Courtesy: Kosher food approval certification
Human breast milk
Breast milk from a woman is permitted. However, authorities assert breast milk may be consumed directly from the breasts only by children younger than four (five if the child is ill), and children older than two were only permitted to continue to suckle if they had not stopped doing so for more than three consecutive days.
Cheese
The situation of cheese, is complicated as hard cheese usually involves rennet, an enzyme that splits milk into curds and whey.
Most forms of rennet were formerly derived from the stomach linings of animals, but currently rennet is most often made recombinantly in microbes (though most European cheese still uses animal rennet).
Because the rennet could be derived from animals, it could potentially be non-kosher. Only rennet made recombinantly, or from the stomachs of kosher animals, if they have been slaughtered according to the laws of kashrut, is kosher.
According to the Shulchan Aruch, a rabbinic decree (called gevinat akum) prohibits all cheese made by non-Jews without Jewish supervision, even if its ingredients are all kosher, because very frequently the rennet in cheese is not kosher.. Rabbeinu Tam and some of the geo nimsuggested that this decree does not apply in a location where cheese is commonly made with only kosher ingredients, a position that was practiced in communities in Narbonne and Italy.
Many contemporary Orthodox authorities do not follow this ruling, and hold that cheese requires formal kashrut certification to be kosher; some even argue this is necessary for cheese made with non-animal rennet. However, some such as Rabbi Joseph B. Soloveitchik ate generic cheeses without certification. Isaac Klein’s tshuva authorized the use of cheese made from non-kosher rennet, and this is widely practised by observant Conservative Jews and Conservative institutions
Eggs
Jerusalem kugel made with egg noodle, caramelized sugar and black pepper
The eggs of kosher birds are kosher. Eggs are considered pareve despite being an animal product.
Blood found in eggs
Occasionally blood spots are found within an egg, which can affect the kosher status of the egg. The halacha varies depending on whether or not there is a possibility of the egg being fertilized.
If the egg may have been fertilized, the Rishonim and Shulchan Aruch suggest a complex set of rules for determining whether the egg may be eaten; among these rules, if blood appears on the yolk, the entire egg is forbidden. To avoid the complexity of these rules, R’ Moshe Isserles records a custom not to eat any such eggs with blood spots.
If the egg was definitely unfertilized (laid by a hen kept isolated from roosters), many authorities (including Rabbis Moshe Feinstein and Ovadiah Yosef) rule that one may remove the blood spot and then eat the remainder of the egg. This is the case nowadays, when battery eggs form the majority of available produce.
Regarding the question of whether one must check an egg for blood spots, the Shulchan Aruch rules that one may eat hard-boiled eggs where checking is impossible. R’ Moshe Isserles adds that checking is not required, but that a custom exists to check eggs if they are cracked during the daytime (when blood could be seen).
A contemporary Ashkenazi authority writes that while “halacha does not require” checking supermarket-bought eggs, “there is a minhag” to do so. Nevertheless, eggs are not checked in commercial settings where doing so would be expensive