Why no washing/disinfecting eggs?

[theredroosta]

Quote:
Several things wrong in this argument.

You can't keep a domestic bird unnaturally, we created it. The way the domestic fowl has been living is natural.
How would you know what the hen would do in it's habitat? The behaviors of the wild fowl are purely based on instinct and genetics, nothing more. Just like a bird instinctively knows to flap its wings when it falls or jumps to break its fall even if it cannot fly. And this instinct is found in wild fowl only, jungle-fowl. Wild fowl would not have near the amount of cleanliness that domestic fowl do. Wild fowl would nest on the ground, in feces, in high trees where the eggs would drop. Saying that wild eggs would be untouched by bacteria is like saying that a toilet brush is devoid of foulness and is suitable to brush your teeth with. In a backyard flock, nesting sites are provided with clean bedding and enough so that hens do not have to fight or share. Rarely will a hen soil her eggs while laying them. Most problems caused by dirty eggs could be avoided by having clean nest boxes.

 

[BlacksheepCardigans]

Quote:
Sure - before I post the studies, let me say that my signature refers to the fact that before this summer I hadn't had poultry for about eight years. Before that I had birds ranging from cockatiels to cayugas every year of my life since I was two. I grew up across the road from a prominent pheasant and waterfowl fancier, figured that everybody had black-necked swans in their backyard. I've personally raised and bred chickens (LF and bantam), ducks (runner and cayuga), geese (Pilgrim and African), guineas, house birds of all types, etc. I don't show poultry, because I have no way to quarantine, but I have shown rabbits, Saanens, horses, and now dogs. I have a biology degree and was the teaching assistant who ran the embryology lab (based on chicken eggs and embryos). 90% of a theology master's, too, though that's not necessarily apropos to the discussion

. So no, I'm not new to this.

Here are the studies:

http://edis.ifas.ufl.edu/ps018 is a very good overview of the reasons for disinfecting
http://www.ncbi.nlm.nih.gov/pubmed/1906612 - using hydrogen peroxide; note that dead embryos were significantly reduced when compared to unwashed eggs
http://www.ncbi.nlm.nih.gov/pubmed/2356172 - using quat; again notice that hatchability is improved over untreated
http://www.ncbi.nlm.nih.gov/pubmed/2196048 - the fact that even touching dry litter contaminated with salmonella contaminates the egg in 60% of UNWASHED eggs; if the eggs have moist contamination (as in touching feces), the rate is 100%
http://www.jstor.org/pss/1592082 - chicks hatching from eggs with salmonella quickly infect the other chicks in the same brooder
http://japr.fass.org/cgi/content/abstract/8/4/499 - bacteria easily penetrate egg shells - note "the natural defenses of the egg are generally not adequate" http://japr.fass.org/cgi/reprint/8/4/499.pdf is the full-text PDF of the same article, and is critical to read through; note that by the time the egg has dried in the nest, whatever it was sitting in has been drawn through the pores already.
http://japr.fass.org/cgi/reprint/3/3/234.pdf - e. coli on hatching eggs; disinfection will improve hatchability
There's a great study by Sparks (1985) called "Bacterial penetration of the recently oviposited shell of hens' eggs" showing that the riskiest time was right after the egg was laid, while it was cooling

And before anybody says that backyard flocks don't have to worry about salmonella, yes they do. Salmonella is everywhere - got chickens? You've got a very high chance of having salmonella bacteria out there. http://www.jstor.org/pss/1592033 is a study that isn't easily available in full-text, but they tested a bunch of flocks and found that 100% of their positive s. pullorum results came from backyard flocks. The commercial flocks also had salmonella, of course, but the backyard birds were far from sterile.

I have, seriously, about a hundred more, but the above are some of the most useful and direct.

 

[Muggsmagee]

Quote:
Sure - before I post the studies, let me say that my signature refers to the fact that before this summer I hadn't had poultry for about eight years. Before that I had birds ranging from cockatiels to cayugas every year of my life since I was two. I grew up across the road from a prominent pheasant and waterfowl fancier, figured that everybody had black-necked swans in their backyard. I've personally raised and bred chickens (LF and bantam), ducks (runner and cayuga), geese (Pilgrim and African), guineas, house birds of all types, etc. I don't show poultry, because I have no way to quarantine, but I have shown rabbits, Saanens, horses, and now dogs. I have a biology degree and was the teaching assistant who ran the embryology lab (based on chicken eggs and embryos). 90% of a theology master's, too, though that's not necessarily apropos to the discussion

. So no, I'm not new to this.

Here are the studies:

http://edis.ifas.ufl.edu/ps018 is a very good overview of the reasons for disinfecting
http://www.ncbi.nlm.nih.gov/pubmed/1906612 - using hydrogen peroxide; note that dead embryos were significantly reduced when compared to unwashed eggs
http://www.ncbi.nlm.nih.gov/pubmed/2356172 - using quat; again notice that hatchability is improved over untreated
http://www.ncbi.nlm.nih.gov/pubmed/2196048 - the fact that even touching dry litter contaminated with salmonella contaminates the egg in 60% of UNWASHED eggs; if the eggs have moist contamination (as in touching feces), the rate is 100%
http://www.jstor.org/pss/1592082 - chicks hatching from eggs with salmonella quickly infect the other chicks in the same brooder
http://japr.fass.org/cgi/content/abstract/8/4/499 - bacteria easily penetrate egg shells - note "the natural defenses of the egg are generally not adequate" http://japr.fass.org/cgi/reprint/8/4/499.pdf is the full-text PDF of the same article, and is critical to read through; note that by the time the egg has dried in the nest, whatever it was sitting in has been drawn through the pores already.
http://japr.fass.org/cgi/reprint/3/3/234.pdf - e. coli on hatching eggs; disinfection will improve hatchability
There's a great study by Sparks (1985) called "Bacterial penetration of the recently oviposited shell of hens' eggs" showing that the riskiest time was right after the egg was laid, while it was cooling

And before anybody says that backyard flocks don't have to worry about salmonella, yes they do. Salmonella is everywhere - got chickens? You've got a very high chance of having salmonella bacteria out there. http://www.jstor.org/pss/1592033 is a study that isn't easily available in full-text, but they tested a bunch of flocks and found that 100% of their positive s. pullorum results came from backyard flocks. The commercial flocks also had salmonella, of course, but the backyard birds were far from sterile.

I have, seriously, about a hundred more, but the above are some of the most useful and direct.

I'll come back to edit some more info in...I'll take this one at a time...starting with the last study.

http://www.jstor.org/pss/1592033 ...The pullorum test was taken "because of a recent outbreak of pullorum in an integrated broiler system". Does that not spell out "commercial operation"? I couldn't find anything on backyard flocks. Also, I'd like to mention that this test was conducted from 1989 to 1991. Seems the study is a bit old...does it still hold water today?

http://japr.fass.org/cgi/reprint/8/4/499.pdf ...This is a study created by the USDA FOR researchers and HATCHERY managers (aka commercial hatcheries). I did read where it mentioned "When an egg is laid, it is warmer than the environment, since the body temperature of the hen is 42°C. The warm egg cools to environmental temperature, and this cooling causes the contents of the egg to contract. Such contraction tends to form a negative pressure within the egg. Bacteria present in the environment or on the egg surface can then be pulled into and through the eggshell and its membranes." This pertains to every chicken.
"found that eggs are penetrated almost immediately when challenged with moist Salmonella-contaminated chicken feces"...so this clearly states the poo has to be infected w/ Salmonella, aka the chicken herself.
"In a field survey, Smeltzer et al. found that eggs laid on the dirty chicken house floor were more likely to exhibit internal bacterial contamination than were eggs laid in a nest box [8]. Eggs are most vulnerable to bacterial penetration in the first 30 to 60 sec after lay before the cuticle hardens and effectively caps the pores".

In this same article it talks about the eggs defense against bacterial invasion..."PHYSICAL DEFENSES The outermost physical defense that a bacterial cell encounters on an egg is the cuticle. The cuticle is a very effective barrier to water and carbon black particles [MI. Despite the fact that the cuticle allows gas passage, it seems to effectively fill the pores of the eggshell [Z]. However, this defense is not perfect. A small percentage of eggs are laid without cuticle; these eggs may easily be contaminated by water and carbon black [MI. Even when cuticle is present, for the first few minutes after lay it is an ineffective barrier to bacterial invasion until it hardens [19]. Nevertheless, the hardened cuticle is the major barrier to liquid and therefore is of utmost importance in bacterial exclusion. "
"Bains details the chain of Salmonella from breeder feed to the nest box, the hatchery, onto the grow-out farm, and to dressed carcasses. Broiler hatcheries have been shown to be reservoirs for Salmonella. In one study71%
of eggshell fragment samples were contaminated. In another study involving six commercial breeder hatcheries, 15.2% of the eggshell fragments were contaminated with salmonellae."

I'm looking for any mention of backyard (home) flocks. I will go through all of the articles/studies you found. Truly, it is fascinating. My apprehension when a study is done by the USDA, it usually has the big commercial farming business interest at heart. That doesn't mean we should apply their rules, NOR does it mean we should dismiss their findings. Also, I have yet to find ANYTHING that says you should or should not wash your eggs. Maybe I shouldn't go backwards. Bear with me.

the natural defenses of the egg are generally not adequate

that is only part of the study...THE EGG is porous, so no good defense...but we are talking about the bloom/cuticle, etc.
Okay...hold on...I'll be back.​

 

[kathyinmo]

Frankly, I appreciate this thread and the links. Honestly, I am going to give it a try. What can it hurt? Why all the challenges?

 

[BlacksheepCardigans]

Quote:
I know the full text of that last one is hard to find. The google-fu is strong within me and I can find fragments and chunks of the text - ordinarily I wouldn't rely on a study that I couldn't read in toto but in that case all I was looking for was salmonella in backyard flocks.

The quote is: "All of the birds with. S. pullorum were from backyard flocks." I think they found 18 infected flocks. That study wasn't for the purposes of finding out how many backyard flocks were infected; it was to identify the strains of salmonella that were out there. So it shouldn't be taken as a population study or a proportion study, just as evidence that salmonella is definitely present in backyard birds.

One of the big reasons that it's so hard to get rid of in backyard flocks, even if you buy from a salmonella-free breeder or hatchery, is thatit's present in songbirds . You're kind of SOL when it comes to preventing wild birds from ever pooping near your chickens.

 

[Muggsmagee]

Quote:
Fair enough question kathyinmo. I like a good debate. That is all. I like to hear both sides clearly, so would like to see a study from an unbiased point of view.

To the question of what can it hurt? Nothing. I can't find anywhere the CONCLUSIVE fact that washing/disinfecting vs. not washing is better. That's it. I just want to get to all the facts and the crux of the studies. And, quite frankly, I would love to partake in a controlled unbiased study. But that's the science geek in me talking!

 

[wilkey44]

I am removing so I dont get into any trouble

 

[Muggsmagee]

I'm not done with those studies...A.D.D. kicked in again.

Feel free to peruse this Mother Earth News article. http://www.motherearthnews.com/Natural-Health/2007-12-01/Bird-Flu-and-Factory-Farms.aspx

 

[mountainwhisper]

All of this information is incredibly interesting to me. I was wondering though if you want to try to disinfect the eggs with hydrogen peroxide, how do you do it? Do you dip them and dry them off, do you scrub them with it? What percentage hydrogen peroxide (Do you mix with water?) I am just curious as to the steps of the process.

 

[BlacksheepCardigans]

The way it's applied in all the studies is by spraying and then allowing to dry, so I think you could accomplish that best by dipping briefly and letting dry. You can use household hydrogen peroxide, which is 3%, and can dilute it up to 100% (i.e., to make a 1.5% solution) if desired. I found that concentrations from 1.5% to 5% were used in the research.

I think the closest thing to meeting the research with safety for the eggs and humans involved, using household materials only, is a brief hot-water wash (no soap), a dip in hydrogen peroxide, quick air dry, then into a clean and disinfected incubator. You'd do the whole hatch at once. The ideal is to keep the eggs warming up, not cooling down - every time it cools down it draws in stuff from the outside of the shell. I don't think any research has been done on how you accomplish any of it with eggs that have to be shipped or have to sit around, because in the commercial hatcheries they get eggs all in a big batch that are no more than a few days old. But I know the disinfection step happens at the hatchery, not at the breeder.