Science, Art, Litt, Science based Art & Science Communication
Eggs - what science says about their spoilage and storage
It is not that easy to say what science says about storage and spoilage in a few words. because these things depend on several factors
In heat the eggs will decompose at a faster rate then normal, while in the winter the eggs can actually freeze and the shells become brittle and can crack or break.
In britain they usually don't refrigerate eggs. In the conditions pevelant in Europe and US, if you’ve washed them, you need to refrigerate (1).
You don’t need a lab, if that’s what you thought, your kitchen essentials are all that you need.
In the UK, it’s illegal to wash eggs before sale, because doing so removes a protective layer.
In the US, it illegal to NOT wash eggs before sale, because doing so also removes all the other stuff from the surface (1).
It is mandetory that eggs are washed and sprayed with a chemical sanitiser before they are sold in the US to reduce salmonella infection.
There are two ways that salmonella can infect eggs. The bacteria can be passed on from an infected hen, to the inside of the egg as it's developing or it can get onto the outside of the shell after the egg is laid by coming into contact with the hen's feces.
It is important that eggs are 'washed properly' so that the bacteria doesn't enter the egg through the shell. Wet surfaces provide more chances for contamination. Therefore, the washing solution has to be hot enough [ a minimum of 32.2 degrees C (90 degrees F)]. Immediately after washing they must be stored at lower temperatures of 7 .2 degrees C (45 degrees F) or lower. It must be maintained at that temperature till consumed. A cold egg left out at room temperature
can sweat, facilitating the growth of bacteria that could contaminate the egg.In Europe scientists have found that the washing process may damage an outside layer of the egg shell known as the cuticle. Without the chemical barrier, it might become easier for the bacteria enter the egg shell easily.
Moreover, as hens are vaccinated in Europe, salmonella contamination is not that big a problem in the Europe.
We have a different picture in very hot zones like India. During summer, the eggs will get spoiled whether you wash them or not if you keep them out for a long time. so we need to refrigerate them.
The shelf life of an unrefrigerated egg is 7 to 10 days and for refrigerated egg it’s about 30 to 45 days. Eggs can last for about 5-6 weeks if refrigerated properly.
A simple home test called Floating Test can be used to see whether an egg is spoiled or not. It’s the best way to tell the freshness of an egg without cracking it.
How Floating Test Is Done (2):
How Floating Test Is Done (2):
You don’t need a lab, if that’s what you thought, your kitchen essentials are all that you need.
-Fill a transparent bowl with cold water and place your eggs in it.
- If they sink to the bottom and lay flat on their sides, they are fresh and will make for a delicious omelet.
- If they stand on one end at the bottom of the bowl (in upright position) it means they are a few weeks old but still good to eat and as foodie Yumi Sakugawa tells the upright ones are perfect for hard-boiling.
- But if you find the eggs floating on the surface of the bowl, just know that they are no longer fresh enough to eat. Don’t toss them away just yet, put them to other uses (listed below).
Why Floating Test Is The Best Method ....
The reason this method works is because the eggshells are porous, which means they allow some air to get through. Which means the eggs that have been freshly laid will have less air in them, so they sink to the bottom. But the older eggs which have had more time for the air to penetrate the shells become more buoyant (light weight) and so it floats on the surface.
There Is Another Method To Test the Freshness (By Cracking Eggs)
It’s called the Plate & Sniff test. Unlike the floating test where the shell remains intact, P&S requires to:-
- Crack the egg onto a plate or any flat surface to check if it’s fresh or not.
- If it's fresh, the white shouldn’t spread much and the yolk should appear bright yellow/orange.
- Then give it a sniff: fresh eggs shouldn't have much of a smell. spoiled eggs smell horrible.
- If they sink to the bottom and lay flat on their sides, they are fresh and will make for a delicious omelet.
- If they stand on one end at the bottom of the bowl (in upright position) it means they are a few weeks old but still good to eat and as foodie Yumi Sakugawa tells the upright ones are perfect for hard-boiling.
- But if you find the eggs floating on the surface of the bowl, just know that they are no longer fresh enough to eat. Don’t toss them away just yet, put them to other uses (listed below).
Why Floating Test Is The Best Method ....
The reason this method works is because the eggshells are porous, which means they allow some air to get through. Which means the eggs that have been freshly laid will have less air in them, so they sink to the bottom. But the older eggs which have had more time for the air to penetrate the shells become more buoyant (light weight) and so it floats on the surface.
There Is Another Method To Test the Freshness (By Cracking Eggs)
It’s called the Plate & Sniff test. Unlike the floating test where the shell remains intact, P&S requires to:-
- Crack the egg onto a plate or any flat surface to check if it’s fresh or not.
- If it's fresh, the white shouldn’t spread much and the yolk should appear bright yellow/orange.
- Then give it a sniff: fresh eggs shouldn't have much of a smell. spoiled eggs smell horrible.
- If the egg is older, the white will be flowy and thin while the yolk will be flatter. But this does not necessarily imply the egg is bad for consumption. If it's gone really bad, you can right away make the distinction from the strong, distinct smell.
Footnotes:
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