|
Cleanliness | Contamination | Doneness | Pasteurization | Proper Storage
Cleanliness
It is important to follow the basic rules of cleanliness and proper hygiene when preparing eggs and egg products. Wash your hands before and after egg preparation. If multiple foods are being prepared at one time, your hands should be washed thoroughly after preparing each different food item to avoid spreading possible bacteria from one food to another (cross contamination) and to yourself.
Cutting boards used in the kitchen are best when they are constructed of non-porous materials such as tempered glass or heavy plastic. Tempered glass cutting boards are safer to use because there is less of a problem with cracks and pores harboring bacteria as there is with wood or soft plastic surfaces. Cutting boards should be washed thoroughly after each use with hot, soapy water. A mixture of bleach and water or an antibacterial spray can also be used to kill germs. All other work surfaces, such as countertops, and all utensils used in food preparation should also be thoroughly cleaned.
Beware of kitchen washcloths and towels that have been used on multiple surfaces because they can spread germs. Use paper towels or other disposable cloths whenever possible. Eggs that are cracked, leaking, and/or soiled should not be used.
Contamination
Egg Contamination
The risk of eggs being contaminated with harmful bacteria and causing illness is very low. The odds of becoming ill from consuming eggs is no greater than with any other perishable type of food and the risk is often less than many foods. It is estimated that only 0.005% (1 in 20,000) of eggs may be contaminated with the salmonella bacteria, but even with a risk this low, it is wise to cook eggs to the proper doneness to ensure safety. Proper cooking kills the salmonella bacteria in any eggs that may have it.
The eggshell is a good natural barrier for preventing bacteria from entering the egg, but since it is porous, it does not guarantee that an egg will remain germ free. Other barriers, such as the shell membrane, the four layers of the white, and the yolk membrane (vitelline) help to prevent bacteria from entering the yolk, which is a perfect environment for bacteria to thrive.
The eggshell may contain other types of bacteria and dirt, so in the United States, eggs are thoroughly washed before they are sold to the consumer. After sanitizing, eggs are usually given a light spray of mineral oil to coat the shell, replacing the natural protective coating that was lost during the washing.
In eggs that are contaminated with salmonella, the bacteria are more likely to be found in the white, but are unable to thrive because of the lack of nutrients. The white is an alkaline substance which also discourages the growth of bacteria. The egg white acts as a natural protection for the yolk, preventing bacteria from entering the yolk and thriving in the nutrient rich environment. The white thins out as the egg ages, which makes it easier for bacteria to reach the yolk.
Refrigeration slows bacterial growth, so it is important to properly store eggs. Never use eggs that are cracked or leaking or stuck to the bottom of the carton. Even if there isn't a visible crack, an egg that is stuck to the carton, even slightly, may indicate that it has leaked and should not be used.
Cross Contamination
Cross contamination is also important to guard against. Various types of foods should be kept separate from each other during storage and preparation. Never store ready to eat foods next to raw eggs, raw meats, or raw fish. Germs from perishable food items may contaminate the ready to eat foods. If cutting boards are used in your kitchen, it is a good idea to use one for meats and a different one for fruits and vegetables. Never use the same knives and utensils for preparing multiple food items unless they are washed before using them on a different item. The knife that was used to cut raw beef should not be used to chop a hard-cooked egg unless the knife has been thoroughly washed first. It is also important to wash your hands often during food preparation to avoid transferring harmful bacteria from one food item to the next. If you were handling raw meat, for example, you would want to wash your hands thoroughly before chopping vegetables to reduce the risk of transferring bacteria from the meat to the vegetables.
Additional Points to Consider Concerning Contamination
- It is best not to separate egg whites and yolks by splitting open the eggshell and passing the contents between the two shell halves. The egg may become contaminated if bacteria are present on the shell. Bacteria may be present on the shell even after it is cleaned and the shell may also become contaminated from other food sources that it may come in contact with.
- Do not use the two halves of the shell for removing bits of the shell from an egg mixture and never use the shell halves to measure other foods for a recipe.
- Salmonella may be found not only in eggs, but in other foods such as chicken, cheese, orange juice, tomatoes, and alfalfa sprouts. It can be spread quite easily from one food to another, which is why it is important to guard against cross contamination during food preparation.
- Cross contamination can occur when bacteria are transferred from one food to another, from contaminated kitchen equipment to food, or from people to food.
- The number of incidents of people becoming infected from salmonella in eggs has steadily declined during the past few years. This is due mainly to quality control measures on the farm, in processing facilities, and during shipping to food stores and also because of increased awareness of proper food handling procedures by food service personnel and consumers.
Doneness
The best way to guard against the spread of bacteria and foodborne illness is to cook eggs thoroughly. Cooking eggs thoroughly does not mean that the eggs should be overcooked, which can make them tough and rubbery. It simply means the eggs should be cooked to a temperature that kills any bacteria that may be present. Most harmful bacteria cannot survive in a temperature of 160°F or greater. In fact, salmonella is killed instantly when subjected to a temperature of 160°. An egg (white and yolk) requires a temperature of up to 158°F before it sets properly. The white alone requires a somewhat lower temperature before it coagulates, usually in the 140° to 150° range. These temperatures are only slightly less than what is required to destroy all of the harmful bacteria that may be present, so heating eggs to 160° F should not cause eggs to be overcooked, unless they are held at that temperature (or higher) for an extended period.
Cooking eggs slowly with heat that is not too high should destroy harmful bacteria as well as allow for proper doneness. There are exceptions to this, such as when cooking a plain omelet. The eggs are cooked very quickly, but the heat is also much higher, which takes care of any possible bacterial contamination. Baked egg dishes can be checked using a kitchen thermometer placed in the center of the dish. The thermometer should register 160°F to ensure proper doneness.
Eggs cooked in the microwave may not cook evenly, so it is important to rotate the dish several times during the cooking process. Covering the dish during microwave cooking is recommended because steam is trapped inside the dish, which helps to cook the eggs more quickly and evenly and keeps them from drying out.
Pasteurization
Pasteurized Egg Products
In the United States, all egg products that are distributed to the consumer must be pasteurized. The products include whole eggs, whites, and yolks that may or may not be blended with other ingredients to add volume or flavor. The pasteurization process destroys any harmful bacteria that may be present in the eggs at the time of processing, but it does not guard against future contamination. It is important to properly handle and store pasteurized egg products to help prevent future contamination. Egg products are typically produced in liquid, dried, or frozen varieties. Look for the USDA mark of inspection on pasteurized products.
Pasteurized Shell Eggs
Pasteurized shell eggs are heated for a period of time to destroy any bacteria that might be present, but the process does not cook the eggs. The eggs are safer to use for a number of recipes that traditionally call for the use of raw or partially cooked eggs, however the USDA still recommends using the eggs in dishes that are fully cooked, especially when serving the dish to higher risk persons such as people with weakened immune systems, young children, or elderly people.
There is no difference in the outcome of cooked or baked egg dishes when using pasteurized shell eggs as opposed to untreated eggs, however there is a noticeable difference between pasteurized and non-pasteurized shell eggs in the time required for beating the egg whites into peaks. Pasteurized egg whites may require 3 to 5 times the beating time required for untreated eggs. Instead of using whole pasteurized shell eggs for recipes requiring beaten egg whites, you can use pasteurized egg whites that are in a liquid state or have been dried into a powder. Some pasteurized egg white products are available containing no other ingredients while some contain additives that help in building volume when beating egg whites and to stabilize the foam.
Proper Storage
Eggs should never be stored at room temperature, but there are recipes that require eggs to be at or near room temperature before incorporating them into the other ingredients in the recipe. Egg whites that will be beaten should be at room temperature because this helps the whites to reach their maximum volume when beaten. Approximately 30 minutes is required for eggs to reach room temperature after removing them from the refrigerator. Eggs should not be away from refrigeration for more than 2 hours, so the time required to allow the eggs to warm to room temperature, as well as the total preparation time of the recipe, should not exceed the 2 hour maximum. This should be considered when planning the steps required for the preparation of a recipe using eggs that must be at room temperature.
Refrigerator Storage
Eggs should be stored in the refrigerator in the carton they were packed in. Many refrigerators provide storage for eggs in special units in the door, but this is not the ideal place for storing eggs because the temperature fluctuates so much in the door when it is opened and closed. Eggs should be stored in the coldest part of the refrigerator where the temperature remains constant. Eggs keep best when they are stored at temperatures of no higher than 40°F. The ideal temperature range is 33°F to 38°F. When the temperature is above 40°F, harmful bacteria may grow rapidly. Although salmonella are not destroyed in temperatures below 40°F, any of the bacteria that may be present will not multiply when the temperature is below 40°F.
Eggs should be stored with the rounded end pointed up in order to keep the air cell on top and to help keep the yolk centered in the egg. Never store eggs next to strong smelling foods because eggshells are porous and will allow strong odors to be absorbed into the egg over time. This is another reason why it is a good idea to store eggs in the original protective carton.
Freezer Storage
For long term storage, eggs and egg products may be frozen. If stored properly, eggs will emerge from the freezer no better or worse, in terms of quality, than when they first entered the freezer. The temperature of the freezer compartment must be at 0°F or less and the eggs should be stored in an area of the freezer where there is the least amount of temperature change. Eggs and egg products should not be stored in the door compartment of the freezer, especially if the door is opened frequently.
Whole eggs can be beaten slightly and placed in a container with a tight seal and stored in the freezer for as long as a year. Egg whites may be stored in the freezer for up to a year in a tightly sealed container. Egg yolks may also be stored in the freezer, but sugar or salt must be added to keep the yolks from becoming too thick and gelatinous over time. Add a pinch of salt per yolk if the yolks will be used for savory dishes or about a ¼ teaspoon of sugar per yolk if the yolks will be used for sweet dishes.
Like other perishable foods that have been frozen, eggs should be defrosted in the refrigerator and should never be allowed to thaw at room temperature. Thawing foods on the countertop encourages the the growth of harmful bacteria, especially on the outside edges of the food. | 
