Kosher foods are those that conform to the rules of
Jewish religion. These rules form the main aspect of
kashrut,
Jewish dietary laws.
Reasons for food being non-kosher include the presence of ingredients derived from non-kosher animals or from kosher animals that were not properly slaughtered, a mixture of meat and milk, wine or grape juice (or their derivatives) produced without supervision, the use of produce from Israel that has not been
tithed, or even the use of cooking utensils and machinery which had previously been used for non-kosher food.
In
Judaism most of the laws of
Kashrut pertain to animals. The
Torah explicitly states which animals are permitted or forbidden. In regard to birds, the Torah provides no general rule, and instead the Deuteronomic Code and Priestly Code explicitly list the prohibited birds, using names that have uncertain translations; the list seems to mainly consist of
birds of prey, fish-eating water-birds, and the bat.
By contrast, for water creatures, Leviticus and Deuteronomy both give the general rule that anything residing in
the waters (which Leviticus specifies as being the seas and rivers) is ritually
clean if it has both fins and scales, in contrast to anything residing in the
waters with neither fins nor scales,
which Leviticus calls
filthy (Hebrew:
sheqets). All
flying creeping things were also to be considered ritually
unclean, according to both Leviticus and Deuteronomy, but unlike Deuteronomy, Leviticus identifies four exceptions; the exceptions are of uncertain translation, but are clearly locusts and similar creatures, and there is a tradition upheld by Jews from Yemen about which animals constitute the
kosher locusts.
With regard to land
beasts (Hebrew:
Behemoth), Deuteronomy and Leviticus both state that anything which
chews the cud and has a
cloven hoof would be ritually
clean, but those animals which only
chew the cud or only have
cloven hooves would be
unclean.
The texts identify four animals in particular as being unclean for this reason - the hare,
hyrax, camel, and pig — although the camel both ruminates and has two toes, while the hare and hyrax are
coprophages rather than ruminants; the latter issues have been discussed by many, including the recent book on the subject by Rabbi
Natan Slifkin Leviticus, but not Deuteronomy, also states that every
creeping thing which creeps upon the earth should be considered
filthy.
Since the Bible prohibits eating meat from animals dying from natural causes, and all animals killed by beasts, traditional Jewish thought has expressed the view that all meat must come from animals which have been slaughtered according to Jewish law. These strict guidelines require that the animal is killed by a single cut across the throat to a precise depth, severing both carotid arteries, both jugular veins, both vagus nerves, the trachea and the esophagus, no higher than the epiglottis and no lower than where cilia begin inside the trachea, causing the animal to bleed to death. Orthodox Jews argue that this ensures the animal dies instantly without unnecessary suffering, but many animal rights activists view the process as cruel, arguing that the animal may not lose consciousness immediately, and activists have called for it to be banned.[60][61]
To avoid tearing, and to ensure the cut is thorough, such slaughter is usually performed by a trained individual, with a large razor-sharp knife, which is checked before each killing to ensure that it has no irregularities (such as nicks and dents); if irregularities are discovered, or the cut is too shallow, the meat is deemed not kosher, and is sold to the non-Jewish public. Rabbis usually require the slaughterer, known within Judaism as a shochet, to also be a pious Jew of good character, who observes the Shabbat, and believes that the slaughter victims are sacrificing their lives for the good of the slaughterer and their community. In smaller communities the shochet was often the town rabbi, or a rabbi from a local synagogue, but large slaughterhouses usually employ a full-time shochet if they intend to sell kosher meat.
During Passover, there are additional food restrictions in Orthodox Judaism; in this branch of Judaism, leavened products are prohibited during the festival. Jews who are concerned about accidentally consuming leavened food, during passover, typically maintain an entirely separate set of crockery and cutlery for Passover; it is also common for those concerned about such things to rigorously clean their homes, to ensure that even the tiniest of remains of leavened products are removed. Some Jews even have a separate kitchen exclusively for use during Passover.
Products made from the traditional five species of grain, which might have been inadvertently moistened after harvest, and thus begun to ferment (an aspect of the leavening process), are regarded by Orthodox Jews as prohibited during Passover; the five species are conventionally viewed to be wheat, rye, barley, spelt and oats, although the latter two may actually refer to emmer (sometimes confused with spelt, which did not historically grow in the Middle East) and two-rowed barley.[citation needed]
Among the Ashkenazi Jews there is an additional customary practice of avoiding the consumption of kitniyot (literally meaning little things) during Passover; the list of items regarded as kitniyot varies between communities, and can include things such as rice, legumes (including peas, peanuts, and beans), and corn. Due to the prevalence of corn syrup in certain well-known processed foods, such as Coca-Cola, many items common in western countries are regarded as impermissible by Ashkenazic Jews during Passover. [For Passover consumption, some companies produce products similar to their standard versions but with Kosher-for-Passover ingredients. Coca-Cola, for example, produces and distributes kosher for Passover Coke, made with cane sugar instead of corn syrup, in the U.S. during Passover since Rabbi Tobias Geffen certified Coca-Cola as kosher
