Whether you're a first-time poultry owner or have had birds for years, raising your own flock of laying hens for egg production can be a rewarding experience. Peak lay is in the summer, when the days are long, so if you want to preserve all those eggs for winter, make sure you do it safely, using approved methods. In this article we will explain how egg structure influences egg quality, how to wash eggs, one preservation method that is not recommended, and several that are recommended.
How Egg Structure Influences Quality
The United States Department of Agriculture's Egg-Grading Manual (2000) defines egg grades based on strict measurements and criteria, but in general here are some exterior and interior traits of high-quality eggs:
A high-quality exterior (eggshell) is
- free from cracks and thin spots,
- not misshapen,
- smooth and free from large or excessive calcium deposits, and
- clean/free from debris and stains.
Each of these exterior traits affects the shell's ability to be an effective barrier to prevent pathogens from entering the egg. In addition, the cuticle, sometimes referred to as "bloom", is an outer layer that provides protection by sealing the natural pores in the eggshell. But the cuticle loses effectiveness over time and will be damaged or removed by brushing, washing, or rough handling.
A high-quality interior contains
- no blood or meat spots;
- a round and upstanding yolk;
- thick, not watery, albumen (egg white) held tightly around the yolk; and
- a small air cell.
These interior traits are used to determine not only quality, but also freshness. Over time, evaporation and breakdown of the albumen causes it to become thinner. The air cell also becomes larger. The good news is that this process is slowed by refrigeration, allowing the egg to retain quality and freshness longer.
Washing Eggs
In the United States, most eggs from modern hen houses are visibly clean. However, commercial egg producers are required to wash eggs at specific temperatures to remove any debris or manure particles on the shell as well as use approved sanitizers appropriately. This removes the protective cuticle but decreases the risk of food-borne illness.
Eggs purchased from a grocery store are already washed. You are not required to wash the eggs produced by your home flock for your own consumption, but if you do decide to wash them, follow this important safety advice:
- Agitate, but do not submerge, one egg at a time in water that contains a food-safe detergent and is at least 20°F higher than the internal temperature of the egg, and a minimum of 90°F.
- Do not scrub the shell.
- After washing the egg, rinse it in water that contains an approved sanitizer and is slightly warmer than the wash water.
You need to be careful handling eggs with water because the shell membranes beneath the shell are selectively permeable. Water solutions and gases are able to pass through. Submerging eggs introduces a risk that the water—and any chemicals or pathogens in it—will be absorbed. This risk is increased when the water is colder than the internal temperature of the egg because the contents will contract and pull the water inside. This is a serious food safety concern no matter how clean the water is or the eggs are.
Dry the shell before packaging in a clean carton or flat, then promptly refrigerate.
If you plan to sell your flock's eggs, stay informed about state and federal egg washing requirements.
Water Glassing
Much like with washing, eggs should also not be submerged in water as a preservation strategy. One outdated and potentially dangerous egg preservation method called water glassing is regaining popularity among homesteaders. It uses a solution of sodium silicate into which you submerge unwashed eggs. Water glassing is not recommended.
Why is water glassing dangerous? Remember that the eggshell membrane allows water to pass through. Because of this, there is a risk that the water glassing solution and pathogens will enter the egg. Research done by Hall (1945) and Romanoff (1948) when this method was more widely used, demonstrated that water glassing is ineffective at preserving albumen quality at room temperature (40°-95°F) and changes the odor and flavor of eggs. It is highly unlikely that a cool area of a home, such as a pantry or basement, will reach and maintain proper refrigeration temperatures at or below 40°F. Temperature variation will, therefore, provide opportunities for growth of pathogens, such as Salmonella Enteritidis, that were already inside the egg or that have entered through the eggshell pores, resulting in an unsafe product.
Safe Preservation Options
Thankfully, improvements in refrigeration and freezing technologies have allowed us to move away from unreliable and potentially dangerous preservation methods like water glassing.
Here are some recommendations for safely preserving your eggs:
- According to the United States Department of Agriculture (2019), eggs can be stored in the refrigerator safely for at least one month if they are covered. It is best to store eggs in a carton with the eggs placed ends down. In addition, the refrigeration of raw whole-shell eggs should be maintained at or below 40°F during transport and storage. This slows the rate of quality loss, maintains freshness, and prevents the growth of pathogens.
- While eggs can also be safely frozen to extend the storage time, freezing whole-shell eggs will cause the shell to crack. The National Center for Home Food Preservation (n.d.-a) recommends that you break eggs out first, then freeze as either a whole-egg mixture or as separate yolks and whites. Using ice trays can be a convenient way to store portioned-out servings of eggs.
- Another way to safely store eggs is by pickling. It is important to note that there are no approved canning recipes for pickled eggs and that all pickled egg products require refrigeration for safety. Storing pickled eggs at room temperature can cause botulism. The National Center for Home Food Preservation (n.d.-b) cautions that pickled eggs should be stored in the refrigerator and used within three to four months for the best quality. To further lower the risk of botulism and ensure the safety of the final product, be sure to wash food items and all surfaces, and to sterilize the jars and lids prior to pickling.
- One final way to safely preserve eggs for long-term storage is to use a freeze-dryer. Hirneisen and McGeehan's (2023) Let's Preserve: Freeze-Drying offers information on selecting and using a freeze-dryer. Eggs can be freeze-dried raw or cooked, but if you choose to freeze-dry raw eggs, make sure you label the container accordingly and handle it carefully before and after freeze-drying. Bacteria will not be killed during the freeze-drying process, so it is important to avoid cross-contamination and cook to the proper internal temperature before consuming the product. For storage tips to maximize shelf-life, check out Let's Preserve: Freeze-Drying from Penn State Extension.
By following approved handling and preservation methods, you can safely enjoy the benefits of a backyard flock all year long.
Source : psu.edu