While most Americans store eggs in the fridge, many Europeans do not. This is because authorities in most European countries say refrigerating eggs is unnecessary. But in the United States, it is considered unsafe to store eggs at room temperature. As such, you may wonder about the best way to keep eggs. This article tells you whether eggs need to be refrigerated. Share on Pinterest

It’s all about Salmonella Salmonella is a type of bacteria that lives in the intestines of many warm-blooded animals. It’s perfectly safe when contained within the animal’s intestinal tract but can cause serious illness if it enters the food supply. Salmonella infections can cause unpleasant symptoms like vomiting and diarrhea and are especially dangerous — even fatal — for older adults, children, and those with compromised immune systems ( 1 ). Common sources of Salmonella outbreaks are alfalfa sprouts, peanut butter, chicken, and eggs. In the 1970s and 1980s, eggs were determined responsible for 77% of Salmonella outbreaks in the United States ( 2 , 3 ). This prompted efforts to improve egg safety. Infection rates have since decreased, although Salmonella outbreaks still occur ( 3 ). An egg can be contaminated with Salmonella either externally, if bacteria penetrate the eggshell, or internally, if the hen itself carried Salmonella and the bacteria were transferred into the egg before the shell formed ( 4 ). Handling, storage, and cooking are essential to preventing Salmonella outbreaks from contaminated eggs. For example, storing eggs below 40°F (4°C) halts the growth of Salmonella, and cooking eggs to at least 160°F (71°C) kills any bacteria present. As Salmonella treatment varies by country — as detailed below — refrigerating eggs may be necessary in some regions but not others. SUMMARY Salmonella is a bacterium that commonly causes foodborne illnesses. How countries treat eggs for Salmonella determines whether they need to be refrigerated.

Refrigeration necessary in the United States In the United States, Salmonella is mostly treated externally. Before eggs are sold, they undergo a sterilization process. They’re washed in hot, soapy water and sprayed with a disinfectant, which kills any bacteria on the shell ( 5 , 6 ). A handful of other nations, including Australia, Japan, and Scandinavian countries, treat eggs the same way. This method is highly effective at killing the bacteria found on eggshells. However, it does nothing to kill bacteria that may already be present inside the egg — which is often what makes people sick ( 5 , 6 , 7 ). The washing process may also remove the cuticle of the egg, which is a thin layer on the eggshell that helps protect it. If the cuticle is removed, any bacteria that come into contact with the egg after sterilization will more easily be able to penetrate the shell and contaminate the contents of the egg ( 8 , 9 ). While refrigeration does not kill bacteria, it reduces your risk of sickness by limiting the number of bacteria. It also impedes bacteria from penetrating the eggshell ( 10 , 11 ). Nonetheless, there’s another important reason that eggs must be refrigerated in the United States. To keep bacteria to a minimum, the Food and Drug Administration (FDA) requires commercially sold eggs to be stored and transported below 45°F (7°C). Once eggs have been refrigerated, they must be kept refrigerated to prevent condensation from forming on the shell if they warm up. This moisture makes it easier for bacteria to penetrate the shell. Thus, any commercially produced eggs in the United States should be kept in your fridge. SUMMARY In the United States and a few other countries, eggs are washed, sanitized, and refrigerated in order to minimize bacteria. Eggs in these nations must remain refrigerated to minimize the risk of contamination.

Refrigeration unnecessary in Europe Many European countries do not refrigerate their eggs, even though they experienced the same Salmonella epidemic during the 1980s. While the United States implemented regulations for egg washing and refrigeration, many European countries improved sanitation and vaccinated hens against Salmonella to prevent infection in the first place ( 12 , 13 ). For example, after a program in the United Kingdom vaccinated all egg-laying hens against the most common strain of this bacterium, the number of Salmonella cases in the country dropped to their lowest level in decades ( 13 ). Contrary to the United States, washing and disinfecting eggs is illegal in the European Union. However, Sweden and the Netherlands are exceptions (14). While this may seem unsanitary to Americans, the egg cuticle and shell are left undamaged, functioning as a layer of defense against bacteria ( 4 ). In addition to the cuticle, egg whites also have natural defenses against bacteria, which can help protect the egg for up to three weeks ( 4 , 15 ). Therefore, it is considered unnecessary to refrigerate eggs in much of Europe. In fact, the European Union recommends that eggs be kept cool — but not refrigerated — in supermarkets to prevent them from warming up and forming condensation during your trip home. Because eggs from the European Union are treated differently than U.S. ones, it’s fine to keep eggs out of the refrigerator in much of Europe as long as you plan to use them soon. SUMMARY In most European countries, Salmonella is kept under control with preventative measures like vaccination. Farms are usually not allowed to wash eggs, so the cuticles remain intact, precluding refrigeration.

Other pros and cons of refrigeration Even though you may not need to refrigerate your eggs, you may want to do so depending on your location. While refrigeration has some benefits, it also has drawbacks. Below are the pros and cons of egg refrigeration. Pro: Refrigeration can double an egg’s shelf life Storing your eggs in the fridge is the best way to keep bacteria under control. As an added bonus, it also keeps eggs fresher for much longer than storing them at room temperature. While a fresh egg stored at room temperature will start to decline in quality after a few days and need to be used within 1–3 weeks, eggs kept in the refrigerator will maintain quality and freshness for at least twice as long ( 15 , 16 , 17 ). Con: Eggs can absorb flavors in the fridge Eggs can absorb odors and flavors from other foods in your fridge, such as freshly cut onions. However, storing eggs in their carton and sealing foods with strong odors in airtight containers can prevent this occurrence. Con: Eggs shouldn’t be stored in the fridge door Many people keep their eggs in their fridge door. However, this can subject them to fluctuations in temperature every time you open your fridge, which could encourage bacterial growth and impair the eggs’ protective membranes ( 4 ). Therefore, keeping eggs on a shelf near the back of your refrigerator is best. Con: Cold eggs may not be best for baking Lastly, some chefs claim that room-temperature eggs are best for baking. As such, some suggest letting refrigerated eggs come to room temperature before use. If this is important to you, it’s considered safe to leave eggs at room temperature for up to two hours. Still, you should be sure to cook them to a safe temperature ( 18 ). SUMMARY Refrigeration keeps eggs fresh for more than twice as long as eggs kept at room temperature. Yet, they must be stored properly to prevent taste and temperature changes.