The basic rule of kashrus is that the product of a non-kosher animal is not kosher. Therefore, all eggs from non-kosher birds (and non-kosher fish and animals, such as turtles,) are not kosher.
To be kosher, eggs must come from kosher fowl and be free of bloodspots in the white (albumin) and the yolk. Each egg must be checked individually after it is opened. If there is blood in an egg, it is forbidden.
Eggs from a chicken that died are forbidden by rabbinic enactment.
If eggs are found in a chicken after shechita, they are considered meat and need to be kashered. (They should be soaked and salted by themselves.)
If an egg containing an embryo is cooked together with other eggs, none of the eggs are kosher.
1. Blood Spots:
a. If the blood is in the kesher-knot, it is forbidden by the Torah.
b. If there is blood in any egg, it is forbidden.
Today most eggs are non-fertilized and are not forbidden from the Torah.
2. The Halacha says there are two ways to identify a kosher egg. It will have one side round and one side pointed and a yolk inside with white around it.
Fortified eggs – means eggs that have extra yolk added to them. Eggs are used in many foods. Some are:
a. Pasta: Egg white for a binder and yolk for color.
b. Ice cream: egg yolk for color (all natural yellow vanilla)
c. French ice cream : frozen custard must have at least 2.8 percent egg yolk.
d. Egg Albumin: stabilizer, thickener, texturizer, in baked goods, candies, fruit drinks, frostings, mayonnaise, baked goods.
Reb Moshe Feinstein, ZT”L states the following concerning unfertilized eggs: “Concerning eggs that are unfertilized, only the blood spot within them would have to be removed, not the whole egg. Of concern, I spoke to a farmer who told me that deals in fertilized and unfertilized eggs… and when he has an overabundance of fertilized eggs, he adds them to the unfertilized eggs for sale in supermarkets. However, it is clear that not too many farmers do this, and those who do only do so with a few eggs.” Therefore, if one buys an egg from the store in the United States, it can be considered a kosher egg, even without checking it. However, it is common custom to check all eggs for bloodspots and to treat them as if they were fertilized.
(Though this is the actual Halacha, since many rabbis have been very strict in this regard, it is good not to be lenient with eggs. Therefore, if a person knows that eggs are being purchased from a farmer who raises both fertilized and unfertilized eggs, even though they are probably unfertilized, we tend to be strict. On the other hand, if two eggs from the supermarket are cooked together in one pot, even if the larger egg is found to have a bloodspot, we only need to remove the egg with the bloodspot and the other one can be eaten. The exception to this is if the bloodspot is in the yolk andthe white part of the egg (which is very rare). In that case, we tend to be even stricter. (Synopsis of responsa from Rav Moshe Feinstein on eggs.)
Two types of egg substitutes are available, one for the general public and the other for commercial use by bakeries.
The general public can purchase an egg substitute made from egg whites, vegetable oil, nonfat dry milk, emulsifiers, and artificial flavors and colors. Such products present no problems to certification agencies if the individual ingredients are kosher. If a certified version of these products can be found, the kosher consumer will find them excellent for making scrambled eggs and as substitutes for fresh eggs in recipes. It is for the latter use that commercial bakeries purchase egg substitutes.
An extract of cod or haddock (both kosher fish) can be used to make a “substitute egg white.” A derived protein from skim milk, can be used like the fish protein as a powdered egg (see albumin) substitute. These two egg substitutes can theoretically be produced under kosher supervision, although the halacha opposes the introduction of dairy products into breads. A third source of egg substitutes is plasma obtained from blood. This substance would render any product in which it is found not kosher.
Food producers also use frozen or powdered eggs instead of whole fresh eggs. These must be certified kosher since there is a real possibility that eggs from a non-kosher species may be added, especially if cheaper, imported eggs are used. The Japanese have a large market for frozen and powdered eggs in this country. Therefore, products listing powdered or frozen eggs as ingredients must have supervision.
Another cheaper substitute for fresh whole eggs is the ova, the egg found in a hen after slaughter. Due to the fact that these are non-kosher eggs, they present a serious kashrus problem. Although a blood spot renders the egg not kosher, governmental regulations require only the removal of the blood, not the disposal of the egg itself. It is important for the kosher consumer to realize that in this area, the government is more lenient than Jewish law.