Is it safe to eat raw egg whites? (3 risks)
In this article, we will discuss whether egg white is safe to eat raw, what are the risks related to eating egg whites raw, what happens when egg whites are cooked and how can you safely consume egg whites.
Egg whites are one of the most important sources of proteins in the human diet. However, the properties and safety of raw egg whites are not the same as those of cooked egg whites.
Is it safe to eat raw egg whites?
Yes, it is safe to eat raw egg whites when the whole shell egg or the egg whites have been pasteurised (1, 2). However, even though it is safe to eat, an excessive consumption of egg whites raw can be harmful to health (3).
There are three concerns about the consumption of raw egg whites: the risk of an infection by Salmonella or other pathogen, and the risk of biotin deficiency due to the overconsumption of avidin, a protein found in raw egg whites (1, 2, 3).
In addition, the presence of protease inhibitors, which are anti-nutritional factors may delay the digestive process (4).
What are the risks of eating raw egg whites?
The risks of eating raw egg whites are summarised in the table below (1, 2, 3, 4):
Salmonella infection or poisoning by its toxin
|The raw egg whites are contaminated with pathogenic bacteria Salmonella or the toxin it produces.||Contamination can occur by the infected hen, the poor handling of the shell eggs, improper pasteurisation of packaged egg whites or cross-contamination during preparation||Diarrhoea, vomiting, fever, abdominal pain and headache|
|Deficient body absorption of biotin, a water-soluble vitamin found in egg yolks, liver, whole cereals and some vegetables||Egg whites contain avidin, a protein. When consumed raw, avidin binds to the biotin, reducing its bioavailability and leading to biotin deficiency in humans||Weakened muscles, skin infections, hair and skin thinning, loss of muscle coordination, seizures, delay of development in children|
|Impaired or delayed digestion of proteins, due to the ingestion of protease inhibitors found in the raw egg whites||Raw egg whites contain four protease inhibitors, which reduce the activity of the enzymes pepsin, trypsin and chymotrypsin, which act in the digestion of proteins||Indigestion, possible hypersensitivity to eggs by children|
What happens when you cook the egg whites?
When you cook the egg whites, different chemical reactions and phenomena occur, which are summarised in the table below:
|Egg whites denaturation||Heat partially denatures the proteins, which unfold and assume a new structural configuration||Improvement of the digestibility and bioavailability of the proteins|
|Denaturation of avidin||Heat denatures avidin, the protein which can cause biotin deficiency||Improvement of the absoption of biotin from the diet|
|Denaturation of protease inhibitors||The protease inhibitors found in egg whites are inactivated to a great extent||Improvement of the digestive process of the ingested proteins|
|Destruction of bacteria||The microbial contamination is reduced by heat destruction||Improvement of the safety, reduction of the risk of infection by Salmonella or other pathogens|
Why should you cook the egg whites?
You should cook the egg whites to improve their safety and reduce the risk of having a biotin deficiency (1, 2, 3). In addition, the digestibility of egg whites is improved when cooked, favouring the bioavailability of the egg whites proteins (5).
When you cook eggs or egg whites, possible contamination of Salmonella and other pathogenic bacteria or their toxins is destroyed to an amount considered safe to consume (2).
Proteins in egg whites are considered of high quality due to the balanced and complete amino acid composition and high bioavailability. However, bioavailability is favoured when the egg whites are cooked, because of their better digestibility.
The digestibility of egg whites is improved from about 50 % to 90 % when egg whites are cooked, according to studies (5).
In addition, anti-nutrients are found in egg whites, which may impair the digestion of proteins (4). Cooking may inactivate these anti-nutrients.
How to safely consume raw egg whites?
To safely consume raw egg whites, you should choose pasteurised shell eggs or pasteurised packaged egg whites (1, 2, 6).
Shell eggs and liquid egg whites are industrially pasteurised under mild conditions to effectively reduce the microbial load, especially targeting the bacteria Salmonella, without affecting the physicochemical properties of the egg proteins.
In this way, commercial pasteurised egg products are considered safer to consume raw and have solubility, foamability and other functional properties preserved. However, all egg products are not safe to consume when improperly handled (2, 6).
To safely consume raw egg products, you should carefully inspect the products to notice any signs of spoilage, such as unpleasant off-odours and off-flavours, production of gas, exudation of liquids and discolouration (6).
In this article, we discussed the safety of eating raw egg whites, what are the possible risks of eating raw egg whites, and what happens when egg whites are cooked.
Egg whites are more nutritious and more flavourful when cooked, in addition to being safer to eat. Therefore, I recommend eating cooked eggs daily, as part of a healthy diet.
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