Why are eggs perishable

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.

As Salmonella treatment varies by country — as detailed below — refrigerating eggs may be necessary in some regions but not others. Salmonella is a bacterium that commonly causes foodborne illnesses. How countries treat eggs for Salmonella determines whether they need to be refrigerated. Before eggs are sold, they undergo a sterilization process.

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 , 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. 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. Many European countries do not refrigerate their eggs, even though they experienced the same Salmonella epidemic during the s. 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 , 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 Fielder believes that refrigeration is related to "whether local advice recommends this practice or not.

Dirty eggs may be stored in temperatures of up to After an egg is refrigerated, it must be kept at that temperature. That's why the Centers For Disease Control and Prevention recommends that US consumers keep eggs refrigerated at temperatures of 40 degrees F — to prevent illness from bacteria. But there's another reason the UK is not as concerned about washing eggs as the US: Salmonella is not as big of a health concern in Britain.

Egg farmers began vaccinating their hens in , after thousands of people were sickened by the bacteria. Although vaccination has been linked to a rapid decline of salmonella cases in the UK , US regulators have still not mandated immunisations, although many of today's eggs producers do vaccinate their hens.

In , the FDA said it would not legally require the vaccination of hens because "there was not enough evidence to conclude that vaccinating hens against salmonella would prevent people from getting sick," The New York Times reported. Farmers also complained that it would be expensive.

Instead, the FDA controls the threat of salmonella through regular testing, refrigeration standards, and strict sanitary codes in hen houses and processing areas, The Times said. The organisation estimates that more than , people get sick each year from eating eggs contaminated with the bacteria, which triggers non-life-threatening though unpleasant symptoms like diarrhoea, cramps, and vomiting.

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Find out now! Samantha Ruth Prabhu's revenge dressing game is on point. But at a French grocer or a British supermarket? On the other hand, most European and Asian countries have reached the opposite conclusion , requiring that table eggs not be wet-washed, and also not refrigerated.

Both regulations were arrived at as effective ways to solve the same problem: reducing exposure to salmonella, a bacteria that causes unpleasant, though non-life-threatening, illness. Yet those of us accustomed to refrigerating our eggs might find it hard to believe that eggs stored at room temperature are safe to consume. Food poisoning is no fun, after all. Eggs can be infected by salmonella in one of two ways : First, bacteria can be passed from an infected hen to her eggs as they develop inside her.