in the refrigerator for use within two days.
— Before and after working with eggs, always wash your utensils and kitchen equipment, as well as your work area, with hot, soapy water.
— Never keep eggs unrefrigerated for more than two hours.
— Raw eggs and recipes that require them should either be cooked immediately or be refrigerated promptly and cooked within 24 hours.
— Eggs should always be cooked thoroughly before they are eaten; both the white and the yolk should be firm.
— Dishes that contain eggs should reach an internal minimum temperature of 160 degrees F. (Check with a food thermometer.)
— After you cook eggs or dishes containing them, serve immediately or quick-cool in a shallow container, refrigerate, and consume them within three or four days.
So while in the U.K., where the risk of salmonella is low, eggs do not need to be refrigerated (and, in fact, refrigeration is discouraged), we Americans do need to keep our eggs refrigerated — un-egg-quivocally.