- Jul 10, 2015
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A lot of people seem to think that rinsing an egg with plain water will wash the protective bloom/cuticle off. I've always thought so too, but then a post on Instagram questioning this caught my attention and I decided to research it. Now I'm not so sure.
There are various studies researching washing eggs with various chemicals and detergents. I only found one that actually tested with plain water (albeit on quail eggs, not chicken eggs):
https://europepmc.org/article/med/32731973
Click to read the full text and look at Table 2. You'll see that water and sodium hypochlorite didn't seem to remove the cuticle. Both seemed to affect it slightly, with sodium hypochlorite having more of an effect, but neither removed it. All the other substances used did remove the cuticle.
Here's another study:
https://www.sciencedirect.com/science/article/pii/S0362028X22115528?via=ihub
In this one, eggs were washed with a mix of water and detergents. It didn't seem to affect the bloom/cuticle. This was their conclusion:
"We could find no evidence to suggest that the washing procedure used in this study irreversibly changed the cuticle quality of eggs from the end of lay, which inherently had poor cuticle coverage (worst-case scenario). This conclusion was valid for both brown and white eggs and was based on the assessment of the cuticle coverage, using a dye, and on the cuticle quality criteria as assessed by SEM. Moreover, within each group of eggs, a lot of variation in cuticle coverage and quality naturally occurred."
A third study:
https://www.sciencedirect.com/science/article/pii/S0032579119495928
This had a variety of findings:
1. Cuticles vary by hen. Some hens lay eggs with very little to no cuticle. Other hens lay eggs with a cuticle covering most, but not all of the egg.
2. Hen age didn't seem to make a difference. (Which was interesting, because the study I linked to first contradicted this.)
3. Brushing/scrubbing eggs can damage the cuticle.
4. The cuticle deteriorates naturally with age.
5. Spraying eggs with chlorine dioxide did not affect the cuticle.
6. Manure did affect the cuticle.
So, based on that, if you try to scrub dirt/poop particles off with a brush and without water, there's a chance you might be damaging the bloom more than if you washed the egg.
An article (not a study):
https://www.cfsph.iastate.edu/thelivestockproject/eggs-is-washing-and-refrigerating-necessary/
This says, "Using a chlorine-based sanitizer between 50-100ppm protects the cuticle of the egg while sanitizing." Not sure what their source is. It also says, "Warm water allows the egg to expand and push bacteria out, but cold water pulls the bacteria in."
Hatching & Brooding Your Own Chicks (Gail Damerow) says:
"You don't want to wash the eggs, for fear of removing the protective bloom, but you might dip them into a sanitizer. Some poultry keepers routinely sanitize all hatching eggs, which does not affect the bloom and does improve the hatch rate. . . . Never use water that's cooler than the eggs, because it can force contamination through the shell. Dip the eggs in the sanitizer for at least 1 minute but no more than 3 minutes, then set them on a clean towel to air dry; do not rub them dry, which would rub off the bloom."
What do you think? Is it a myth that washing eggs with water removes the bloom? Am I misunderstanding something? What if the protective quality of the bloom is compromised by water even if the bloom isn't removed? (Guess I could try to research that too.)
There are various studies researching washing eggs with various chemicals and detergents. I only found one that actually tested with plain water (albeit on quail eggs, not chicken eggs):
https://europepmc.org/article/med/32731973
Click to read the full text and look at Table 2. You'll see that water and sodium hypochlorite didn't seem to remove the cuticle. Both seemed to affect it slightly, with sodium hypochlorite having more of an effect, but neither removed it. All the other substances used did remove the cuticle.
Here's another study:
https://www.sciencedirect.com/science/article/pii/S0362028X22115528?via=ihub
In this one, eggs were washed with a mix of water and detergents. It didn't seem to affect the bloom/cuticle. This was their conclusion:
"We could find no evidence to suggest that the washing procedure used in this study irreversibly changed the cuticle quality of eggs from the end of lay, which inherently had poor cuticle coverage (worst-case scenario). This conclusion was valid for both brown and white eggs and was based on the assessment of the cuticle coverage, using a dye, and on the cuticle quality criteria as assessed by SEM. Moreover, within each group of eggs, a lot of variation in cuticle coverage and quality naturally occurred."
A third study:
https://www.sciencedirect.com/science/article/pii/S0032579119495928
This had a variety of findings:
1. Cuticles vary by hen. Some hens lay eggs with very little to no cuticle. Other hens lay eggs with a cuticle covering most, but not all of the egg.
2. Hen age didn't seem to make a difference. (Which was interesting, because the study I linked to first contradicted this.)
3. Brushing/scrubbing eggs can damage the cuticle.
4. The cuticle deteriorates naturally with age.
5. Spraying eggs with chlorine dioxide did not affect the cuticle.
6. Manure did affect the cuticle.
So, based on that, if you try to scrub dirt/poop particles off with a brush and without water, there's a chance you might be damaging the bloom more than if you washed the egg.
An article (not a study):
https://www.cfsph.iastate.edu/thelivestockproject/eggs-is-washing-and-refrigerating-necessary/
This says, "Using a chlorine-based sanitizer between 50-100ppm protects the cuticle of the egg while sanitizing." Not sure what their source is. It also says, "Warm water allows the egg to expand and push bacteria out, but cold water pulls the bacteria in."
Hatching & Brooding Your Own Chicks (Gail Damerow) says:
"You don't want to wash the eggs, for fear of removing the protective bloom, but you might dip them into a sanitizer. Some poultry keepers routinely sanitize all hatching eggs, which does not affect the bloom and does improve the hatch rate. . . . Never use water that's cooler than the eggs, because it can force contamination through the shell. Dip the eggs in the sanitizer for at least 1 minute but no more than 3 minutes, then set them on a clean towel to air dry; do not rub them dry, which would rub off the bloom."
What do you think? Is it a myth that washing eggs with water removes the bloom? Am I misunderstanding something? What if the protective quality of the bloom is compromised by water even if the bloom isn't removed? (Guess I could try to research that too.)
