Eggs….. how to store them, how to check their freshness, the myths unraveled
“I don’t know anything about egg storage. I’m just astonished that people from the UK talk about whether you should keep eggs in the chiller. In the UK, room temperature is the same temperature as the chiller! ;-)”
-Tony Martin, Melbourne Australia, quoted in a forum on TheGuardian.com
It’s Easter Sunday today, so a post on eggs seems very appropriate! What gave me the idea to write on egg storage? Our lovely neighbours have chickens and have donated a large container of beautiful, fresh eggs. I thought it would be fine to keep them outside the fridge… but the Saucy Dressings’ Chief Taster wasn’t quite so sure. Which of us was right?
After the usual (unexpectedly extensive research) it turned out that there is a lot of uncertainty regarding how eggs should be treated and stored, how long for, and at what temperature. This includes the regulatory bodies of different nations (and their respective scientific advisors) disagreeing on the subject. Below is a summary of the advice available, but remember that no government guidelines or legislation (or information from any other source) can give 100% protection against food poisoning.
First things first: what temperature should your eggs be when you cook with them?
This is one of the easiest questions to answer. There are all kinds of advantages to cooking with room temperature eggs:
- It’s easier to beat eggs as room temperature – they mix together better.
- Room temperature eggs disperse more evenly when mixed into other ingredients – for example into cake mixes and batters. The result will be a lighter texture and a dish which will be cooked through more evenly.
- The yolks of refrigerated eggs are more likely to break when you fry them because of the greater change in temperature.
- Bear in mind that chilled eggs will take longer to boil, poach and fry.
- The shells are porous – it helps to keep them in their box, but any strong smells…cut onion or smoked mackerel for example… will insinuate themselves into the eggs.
- If you keep the eggs in the fridge, take them out half an hour before you intend to use them, otherwise the sudden change in temperature may lower their binding capability when used for baking.
- Remember that it’s easier to separate eggs when they are cold.
What are the best conditions for storing eggs?
- Eggs like a consistent temperature – the ideal is to keep them at a temperature below 20°C (this figure comes from the Egg Info site). If you have a shop or market, or you are lucky enough to have a separate larder, outside your kitchen, where the temperature is below 20°C you can keep your eggs out of the fridge; but for most domestic use it’s easier to keep the eggs in the fridge.
- However, bear in mind that refrigerating the eggs will reduce their quality, in particular they lose their elasticity.
- Once you have been keeping your eggs in the fridge, you can’t take them out and store them on your worktop for much longer than a couple of hours because the temperature change can cause the egg to sweat or condense, encouraging bacteria growth in the moisture. For the same reason, there are advantages to buying eggs kept out of the fridge in a supermarket with an ambient temperature of less than 20°C because there will be less of a temperature fluctuation resulting in the process of putting them in a hot car and taking them home.
- Because eggs benefit from consistent temperature it’s not a good idea to keep them in the fridge door, the part of the fridge which is warmest and most likely to see temperature changes. Ideally keep your eggs at the back of the middle shelf of the fridge.
- Don’t wash your eggs – the shells are porous remember – bacteria can creep in via the water you use.
- But bear in mind that the bacteria has to permeate the cuticle, and two membranes of super-tough keratin.
- As we mention above, egg shells are porous. Don’t be tempted to decant your eggs into the plastic holders supplied with the fridge, or into some other, open, container. Keep them in their boxes which will help to protect them against strong smells (as we mention above) and keep them away too from raw meat, to avoid cross contamination.
- If you keep the eggs in their box, you will be able to see the Best Before label more easily.
- Store the eggs with the large end up. This will encourage the yolk to remain in the centre. When the yolk begins to touch the inner membrane the egg will start to go off.
- Don’t use cracked eggs – again, the natural protective seal that eggs have will be broken, and a gateway for bacteria to march in has been opened up.
- Bear in mind that the lower temperature of the fridge doesn’t kill all bacteria. Keep your fridge, your hands, and your utensils clean.
How long will eggs keep?
Be guided by the Best Before date, but from fresh eggs will last up to three weeks (broadly, the incubation period – see paragraph below, The Best Solution) in a cool, dark pantry; and up to seven weeks in the fridge.
The best solution
Ideally you don’t want to store your eggs in the fridge; you want to store them for a couple of weeks (ideally a week) in a cool, dark place, ideally a proper larder (or maybe your wine cellar), separate to the kitchen, at a constant temperature. However, remember that unhatched chicks have survived on the nourishment offered by the egg, at higher temperatures than ambient (warmed by the chicken sitting on them) for their incubating period of three weeks for centuries. Quail eggs take about 18 days to incubate, and duck eggs about 28 days. But shell thickness also has an impact – duck eggs will keep longer than their incubating period because they have an incredibly hard shell – much thicker and harder than a hen’s egg, as anyone who has tried to break one will attest.
In any case, buy what you need on a weekly basis.
If you are keeping your eggs in a cool larder, and constantly replenishing your stock, use an egg skelter, which will ensure you always use the oldest eggs first.
However, if you are given a generous quantity of eggs, as we were, more than you can eat in a couple of weeks, the best thing to do is to put them into used (clean) egg boxes and keep them in the fridge on the middle shelf towards the back.
If you are being given eggs by a friend, or if you are buying them on a market stall and there is no British Lion stamp the hens producing the eggs may not have been vaccinated.
What is salmonella enteritidis, and why is egg treatment (both pre and post purchase) so critical?
Chickens and hens are particularly vulnerable to becoming infected by the salmonella bacteria. Symptoms of salmonella in humans are very unpleasant, including fever, diarrhoea, stomach cramps and vomiting. Most sufferers recover within a week or so, but, particularly if it spreads to the bones or blood, the results can be fatal, especially for children, pregnant women and the elderly.
The salmonella bacteria can enter the egg in two ways: either the hen laying the egg already has the bacteria; or, post laying, the egg can come into contact with the bird’s faeces, or other sources of bacteria.
For a truly informative article on salmonella, go to the Connect For Water blog.
Why the Americans have a very different approach to storing eggs to Europeans…and why is the British approach (as usual!) different again?
In the US the Department of Agriculture (the USDA) imposes regulations which require eggs to be washed and sprayed with chemicals. In fact, it’s not just the eggs they like to wash, but the chickens too – see Transatlantic Trade and Investment Partnership; Love Or Dread? .One reason given for this (to be confirmed) is that there are a lot more battery hen facilities in the US than in the UK where there is more free range egg and chicken production. Less land is needed for battery hens, and inevitably they are keep closer together, with contamination being easier. The USDA recognises that this needs to be done with care. “Wetting a dirty shell provides moisture in which bacteria may breed and assists their growth and penetration through their shell” they warn in their published egg grading manual. But, in their view, egg washing with chemicals is the best way to reduce the risk of salmonella to the public. The temperature of the wash is also important. The washing solution needs to be a minimum of 32.2°C in order to prevent the egg contracting a little as it cools and thereby drawing dirty water in through the shell.
The US Department of Health and Human Services still rates salmonella as one of the top six causes of food poisoning in the USA.
In Europe (including the UK)
In Europe the approach is the opposite: washing is considered to be a way of enabling harmful bacteria to transfer from the outside to the inside of an egg.
There is a concern about the damage done by washing to the cuticle of the egg, which is soluble. The cuticle (sometimes known as the ‘bloom’) is the outer coating of the shell, it seals the pores preventing both moisture loss and bacteria ingress. It’s on this cuticle that different pigments are deposited as the egg travels down the hen’s oviduct – this is the reason why egg shells can be blue, brown, green…even pink (follow this link to find out exactly how this happens, and why the flavor is not affected). Over time (and particularly at lower temperatures) the cuticle can dry off, so sailors who want to make their eggs last longer often cover them in a layer of Vaseline to replace the seal provided by the disintegrating cuticle. Without the waxy seal of the cuticle the egg itself can start to lose moisture and oxygen.
Additionally, under the shell there are two further coatings, both made of keratin, protecting against external infection. Keratin is a very tough protein which also forms hair, nails, claws, horns and scales. There is the outer membrane, which is attached to the shell; and the inner membrane, which is attached to the egg white.
Bearing all that in mind the European view that dealing with the infection issue by washing is like to be shutting the stable door after the horse has bolted seems very reasonable – it’s better to ensure the eggs are bacteria-free in the first place, as the egg itself has a number of effective protective barriers against infection.
This approach has the added advantage of discouraging the harsh battery farm techniques and encouraging an economic concern for animal welfare.
Standards vary between European countries. In 2006 one in thirty boxes of eggs from the continent was found to contain salmonella bacteria, with one in eight boxes from Spain being infected.
Specific to the UK
In Britain we have much to thank Edwina Currie, a junior health minister. On 3 December 1988 this lady announced on television that “most of the egg production in this country sadly is now infected with salmonella.”.
The effect on the egg industry was devastating and immediate. Egg consumption fell by 60%, 4 million hens were slaughtered, and 40 million eggs had to be destroyed. There was a big outcry and Edwina Currie ended up by having to resign as it transpired she had exaggerated the problem. Why did she do it? She was genuinely very concerned – salmonella infection levels really had trebled in a year – and she felt she needed to make a stand.
She achieved increased public awareness of the problem, and therefore increased care taken by the industry, but the real change came ten years later when chicken farms began to vaccinate their hens under the British Lion scheme. See the interview with her at the bottom of this post for more on this.
The British Egg Industry Council’s Lion Code of Practice introduced not just vaccinations, but also increased hygiene control and salmonella testing, as well as stamping the Best Before date on the individual eggs as well as the box. In November 2013 Edwina Currie described British eggs as the safest in the world, and by 2017 more than 90% were covered by the Lion scheme. On 11 October 2017 the Food Standards Agency changed its advice on eggs, declaring them to be safe to be eaten runny, or raw, by everybody, even vulnerable groups of people.
What are the regulations for caterers, restaurateurs and retailers?
Helpful guidelines outlining regulations in Ireland are available on the Food Safety Authority of Ireland site.
For the UK regulations, follow this link.
How to tell how fresh your egg is
Eggs have a small air bubble between the inner and outer membranes which forms at the wide end. As the egg ages this air bubble increases in size. A fresh egg will sink to the bottom of a glass of water. One which is really past its best, and best thrown out, will float on the top.
If you notice that the egg white is a bit cloudy, don’t panic! It actually means the egg is very fresh because it’s formed by the high carbon dioxide content on laying.
Equally, the fresher the egg, the more prominent will be the twisted cords of the chalaza whose purpose is to keep the yolk centred. By a miracle of nature the cords at top and bottom of the egg twist in different directions to retain tension, the yolk suspended between them.
Storing hard-boiled and poached eggs
Hard boiled eggs can be kept in the fridge for up to a week.
Pre-poached eggs can be kept for a couple of days (the less long the better). You’ll need to dunk them in some gently simmering water for about a minute before you use them.
Storing egg whites and egg yolks separately
• If you have any leftover yolks you can store them in the fridge, just covered with a little cold water, and then clingfilm – but use them within 2-4 days.
• You can also store egg whites in the fridge in airtight containers for the same period. And you can freeze egg whites. Freeze each white separately in an ice cube tray (transfer to another container later if you wish), otherwise allow two tablespoons of egg white to substitute for one fresh egg white.
Many thanks to @theeveningcoffee for their comment, “Wow! I’ve never learned that much about eggs than in the last five minutes when I was reading the article.”
Below you can watch a video of Edwina Currie talking to The Grocer about egg safety nowadays.