To Refrigerate or Not!

How Long Can Eggs Go Unrefrigerated? British vs. American Egg Keeping

To Refrigerate or Not!

Reading Time: 6 minutes

Susie Kearley – In the United Kingdom and Europe, many people keep their eggs at room temperature. The supermarkets sell unrefrigerated eggs, and it’s thought that refrigerating eggs in shops is bad practice because chilling the eggs and then allowing them to warm on the way home could create condensation. Damp makes it easier for salmonella to penetrate the shell, so you could end up with infected eggs.

In the home, many Brits continue to store their eggs at room temperature, saying that unrefrigerated eggs taste better, are less likely to absorb the flavors of other foods, and cooking times are more predictable. However, some Brits put them in the fridge because, like most fresh and perishable produce, chilled eggs do stay fresher for longer than unrefrigerated eggs. It can be a bit of a dilemma!

Why, then, do people in the United States refrigerate their eggs so consistently? The risk of salmonella is higher in the United States. Let me explain …

Poultry Farming Methods

Eggs are refrigerated soon after they’re laid in the United States because it’s a necessary precaution against salmonella infection, according to the United States Department of Agriculture (USDA). Salmonella is a bigger problem in the United States than in Britain because American chicken farmers follow different methods of production to their counterparts in the United Kingdom, where salmonella has been virtually eliminated. Salmonella can infect an egg either directly from an infected hen, or from the bacteria penetrating the egg from outside, perhaps from contact with the hen’s feces.


In the United Kingdom, commercial chicken flocks are vaccinated against salmonella. This reduces the risk of infection significantly. Any risk of contamination from outside is also kept to a minimum because the cuticle, a naturally occurring protective coating, is left intact around the eggshell. Many flocks in the United Kingdom are free-range (only going into barns for the night), so their eggs are less likely to get dirty than in the United States where hens are more often kept in barns with less space to roam. 90 percent of British eggs subscribe to the Lion Scheme, whose code of practice includes salmonella vaccination; traceability of hens, eggs, and feed; hygiene controls; stringent feed controls, and independent auditing.

The United States Egg Production System

In the United States, there’s a focus on preventing contamination from the outside by washing eggs. So each egg is washed in hot water, then dried and sprayed with a chlorine mist. The water must be at least 89.96 degrees to prevent the egg from contracting and absorbing contaminants from outside the shell as it cools. Washing an egg removes its natural protective coating, but as the eggs are cleaned soon after they’re laid, the process is supposed to help prevent contamination. The United States food safety regulations then require refrigeration, so unrefrigerated eggs are forbidden in the United States supply chain. However, despite these efforts, around 140,000 people are poisoned by salmonella-infected eggs in the United States every year. The USDA is working to reduce this figure.

Washing Eggs: Good or Bad?

In Europe, washing off the egg’s natural protective coating is thought to increase the risk of salmonella poisoning, because it makes it easier for bacteria to penetrate the shell. As eggs sold in British supermarkets aren’t washed — it’s not allowed — there’s an incentive for British farmers to keep their chicken sheds clean, which is good for hen welfare too. So the European approach to egg production encourages conscientious attention to cleanliness and hygiene in egg production. A messy environment would produce messy eggs, which can’t legally be washed before sale.


Immunization in the United States

Immunization in the United Kingdom has had a hugely positive impact — helping to virtually eliminate salmonella in eggs. So some United States producers are immunizing their flocks too, although some farmers still say it’s too costly.

While there’s no legal requirement to immunize flocks in the United States, the Food and Drug Administration does insist upon regular salmonella testing, refrigeration, and adherence to strict sanitary codes in hen houses.

To reduce the risk of infection by consumers, the USDA strongly recommends thorough cooking of eggs as this kills the salmonella bacteria, making eggs safe for consumption. They say you should never eat raw eggs or raw egg products. The salmonella bacteria can spread rapidly at room temperature, which is why commercially-produced eggs are refrigerated by law in the United States. Keeping unrefrigerated eggs in the United States then is probably a bad idea.

Backyard Flocks

You might think that backyard flocks don’t carry the same risks as commercial chicken farms. However, the Centers for Disease Control and Prevention (CDC), and the USDA say there is still a risk. They’ve investigated 961 cases of salmonella in humans linked to backyard chicken flocks, across 48 states. These infections, which took hold over the seven month period between January 4 and July 31, 2017, resulted in 215 hospitalizations and one death.

The CDC suggests that backyard chicken keepers take the following precautions: “Live poultry, such as chickens, ducks, geese, and turkeys, often carry germs such as salmonella. After you touch a bird or anything in the area where birds live and roam, wash your hands so you don’t get sick!”


Children and the elderly, or people with compromised immune systems are at greater risk of infection. The CDC continues, “Live poultry might have salmonella germs in their droppings and on their bodies (feathers, feet, and beaks), even when they appear healthy and clean. The germs can get on cages, coops, feed and water dishes, hay, plants, and soil in the area where the birds live and roam. Germs also can get on the hands, shoes, and clothes of people who handle or care for the birds.”

It’s hard to be sure whether your chickens carry the disease; there are no signs of illness and it can be easily transmitted from bird to bird, so following the advice of the authorities is a sensible precaution.

Eating unrefrigerated eggs may increase your risk of salmonella infection, even from your own backyard flock, so it’s best to refrigerate. Duck eggs carry the same risks, unfortunately, so refrigerate them too.


The CDC Recommends:

• Wash your hands thoroughly after touching the chicken coop.
• Don’t bring your chickens into the home, especially the kitchen, pantry, or dining room.
• Keep shoes for tending to your flock, separate from your other shoes.
• Don’t let anyone with a developing or weakened immune system touch the flocks or their housing.
• Don’t eat where the birds roam.
• Don’t kiss your birds or touch your mouth after handling them.
• Clean all the chickens’ equipment outdoors.
• Source your hens from hatcheries that subscribe to the U.S. Department of Agriculture National Poultry Improvement Plan (USDA-NPIP) U.S. voluntary Salmonella Monitoring Program [279 KB]. It’s designed to reduce the risk of salmonella in chicks.

How Long Do Eggs Keep?

Refrigerated, eggs will typically keep for four to five weeks, sometimes longer. Unrefrigerated eggs have a shorter life and this will depend on the temperature in the home, but as eating unrefrigerated eggs is not recommended in the United States, it’s better to pop them in the fridge anyway. If in doubt about the freshness of your eggs, you can do an egg freshness test; essentially, if the egg sinks in water, it’s fine! If it floats, it’s rotten!


Making Sure Your Eggs are Properly Cooked

It’s long been said that anyone who’s vulnerable or has a compromised immune system should cook their eggs thoroughly to prevent salmonella poisoning. Some people argue that if a chilled egg is cracked into a frying pan, after a few minutes, the runny yolk may look perfect, but it may not have reached a high enough temperature to kill any salmonella bacteria present. It’s important then, to make sure your egg is piping hot before consuming it. Often experts will say eggs are best avoided by pregnant women altogether, as a precaution.

You may feel confident that your flock is salmonella-free and that’s great, but as salmonella is the biggest cause of food poisoning in the United States, it’s better to be safe than sorry!


  • Shell Eggs from Farm to Table | Food Safety and Inspection Service (

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