Is it a myth that water removes an egg's bloom?

[Ilovemychicks08]

I dont wash mine. I barely sell them and the people i do sell them to, dont care if there is a little dirt. Mine lay fairly clean eggs. But i dont think a little water would take away the bloom or the cuticle.

 

[quackingdom]

???

Scanning electron microscopy.

The studies I read only used staining if I remember right.

This is an interesting question; thanks for raising it. I haven't yet found anything pertinent to the main question, but in the meantime do note something I think important re: the cuticle/bloom, since those in the studies are surprisingly variable and of poor quality.

This paper https://doi.org/10.1016/j.psj.2021.101691 (Effects of genotype and age on eggshell cuticle coverage and color profile in modern laying hen strains, Poultry Science 2022) says age does matter, and genotype moreso. Given that the definition of 'old' hen in these modern studies is just over 1 year (55 or 60 weeks, 70 weeks), and all the hens used are commercial production types of one strain or another, currently I would be inclined not to generalize any results from these studies to backyard heritage breed hens free-ranging in a mixed habitat.

Hmm. What do you think would be different? Many people's backyard hens are more than a year old, so they might have less cuticle coverage. Would free-range hens tend to have better or worse cuticle coverage than a commercial production hen? More variability or less variability?

Egg color could make a difference as well. I believe one of these studies noted a difference between the cuticles of brown eggs and white eggs.

 

[TRALALARA1]

Interesting. I did something different this last hatch when I set the eggs. I took a warm damp paper towel and gently wiped off dried poop on the eggs. Just on the dirty ones which was quite a few. I was worried it could affect my hatch rate but I also didn’t want to introduce bacteria into the eggs by leaving the poop on. I had 27 of 30 eggs hatch and survive. Quite healthy actually. If we have much rain my hens can bring in a lot of mud on their feet and sometimes poop. I feel like wiping the eggs down had no effect on the chicks.

 

[Perris]

The studies I read only used staining if I remember right.

the 2011 paper you cited used SEM, not the 1975 one.

What do you think would be different? Many people's backyard hens are more than a year old, so they might have less cuticle coverage. Would free-range hens tend to have better or worse cuticle coverage than a commercial production hen? More variability or less variability?

Cuticle quality may decline with age, but I'm not going to generalise it to all hens on the basis of studies that used birds only 23-70 weeks old, who were all production hens, fed commercial feed, in confinement. One of my 5 years olds is laying stronger eggs now than she did when she was 1-2 years old.

I assume hens that are not restricted to commercial feed would have better cuticle coverage, because they get a diet that nourishes all of them, not just the bits required for maximum egg production at minimum cost. Free range hens get in addition fresh air, exercise, and probably a much better social life, all of which contribute to better health, I think. I imagine there is a lot of variability between them too; at least, I see a lot of variability in each single hen's eggs, depending on what she ate recently, and how good her health is.

 

[Yardmom]

When I think of washing an egg I think of scrubbing the dirt off and this clearly damaged the bloom coverage. May rethink how I wash eggs.

 

[aart]

I 'wash' eggs under warmer than the egg water and using my hands 'scrub' every part of the egg. I can feel the bloom, it feels kinda slimy. Some have much more than others, but pretty sure it all comes off. I only wash 'dirty' eggs immediately before using for myself,I do not wash eggs I sell.

 

[FunClucks]

I wash eggs to sell using the Mana Pro egg wash and a microfiber cloth and lots of warm water. The microfiber cloth gets all the bloom off.

I recently hatched some formerly dirty/muddy chicken eggs. I scrubbed them using a microfiber cloth while drenching them with hydrogen peroxide, then laid them on a paper towel to mostly air dry. All 24 developed, and 21/24 hatched. 20/24 were healthy chicks (one I culled due to a defect I think due to improper egg turning). I washed my hands before going into the brooder to turn or candle.

I don't know that washing with hydrogen peroxide helped increase my hatch rate, but it sure doesn't look like it hurt anything. The chicks were super healthy and have grown well.

 

[Perris]

What if the protective quality of the bloom is compromised by water even if the bloom isn't removed?

I don't think it is.

According to S. SAMIULLAH and J.R. ROBERTS 'The eggshell cuticle of the laying hen' World's Poultry Science Journal, Vol. 70, December 2014, the "cuticle layer of the eggshell is composed of inner calcified and outer non-calcified water insoluble layers" (emphasis added). This makes sense, as in nature an egg would be exposed to rain and dew, and if water in that form was harmful, the chick inside would fail to survive, so selection pressure must favour a cuticle not adversely impacted by exposure to rain. Another function of the cuticle is to keep "the water and electrolyte levels of the egg contents in balance by preventing evaporation", again suggesting impermeability.

They add that the cuticle is less effective as a microbial barrier when fresh and moist than when mature and dry, and that "Washing has the potential to damage the cuticle although manufacturers of modern egg washing equipment aim to reduce the impact on the cuticle".

Incidentally, noting the inconsistency in reports on the effect of age, they conclude that "Further research needs to be conducted to determine the effect of flock age on functional cuticle cover and such studies should involve vertical surveys of the same flocks at different ages". That was in 2014; I don't know if any more has been done on it yet.

 

[quackingdom]

I 'wash' eggs under warmer than the egg water and using my hands 'scrub' every part of the egg. I can feel the bloom, it feels kinda slimy. Some have much more than others, but pretty sure it all comes off. I only wash 'dirty' eggs immediately before using for myself,I do not wash eggs I sell.

If you dunked the eggs in water, then let them dry, then washed them again and scrubbed them with your hands, would you still feel the bloom?

I suppose, even if water doesn't remove the bloom, it's difficult to clean eggs without rubbing and scrubbing them, and there's not much point in just dunking them in water.

 

[quackingdom]

I don't think it is.

According to S. SAMIULLAH and J.R. ROBERTS 'The eggshell cuticle of the laying hen' World's Poultry Science Journal, Vol. 70, December 2014, the "cuticle layer of the eggshell is composed of inner calcified and outer non-calcified water insoluble layers" (emphasis added). This makes sense, as in nature an egg would be exposed to rain and dew, and if water in that form was harmful, the chick inside would fail to survive, so selection pressure must favour a cuticle not adversely impacted by exposure to rain. Another function of the cuticle is to keep "the water and electrolyte levels of the egg contents in balance by preventing evaporation", again suggesting impermeability.

They add that the cuticle is less effective as a microbial barrier when fresh and moist than when mature and dry, and that "Washing has the potential to damage the cuticle although manufacturers of modern egg washing equipment aim to reduce the impact on the cuticle".

Incidentally, noting the inconsistency in reports on the effect of age, they conclude that "Further research needs to be conducted to determine the effect of flock age on functional cuticle cover and such studies should involve vertical surveys of the same flocks at different ages". That was in 2014; I don't know if any more has been done on it yet.

Interesting.

I also found this...

https://www.petersime.com/hatchery-...-when-incubating-waterfowl-eggs-with-cuticle/

"Due to the increased degree of biological challenges experienced by the vulnerable embryo in its natural ‘wet’ environment, waterfowl eggs have a thicker ‘coating’ or cuticle compared to chicken eggs. This coating protects the eggs from contamination. In nature, the cuticle of waterfowl eggs gradually erodes during incubation due to the nest activity of the parent bird. This results in more exposed pores and, consequently, an increasing rate of gas exchange that provides the developing embryo with sufficient oxygen and creates an air cell big enough to facilitate hatching. To replicate the interaction between parent bird and incubating waterfowl eggs, two approaches are traditionally used. Some hatcheries actively remove the cuticle by washing the eggs before incubation. Others spray the eggs with water during incubation."