May one use an egg in which he discovered a spot of blood?
Halacha distinguishes in this regard between the two parts of the egg: the yolk, which in Hebrew is called the "Chelmon," and the egg-white, which is called the "Chelbon." (A convenient method of remembering these terms is by associating the word "Chelmon" with "lemon," which is yellow, and the word "Chelbon" with "Chalav," milk, which is white.) If one discovers blood on the white part of the egg, he must simply remove the bloodspot and may then use the egg. If blood appears on the yolk, however, then Halacha forbids using the egg, since blood on the yolk likely represents the early stages of the formation of a new chick, which is forbidden for consumption.
However, this applies only to eggs that were produced through fertilization by a male. In modern chicken coups, eggs are fertilized through other means, not through contact with roosters. Eggs formed through these methods can virtually never develop into a chick, and therefore any blood discovered even on the yolk of such an egg is not forbidden for consumption. And although some companies may, indeed, produce eggs through male fertilization, these eggs represent the minority of eggs sold on the market today, and Halacha allows us to presume that any given egg we purchase belongs to the majority of eggs, which had not been fertilized by males. One who discovers a bloodspot should nevertheless remove the blood to avoid "Mar'it Ayin" (suspicion), but if one forgot to check or to remove a bloodspot that he discovered, the egg may still be used.
Summary: If one discovers a bloodspot in any part of the egg, he should remove it and may then use the egg. If he forgot to check, or if he discovered a bloodspot and forgot to remove it, he may nevertheless use the egg.
See ‘Isur VeHeter’ by Rabbi Yishak Yosef, Page 4, Halacha 3.
