Of the "beasts of the earth"
(basically mammals with the exception of rodents), you may eat any animal
that has cloven hooves and chews its cud. Any land mammal that does
not have both of these qualities is forbidden. Sheep, cattle, goats
and deer are kosher.
Of the animals that may be eaten,
the birds and mammals must be killed in accordance with Jewish law.
All blood must be drained from the meat or broiled out of it before
it is eaten. Certain parts of permitted animals may not be eaten.
The flesh of birds and mammals cannot
be eaten with dairy. Fish, eggs, fruits, vegetables and grains can be
eaten with either meat or dairy. (According to some views, fish may
not be eaten with meat).
Utensils that have come into contact
with meat may not be used with dairy, and vice versa. Utensils that
have come into contact with non-kosher food may not be used with kosher
food. This applies only where the contact occurred while the food was
hot.
Grape products made by non-Jews
may not be eaten.
Anything in the water that has
fins and scales is acceptable. This therefore excludes shellfish such
as lobsters, oysters, shrimp, clams and crabs, all of which are forbidden.
For birds, the criteria is less
clear. The "Torah" lists forbidden birds without specifying
why they are forbidden. All of the birds on the list are birds of prey
or scavengers, thus the rabbis inferred that this was the basis for
the distinction. Other birds are permitted, such as chicken, geese,
ducks and turkeys.
Rodents, reptiles, amphibians, and
insects are all forbidden.
Some authorities require a post-mortem
examination of the lungs of cattle, to determine whether the lungs are
free from adhesions. If the lungs are free from such adhesions, the
animal is deemed "glatt" (that is, "smooth"). In
certain circumstances, an animal can be kosher without being glatt;
however, the stringency of keeping "glatt kosher" has become
increasingly common in recent years.
As mentioned above, any product
derived from these forbidden animals, such as their milk, eggs, fat,
or organs, also cannot be eaten. Rennet, an enzyme used to harden cheese,
is often obtained from non-kosher animals, thus kosher hard cheese can
be difficult to find.
In regard to meat, all blood must
be drained before the meat is cooked and eaten, because blood, which
gives life, is sacred to God. In temple services, blood was offered
on the altar separately from the rest of the sacrificed animal, and
only meat without blood could be eaten by the priests and sharers in
the sacred meal (see Lev. 17). This rule also ensured that animals that
had died in the field or were killed by larger animals carcasses that
might be unsafe to eat could not be consumed (see Exod. 22:31). In practice,
there are very specific methods of kosher slaughter, inspection, and
preservation.
For religious Jews, meat and dairy
products may not be mixed or eaten together at the same meal. This also
means that a household that keeps kosher must maintain separate sets
of cooking implements, pans, dishes, and utensils one for meat and one
for dairy products. Some households even have separate sinks. These
practices derive from a rule of uncertain origin that forbids the cooking
of a baby goat or lamb in its mothers milk (Exod. 34:26). It is
possible the practice was forbidden for being cruel: some fetal animals,
cut from the womb before birth, were considered tender delicacies. The
practice of cooking a kid in its mothers milk may also have been
associated with non-Hebrew religious practice and therefore forbidden.
These are the laws that govern Jewish
cooking. To understand how an Italian dish, risotto, for example, might
be cooked, we need to understand the rules of Kosher cooking. Risotto
to a Christian Italian might be made with a meat stock, vegetables,
then sprinkled with cheese. This combination, being forbidden to Jews,
would be simplified by eliminating either the meat stock or the cheese.
The choice would be up to the cook.