In supermarkets across the United States,
Australia, and Japan, eggs can be found in the refrigerated section alongside other cold
items such as milk and cheese. However, in most other countries of the world,
eggs can be found stored at room temperature alongside nonperishable food items. People eat both kinds of eggs every day, usually
without any ill effects. So why do some people refrigerate eggs and
others don’t? The answer lies in the bacteria group known
as salmonella and how a particular country chooses to make sure their eggs don’t get
contaminated with it. Salmonella enters eggs through one of two
ways- via contaminating the egg internally before the hen lays it (when a hen’s ovaries
have been infected); or via the porous egg shell (when an egg comes in contact with contaminated
matter such as chicken manure). Egg producers in the United States address
the salmonella problem with eggs by concentrating on preventing the bacteria from entering through
the shell. Towards this end, the United States Department
of Agriculture (USDA) mandates that all eggs be washed with water at a minimum temperature
of 90 degrees Fahrenheit and at least 20 degrees warmer than the internal temperature of the
egg at the time of washing. (If it were colder than the egg, this could
result in a very slight contraction, sucking in contaminated water through the shell’s
pores). The eggs will also be washed with some form
of detergent and chemical sanitizer like chlorine, then are rinsed again and thoroughly dried-
the latter further helping make sure pathogens can’t easily find their way through the
egg’s thousands of pores. After this, the eggs are often sprayed with
some form of protective coating like mineral oil. Finally, the eggs are taken into a room where
they are stored at temperatures at or below 45 degrees Fahrenheit. This effectively deals with the external sources
of salmonella (and helps ensure you won’t accidentally contaminate other foods with
salmonella from touching a contaminated egg shell then touching other items as you prepare
food). However, this does nothing to destroy any
salmonella potentially already present within the egg. This is where the refrigeration comes in. By keeping the eggs sufficiently cold, it
mostly makes sure any salmonella present will not multiply sufficiently to cause problems
given a couple month shelf life, keeping the eggs safe to eat so long as they are cooked. Even for those eggs not internally contaminated
with salmonella, it’s still best to keep them refrigerated if they have previously
been. As scientific adviser to the International
Egg Commission Vincent Guyonnet notes, “Once you start refrigeration, you have to have
it through the whole value chain, from farm to store. Because if you stop — if the eggs are cold
and you put them in a warm environment — they’re going to start sweating.” The United Egg Producers Association further
notes that condensation on egg shells “facilitates the growth of bacteria that could contaminate
the egg.” So why aren’t Europeans and others who don’t
refrigerate their eggs getting food poisoning left and right from eating contaminated eggs? They rely on other methods to keep the salmonella
problem in check and don’t refrigerate them at any point, though because of the sweating
and contraction issues with significant temperature changes, they do recommend eggs be stored
in transport and by supermarkets at specific temperatures- in the winter between 66.2 – 69.8
degrees Fahrenheit (19 – 21 degrees Celsius) and in the summer between 69.8 – 73.4 degrees
Fahrenheit (21 – 23 degrees Celsius). For starters, the European Union prohibits
egg producers from washing their eggs. You see, shells have natural protection from
salmonella and other contaminants via a waxy substance known as the cuticle. The cuticle coats the shell initially as a
liquid when a hen lays the egg and then dries within minutes of being exposed to the air. Egg washing, when done properly, may eliminate
surface contaminants, but it also washes away the cuticle and its natural protection, potentially
allowing bacteria to get into the egg via its pores or hairline cracks. Both methods of eliminating external contaminants
are quite effective, but the washing strategy requires that the eggs are processed in a
very precise way to be effective. If, for instance, eggs are allowed to sit
in dirty washing water too long after losing the cuticle, this would be an ideal situation
for microbes to quickly infect the inside of the eggs. Thus, the EU and others deem it safer to cut
out the potentially error-prone middle man and simply leave the cuticle on. Of course, by not washing the eggs at all,
the occasional egg with feces and other such things will pop up (the egg being laid via
the same hole the chicken poops through and the laying area potentially not being perfectly
clean). But the fact that visibly dirty eggs will
most definitely turn off some customers and that European Union egg farmers aren’t allowed
to wash the eggs is actually seen as a net-positive by some. For instance, Britain’s Egg Industry Council’s
Chief Executive Mark Williams states of this, “In Europe, the understanding is that [prohibiting
the washing and cleaning of eggs] actually encourages good husbandry on farms. It’s in the farmer’s best interests then
to produce the cleanest eggs possible, as no one is going to buy their eggs if they’re
dirty.” Unfortunately, in this scenario you’ll still
get the occasional egg with fecal matter or the like on it. This also increases the chances of cross contamination
with handling the potentially contaminated egg shells and then perhaps touching other
food items without washing your hands. But both of these problems are easily solved
by simply washing the eggs (and your hands) directly before using them. This “do nothing” method also saves an
amazing amount of effort and cost in the processing of the eggs. It’s also a superior method of keeping eggs
as safe as possible in areas where end customers don’t necessarily have refrigerators, as
well as helps minimize the risk of egg contamination if a customer has a long drive home from the
supermarket, which potentially allows the cold egg shells to form condensation giving
pathogens easier access to the inside. So, the cuticle solves the problem of external
sources contaminating the inside of the egg, but how does the EU and other countries that
don’t refrigerate their eggs deal with eggs that were contaminated while being formed
inside the chicken? They mandate that their egg laying chickens
must be vaccinated against salmonella, among other requirements, if they are to receive
the Lion Quality Code of Practice seal. The result of this is that approximately 90%
of chicken eggs sold in Britain come from vaccinated hens, with the other 10% coming
from small farmers who don’t typically sell eggs through major retailers. So which way of storing eggs produces fewer
cases of salmonella induced food poisoning? As the aforementioned Vincent Guyonnet notes:
“They’re different approaches to basically achieve the same result… We don’t have massive [food safety] issues
on either side of the Atlantic. Both methods seem to work.” But what about the numbers? In that, there seems to have never been any
definitive studies (at least that I could find), but it would seem on the surface that
the European method is the winner. (Though there are uncontrolled factors that
could potentially be skewing the numbers, so take this with a very large grain of salt.) On average, there are approximately 142,000
cases of egg-related salmonella poisoning in the United States every year according
to the U.S. Department of Agriculture. This is approximately 1 in 2,200 people infected
every year (give or take depending on whether an individual is a repeat offender in a given
year). In contrast, in England and Wales in 2009,
there were just 581 cases of egg-related salmonella poisoning, or about 1 in 95,000. Notably, before the British started vaccinating
their chickens in the late 1990s in response to a major egg-induced salmonella outbreak,
in 1997 there were 14,771 cases of egg related salmonella poisoning in England and Wales,
or 1 in 3,700. You might then be wondering why it simply
isn’t mandated that United States egg producers vaccinate their chickens. This is primarily because when the last batch
of rules concerning this very thing were put together, the limited number of large sample-size
studies available indicated vaccination wasn’t an effective way to stop the internal contamination
of salmonella in eggs. More recent vaccination methods and studies
have produced entirely different results. Because of this, and the fact that henhouses
and eggs are now being continually tested for salmonella contamination (with a positive
result meaning the egg farmer must break all the eggs open from a batch and pasteurize
them, leading to significant profit loss), approximately one-third to one-half of all
egg producers in the United States have voluntarily begun vaccinating their chickens. This voluntary adoption of vaccinations was
also spurred on in response to a 2010 egg-related salmonella poisoning outbreak in the United
States resulting in half a billion eggs needing recalled. To avoid such problems, more and more U.S.
egg farmers are jumping on board the hen vaccination train every year. In the end, while there are pros and cons
of each method of keeping eggs contaminate free, both have proven extremely effective
when properly executed, though seemingly the European method has a large edge in terms
of keeping people from getting sick. However, if you’ve got a refrigerator handy,
it is superior in one regard- eggs that are not refrigerated have a shelf life of about
three weeks. Those stored in a typical consumer’s refrigerator
are generally good for about two months, and drastically longer given better regulated
temperatures, something that used to be key to keeping eggs on the supermarket shelves
year round. You see, naturally most chickens will stop
laying eggs in the winter as a response to shorter daylight hours. (There is a photo-receptive gland in a chicken’s
eye that, when exposed to sufficient light, ultimately triggers the release of the hormone
that in turn spurs egg production when present in sufficient quantities in the hen.) This created an egg supply problem that used
to be solved by egg farmers in the United States via keeping the eggs at the perfect,
constant chilled temperature not found in your normal consumer refrigerator which is
regularly being opened and closed. This allowed egg producers to store eggs for
as much as a year according to United Egg Producers’ Vice President of Government
Relations, Howard Magwire. Today, of course, the problem is somewhat
controversially solved with artificial light and strictly controlled egg production environments
with the egg finding its way from hen to customer generally in under a couple weeks, regardless
of what time of year it is. Bonus Fact:
Ever wonder what the difference between brown eggs and white eggs are? Well, wonder no more. While some people say that brown eggs are
better for you and contain more nutrients; or that brown eggs taste better; or brown
eggs are better for cooking things like quiches, while white eggs are better for baking cakes,
etc. etc., the truth is the difference between brown eggs and white eggs are that brown eggs
are brown and white eggs are white. How the rumours started about brown eggs being
“better” is thought to be because they are often more expensive at supermarkets. This is, in part, because the hens that lay
them usually eat more, which means the hens cost more to keep per egg. You see, white eggs are most often laid by
white or light coloured hens with white ear lobes, while brown eggs are most often laid
by red-feathered or brown / dark-feathered chickens with red ear lobes. (This is not a universal truth, just a general
rule. Further, the chicken's ear lobes are really
the indicator here, not the feathers, but there is a very strong correlation between
ear lobe colour and feather colour, so feather colour can be a decent indicator too. Ultimately, egg colour is determined by genetics,
but the ear-lobe / feather colour thing is a good, though slightly flawed indicator.) In the end, red-lobed chickens tend to be
larger than their white-lobed counterparts, which is why they eat more. The farmers need to get reimbursed for the
extra feed somehow, so they up the price of the brown eggs. This also explains why white eggs tend to
be more popular in supermarkets. White-lobed chickens cost less for farmers
to keep, which leads to cheaper eggs, which leads to grocers buying more white eggs to
put on the shelves to offer this product cheaper to customers. White eggs are simply more cost-effective. As for the supposed difference in taste and
nutritional content, there isn’t one, with one caveat, though it isn’t anything to
do with the colour of the egg—rather, it has to do with the chicken’s diet. Many chickens raised at home are brown-egg
layers, while most of the chickens raised for commercial use are white-egg layers. The different diets affect the taste of the
eggs and even the colour of the yolk, similar to how diet can drastically affect the taste
of the meat of some animal. However, if you were to take one of those
brown egg-laying chickens and raise it on the same food as a white egg laying chicken,
their eggs would taste the same and be otherwise indistinguishable aside from the colour of
the shell. If their diets are the same, the yolks will
even be identical in colour. Today, chickens raised for commercial purposes,
whether layers of white eggs or brown, are all getting fed the same thing, with perhaps
just a slight variance from company to company. If you've had some brown eggs from a neighbor
or a chicken of your own that's fed a different diet than commercially fed chickens eat, then
there may be a difference in taste. It just doesn't have anything to do with the
colour of the egg. Of course, these days some of the most hotly
debated arguments aren’t over white vs. brown eggs, but over the superior quality
of organic vs. not organic eggs, or free range vs. cage eggs. While differences in diet can affect the taste,
if you're wondering about quality of the egg or nutritional value, a study done by D.R.
Jones et al. through the Agricultural Research Service and published in Poultry Science in
2010 found that, ultimately, there is very little difference in the quality of eggs produced
in these different ways. The small differences they did find "varied
without one egg type consistently maintaining the highest or lowest values."
This guy's voice is completely hypnotizing to me for some reason. Very interesting video!
I've lived in Sweden where eggs are kept in the fridge too, even though they technically don't need to. That usually means that eggs last much longer than their expiration date since that is set by EU standards that assume that eggs are not stored cold.
I'm currently in Austria where they sell already boiled eggs in most stores that are both non-refrigerated and often have their shells dyed. Now that's weird!
A chicken will sit on eggs for days if you let them, and they are still good to eat.
I was wondering about that. Thank you for sharing!
When I was living in Spain and saw eggs just sitting out in the super market, I wasn't worried they would go bad (figured the store knew what they were doing), but thought "wtf are we doing this in the States?!" Lol
Love me some Simon Whistler. He looks like the British Vsauce!
I raise chickens, and in relevant the forums, new chicken owners are forever asking, "Should I refrigerate or not?" so I chuckled a bit when Grey talked about his eggs, knowing there'd have to be a post about it in the reddit.
I'm glad the video mentioned EU chicken vaccinations. It's one of those "not technically required but you really want this seal of approval so yeah kind of of required" sorts of rules.