The MOF&G Online
MOFGA Technical Advice
by Diane Schivera
Many natural barriers help prevent bacteria from entering eggs. The "bloom" or "cuticle," a gelatinous covering that dries after the egg emerges from the hen, helps seal the pores in the shell, reducing moisture loss and bacterial penetration. The many egg membranes also help prevent the passage of bacteria. The shell membranes contain lysozyme, a substance that helps prevent bacterial infection. The egg white discourages bacterial growth because it is alkaline and binds nutrients in a form that bacteria can’t use, and the thick white discourages the movement of bacteria. As the egg ages, the white thins and the yolk membrane weakens, enabling bacteria to reach the nutrient-dense yolk, where they can grow over time if the egg is kept warm. In a clean, fresh shell egg, internal contamination rarely occurs.
Care in the hen house helps to produce healthy eggs. Have one nest box for every four to five hens. Keep the bedding clean and deep. Collect eggs often and at least twice a day in the winter to prevent freezing. Don’t stack eggs more than five layers deep when carrying them.
Some customers want unwashed eggs that are protected by the natural factors mentioned above. The quality of unrefrigerated eggs will decrease faster than refrigerated eggs, as the white gets thinner faster, but if refrigeration is not possible, these naturally protected eggs will keep well for many weeks or months. If you want to produce unwashed eggs, use sandpaper to remove small bits of dirt.
If you prefer to wash eggs, use water that is 20 degrees warmer than the egg and is at least 90 degrees F.; this will make the egg contents swell and push dirt away from the pores of the egg. If you have extremely dirty eggs, a mild detergent or sanitizer (1/2 oz. chlorine to 1 gal. of water) approved for washing eggs can be used. Never let eggs sit in water, and don’t even submerge them; just have them in a colander and slosh them in the cleaner. Otherwise, once the temperature equalizes, the egg can absorb contaminants from the water. Cool and dry eggs quickly after washing, then store them, large end up, at 45 degrees F. and at 75% relative humidity. Eggs sitting at room temperature can drop as much as one grade per day.
If eggs are stored properly in their own carton or other stable environment, they should hold a quality of Grade A for at least four weeks. Store eggs small end down in an egg carton to keep the air cell (the pocket of air inside the egg) stable, which should decrease breakdown of the egg white and decrease the possibility of contamination.
You can have your birds tested for salmonella by contacting the State Veterinarian, Don Hoenig, at Donald.E.Hoenig@maine.gov or 287-3871.
The Maine Department of Agriculture requires that eggs offered for retail sale be labeled with:
If you pack in used cartons, Maine requires that you obliterate any USDA shield; obliterate grade declarations and replace with "B," then affix your label.
Grades are determined by candling to measure the air cell and determine the quality of the white and yoke, besides the cleanliness and shell quality. A Grade A egg is clean, unbroken, practically normal with an air cell less than 3/16 inch, has unlimited movement of the yoke within the white and is "free or bubbly," i.e., the white is not bound to the egg shell and can look bubbly when the egg is candled. The white must be clear and reasonably firm, the yolk free from defects. The Maine Department of Agriculture recommends that folks who cannot candle their eggs should label their eggs grade B, which includes all but the worst eggs. If you can candle your eggs, explicit rules dictate what is allowed for each grade. The information is available from the USDA at www.usda.gov/, from the Maine Dept. of Agriculture at 287-3871 or www.maine.gov/cgi-bin/htsearch?config=state&words=egg+regulations, or by mail from me.
Weight classes are: Small--1.4 oz./egg and 18.2 oz./dozen; Medium--1.7 and 21.3; Large--1.9 and 24.3; Extra-large-- 2.2 and 27.3; and Jumbo-- 2.5 and 30.4.
Another way to grade eggs according to USDA regulations is called "U.S. Nest Run % AA Quality," which "shall consist of eggs of current production of which at least 20 percent are AA quality; and the actual percentage of AA quality eggs shall be stated in the grade name. Within the maximum of 15 percent which may be below A quality, not more than 10 percent may be B quality for shell shape, pronounced ridges or thin spots, interior quality (including meat or blood spots), or due to rusty or blackish-appearing cage marks or blood stains, not more than 5 percent may have adhering dirt or foreign material on the shell 1/2 inch or larger in diameter, not more than 6 percent may be Checks [cracks], and not more than 3 percent may be Loss [losses from checks, dirt, etc.]. Marks which are slightly gray in appearance and adhering dirt or foreign material on the shell less than 1/2 inch in diameter are not considered quality factors. The eggs shall be officially graded for all other quality factors. No case may contain less than 75 percent A quality and AA quality eggs in any combination." The weight classes for Nest Run % AA Quality are: XL-- 1.7lb./doz., 2.2 oz. each; 1--1.6 lbs. and 2.1 oz.; 2--1.5 lbs. and 2 oz.; 3--1.4 lbs. and1.9 oz.; 4--1.3 lbs. and 1.8 ounces. [From http://amsdev.ams.usda.gov/poultry/pdfs/EggGrading%20manual.pdf&text]
Restricted eggs and cracked, dirty, leakers, or incubator rejects can be sold only directly to the consumers. They must be labeled as Restricted.
Fresh eggs must be fewer than 30 days old; older eggs must be labeled as "Storage Eggs." Eggs that have been treated to inhibit natural deterioration must be labeled "Processed." The terms "fresh eggs," "strictly fresh eggs," "hennery eggs," "new-laid eggs," "farm fresh eggs," "selected eggs," "quality certified eggs," "nearby eggs," "native eggs" or words or descriptions of similar import shall not be used on any eggs that do not meet the minimum requirements for Maine consumer Grade A.
Blood or meat spots are found occasionally on an egg yolk and merely reflect either the genetics or age of the hen. They occur when a blood vessel ruptures on the yolk surface when it’s being formed or by a similar accident in the wall of the oviduct.
Care of Eggs for Hatching
DO NOT wash eggs unless necessary. Store the clean, fertile eggs in an area that is kept at 55° to 60° F. and at 70 to 75% humidity, never at temperatures above 75° F. or at lower than 40% humidity. Store the eggs small end down and slanted at 30 to 45 degrees, and turn them daily. Putting a 2" x 4" under one end of the carton or storage container and moving it to the other end daily works well.
Do not store eggs for more than 10 to 14 days, since hatchability begins to decline significantly after 14 days. Just before setting eggs under a hen or in the incubator, let the eggs warm to room temperature (70 to 80° F.) and remove any cracked eggs.
Some Natural Egg Colors
If you want to use some natural pigments to color eggs, at Easter, for example, you can use the following dyes on hard boiled eggs or on raw eggs that are not going to be eaten (since submerging raw eggs in dye may force pathogens into the egg). These pigments work best on white or light eggs.
Yellow: To a cup of hot water, add 1 to 1 1/2 teaspoons of turmeric and 1/2 teaspoon vinegar.
Golden Tan: Save the skins from yellow onions. Add them to the water when you hardboil your eggs.
Brown: To a cup of hot water, add 1 Tablespoon of instant coffee and 1/2 teaspoon vinegar.
Green: Soak your eggs in liquid chlorophyll (available from pet stores or drug stores).
Pretty Pastels: Rub blueberries and cranberries on the shells for soft blues and pink. Blend them for another pretty result.
For more information, see:
Dr. Michael Opitz’s Poultry Fact Sheet, University of Maine Cooperative Extension. firstname.lastname@example.org
"Care of Hatching Eggs," Small Flock Factsheet Number 8, Phillip J. Clauer, Poultry Extension Specialist, Animal & Poultry Sciences Department, Virginia Tech Univ., www.ext.vt.edu/index.html
Incredible Egg Web site, www.aeb.org
Rosie's Easter Basket, Rosemary (Rosie) Winters, www.night.net/easter/eggcolor.html-ssi (information on dyeing eggs)
About the author: Diane Schivera is Assistant Director of Agricultural Services for MOFGA...as well as our resident eggspert! You can contact her at 207-568-4142 or at email@example.com.
Winter is the time to plan gardening and farming practices that will overcome problems from the past year. It is a time of optimism. Looking forward to great success is easy with all the beautiful pictures in seed catalogs, but the rotting vegetables in the root cellar may bring back a handful of bad memories. The damp, cool summer of 2004 is mostly forgotten now, but crops that were not worth harvesting or those that spoiled downstairs are repercussions of that fungus-favoring growing season.
Crops in the onion family were particularly hard hit last summer. If your bad memories include blue, fuzzy garlic or soft, squashy onions, you may want to read on to understand causes and possible solutions for the next growing season.
Organic growers lean on cultural practices to avoid or control these problems. A growing system has to be set up in order for these practices to work, and since you are really trying to eliminate pests or hide your crops from them, your neighbors’ activities may have to be included in your concerns.
Sanitation is key, but organic farmers always have to balance adding crop residue for organic matter versus getting rid of crop residue because it harbors pests. Knowing which disease problem you have and the life cycle of the organism that causes it is the starting point. Don’t destroy valuable organic matter if crop debris is not the major source of disease spores. For example, spores of gray mold blow in almost any summer wind. But if a disease overwinters in a very limited crop, then destroying that debris will go a long way to solving the problem. For example, late blight overwinters here only in potatoes.
Crop rotation is the most rewarding cultural practice on an organic farm. It is used with green manures to add organic matter, manage nutrients, control weeds and to control insects and diseases. But the biology of the pest is a key factor in the effectiveness of rotation, and if you have a single, small garden, then crop rotation is great for most of these benefits but really will not work for insect and disease control.
Factors that must be considered as you consider crop rotation are:
Host specificity--If a particular disease is limited to a single species or even a single family of crops, then rotation has great potential to help you avoid the problem. An example is early blight in tomatoes. But if the disease affects a wide variety of crops and weeds, then spores are likely to be unavoidable. Examples include white mold of beans, carrots, tomatoes, peppers and many species.
Persistence--If the pest (such as Colorado potato beetle) can persist only a short time without a host, then you have a great opportunity to get rid of it quickly. But if the problem can hang around year after year in one form or another and wait for you to try again, then crop rotation is unlikely to really help. Black scurf on potatoes is an example.
Ability to disperse--Some insects (such as the potato leaf hopper) and spores blow in from hundreds of miles away, and the location of your crop makes no difference. Other problems, such as gummy stem blight of cucurbits, may have only limited ability to spread or spread only at limited times and conditions, so crop rotation has real potential.
Management ability is often said to replace chemical inputs for organic growers. To use cultural practices effectively, you have to pay attention to all the factors that you can control. Figure out what the problem is, learn the biology of the organism and decide how to avoid or destroy it in your system.
Now, back to last year’s onion and garlic crops. Problems started early with onion maggots, and by midseason I saw Botrytis leaf blight all over the state. Many of us finished with blue mold on garlic and rotting onions.
Onion maggots are the larvae of a fly (Delia antiqua) that flies around early in the spring and lays eggs at the base of the plant. The maggots crawl down and feed on the roots. On larger onions, maggots may stunt growth, cause yellowed leaves and misshapen onions. When they attack very young seedlings, the plants wilt and simply disappear. If you dont go out to your field for a few days, you may miss seeing the wilt stage and may just wonder what happened to your onion seedlings.
Onion maggots overwinter as pupae in the soil. A big pile of rotting onions from a cleaned out root cellar can attract the flies from all over; they breed and lay eggs in the soil in late summer, then you have a huge population of overwintering pupae...I know from experience. In the spring the pupae develop and flies emerge to hunt for your new onion seedlings.
Sanitation is key. Do not leave a bunch of old cull onions lying around in the summer and fall, and get any that are not worth harvesting out of the field. If you think you may have a big problem, a floating row cover can exclude the early spring population.
Botrytis leaf blight (Botrytis squamosa), under prolonged moist conditions such as those of last summer, can take down whole fields of onions, with most leaves dying. It starts as discrete, circular to oval, grayish to white leaf spots. The disease results in a greatly reduced harvest of small bulbs.
The fungus overwinters as sclerotia (hardened, dormant pieces of fungal mycelia that can resume growth under favorable conditions) on crop debris, on unharvested onions and in onion cull piles. The sclerotia germinate in the spring, then released spores are carried by wind over relatively long distances to onion leaves. Given sufficient moisture for long enough time on leaves, the spores germinate and the disease cycle begins again.
Regular rotation will prevent sclerotia from building up in the soil, where they can persist for two years. Cull onions should be eliminated, and leaf debris should be plowed deeply to bury sclerotia. Rotation will work only if your fields are isolated from your old fields and from those of neighbors with the problem. The best nonchemical solution is nice dry weather and managing overhead irrigation to avoid prolonged leaf wetness.
Rotting onions were common last fall for two reasons: Botrytis neck rot and sour skin. Sour skin is a disease caused by bacteria (Pseudomonas cepacia), and Botrytis neck rot is caused by the fungus Botrytis. These rots are common in onions after harvest and going into storage. Sour skin begins in the field with one or two leaves turning yellow to brown. After harvest or in storage, a few outer bulb scales turn yellow and soft. These diseased scales can be separated easily from the healthy ones. With neck rot the disease is first seen as rotting scales in the neck area, then it advances down toward the base.
Sclerotia from cull onions are the primary source of neck rot infection. It is also seedborne. In wet weather plants are infected by airborne spores from other infected plants. Infection can also occur during harvest if bulbs are damaged. Neck rot control is based on sanitation, e.g., eliminate cull piles, bury debris deeply, and rotate out of the onion family for at least two years. Onions with thick necks should be avoided for storage. Home gardeners can use these onions as soon as possible, or peel, chop and freeze them. Storage onions should be cured until they are thoroughly dry before being put into storage, and the storage area should be just above freezing and dry.
Sour skin is also more common in wet years or with prolonged wetness from overhead irrigation. Avoid damage during harvest, and although heat during curing may at first encourage the disease, it should be used if necessary for proper curing.
Blue mold of garlic (Penicillium sp.) is usually seen at harvest and in storage as a blue to green fungal growth on the surface. The first symptoms are pale yellowish blemishes that become watery soft spots. Again, this pathogen does best under moist conditions. The avenue of infection usually is damage at planting or wounding cloves during harvest. Handle cloves with care and avoid planting infected cloves. Rotation is unlikely to be of any value, because Penicillium is common on debris in soil.
About the author: Eric is MOFGA’s director of technical services. You can contact him at firstname.lastname@example.org or at 946-4402 with your questions about crop growth.
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