Kashrut: Jewish Dietary Laws
Kashrut is a set of biblical dietary restrictions
Certain foods cannot be eaten
Certain foods must be separated
Certification makes it easier to identify kosher food
Kashrut is the body of Jewish law dealing with what foods we can and cannot eat
and how those foods must be prepared and eaten. "Kashrut" comes from the Hebrew
root Kaf-Shin-Reish, meaning fit, proper or
correct. It is the same root as the more commonly known word "kosher," which
describes food that meets these standards. The word "kosher" can also be used,
and often is used, to describe ritual objects that are made in accordance with
Jewish law and are fit for ritual use.
Contrary to popular misconception, rabbis or other religious officials do not
"bless" food to make it kosher. There are blessings that observant Jews recite
over food before eating it, but these blessings have nothing to do with making
the food kosher. Food can be kosher without a rabbi or priest ever becoming
involved with it: the vegetables from your garden are undoubtedly kosher (as
long as they don't have any bugs, which are not kosher!). However, in our
modern world of processed foods, it is difficult to know what ingredients are
in your food and how they were processed, so it is helpful to have a rabbi
examine the food and its processing and assure kosher consumers that the food
is kosher. This certification process is discussed
Kosher dietary laws are observed all year round, not just during
Pesach (Passover). There are additional dietary
restrictions during Pesach, and many foods that are kosher for year-round use
are not "kosher for Passover." A bagel, for example, can be kosher for
year-round use but is certainly not kosher for Passover! Foods that are kosher
for Passover, however, are always kosher for year-round use.
There is no such thing as "kosher-style" food. Kosher is not a style of
cooking. Chinese food can be kosher if it is prepared in accordance with Jewish
law, and there are many fine kosher Chinese restaurants in Philadelphia and New
York. Traditional Ashkenazic Jewish foods like
matzah ball soup can all be non-kosher if not
prepared in accordance with Jewish law. When a restaurant calls itself
"kosher-style," it usually means that the restaurant serves these traditional
Jewish foods, and it almost invariably means that the food is not actually
Food that is not kosher is commonly referred to as treif (lit. torn, from the
commandment not to eat animals that have been torn by other animals).
Why Do We Observe the Laws of Kashrut?
Many modern Jews think that the laws of kashrut are simply primitive health
regulations that have become obsolete with modern methods of food preparation.
There is no question that some of the dietary laws have some beneficial health
effects. For example, the laws regarding kosher slaughter are so sanitary that
kosher butchers and slaughterhouses have been exempted from many USDA
However, health is not the only reason for Jewish dietary laws. Many of the
laws of kashrut have no known connection with health. To the best of our modern
scientific knowledge, there is no reason why camel or rabbit meat (both treif)
is any less healthy than cow or goat meat. In addition, some of the health
benefits to be derived from kashrut were not made obsolete by the refrigerator.
For example, there is some evidence that eating meat and dairy together
interferes with digestion, and no modern food preparation technique reproduces
the health benefit of the kosher law of eating them separately.
In recent years, several secular sources that have seriously looked into this
matter have acknowledged that health does not explain these prohibitions. Some
have suggested that the prohibitions are instead derived from environmental
considerations. For example, a camel (which is not kosher) is more useful as a
beast of burden than as a source of food. In the Middle Eastern climate, the
pig consumes a quantity of food that is disproportional to its value as a food
source. But again, these are not reasons that come from Jewish tradition.
The short answer to why Jews observe these laws is: because the
Torah says so. The Torah does not specify any
reason for these laws, and for a Torah-observant, traditional Jew, there is no
need for any other reason. Some have suggested that the laws of kashrut fall
into the category of "chukkim," laws for which there is no reason. We show our
obedience to G-d by following these laws even though
we do not know the reason. Others, however, have tried to ascertain G-d's
reason for imposing these laws.
In his book "To Be a Jew" (an excellent resource on traditional Judaism), Rabbi
Hayim Halevy Donin suggests that the dietary laws are designed as a call to
holiness. The ability to distinguish between right and wrong, good and evil,
pure and defiled, the sacred and the profane, is very important in Judaism.
Imposing rules on what you can and cannot eat ingrains that kind of self
control, requiring us to learn to control even our most basic, primal
Donin also points out that the laws of kashrut elevate the simple act of eating
into a religious ritual. The Jewish dinner table is often compared to the
Temple altar in rabbinic
literature. A Jew who observes the laws of kashrut cannot eat a meal
without being reminded of the fact that he is a Jew.
How Difficult is it to Keep Kosher?
People who do not keep kosher often tell me how difficult it is. Actually,
keeping kosher is not particularly difficult in and of itself; what makes it
difficult to keep kosher is the fact that the rest of the world does not do so.
As we shall see below, the basic underlying rules are fairly simple. If you buy
your meat at a kosher butcher and buy only kosher
certified products at the market, the only thing you need to think about is
the separation of meat and dairy.
Keeping kosher only becomes difficult when you try to eat in a non-kosher
restaurant, or at the home of a person who does not keep kosher. In those
situations, your lack of knowledge about your host's ingredients and food
preparation techniques make it very difficult to keep kosher. Some commentators
have pointed out, however, that this may well have been part of what G-d had in
mind: to make it more difficult for us to socialize with those who do not share
Although the details of kashrut are extensive, the laws all derive from a few
fairly simple, straightforward rules:
- Certain animals may not be eaten at all. This restriction includes the
flesh, organs, eggs and milk of the forbidden animals.
- 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 meat and poultry or broiled out of it before
it is eaten.
- Certain parts of permitted animals may not be eaten.
- Fruits and vegetables are permitted, but must be inspected for bugs (which
cannot be eaten)
- Meat (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 (including pots and pans and other cooking surfaces) 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
- Grape products made by non-Jews may not be eaten.
- There are a few other rules that are not universal.
Animals that may not be eaten
Of the "beasts of the earth" (which basically refers to land mammals with the
exception of swarming rodents), you may eat any animal that has cloven hooves
and chews its cud. Lev. 11:3; Deut. 14:6. Any land mammal that does not have
both of these qualities is forbidden. The Torah
specifies that the camel, the rock badger, the hare and the pig are not kosher
because each lacks one of these two qualifications. Cattle, sheep, goats, deer
and bison are kosher.
Of the things that are in the waters, you may eat anything that has fins and
scales. Lev. 11:9; Deut. 14:9. Thus, shellfish such as lobsters, oysters,
shrimp, clams and crabs are all forbidden. Fish like tuna, carp, salmon and
herring are all permitted.
For birds, the criteria is less clear. The Torah
provides a list of forbidden birds (Lev. 11:13-19; Deut. 14:11-18), but does
not specify why these particular birds 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. However, some people avoid turkey, because it is was unknown at the
time of the giving of the Torah, leaving room for doubt.
Of the "winged swarming things" (winged insects), a few are specifically
permitted (Lev. 11:22), but the Sages are no longer certain which ones they
are, so all have been forbidden. There are communities that have a tradition
about what species are permitted, and in those communities some insects are
Rodents, reptiles, amphibians, and insects (except as mentioned above) are all
forbidden. Lev. 11:29-30, 42-43.
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, and you would be hard-pressed to find any kosher meat that is not
labeled as "glatt kosher."
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.
The mammals and birds that may be eaten must be slaughtered in accordance with
Jewish law. (Deut. 12:21). We may not eat animals that died of natural causes
(Deut. 14:21) or that were killed by other animals. In addition, the animal
must have no disease or flaws in the organs at the time of slaughter. These
restrictions do not apply to fish; only to the flocks and herds (Num. 11:22).
Ritual slaughter is known as shechitah, and the person who performs the
slaughter is called a shochet, both from the Hebrew
root Shin-Cheit-Teit. The method of slaughter is a
quick, deep stroke across the throat with a perfectly sharp blade with no nicks
or unevenness. This method is painless, causes unconsciousness within two
seconds, and is widely recognized as the most humane method of slaughter
Another advantage of shechitah is that it ensures rapid, complete draining of
the blood, which is also necessary to render the meat kosher.
The shochet is not simply a butcher; he must be a pious man, well-trained in
Jewish law, particularly as it relates to kashrut. In smaller, more remote
communities, the rabbi and the shochet were often
the same person.
Draining of Blood
The Torah prohibits consumption of blood. Lev.
7:26-27; Lev. 17:10-14. This is the only dietary law that has a reason
specified in Torah: we do not eat blood because the life of the animal
(literally, the soul of the animal) is contained in the blood. This applies
only to the blood of birds and mammals, not to fish blood. Thus, it is
necessary to remove all blood from the flesh of kosher animals.
The first step in this process occurs at the time of slaughter. As discussed
above, shechitah allows for rapid draining of most of the blood.
The remaining blood must be removed, either by broiling or soaking and salting.
Liver may only be kashered by the broiling method, because it has so much blood
in it and such complex blood vessels. This final process must be completed
within 72 hours after slaughter, and before the meat is frozen or ground. Most
butchers and all frozen food vendors take care of the soaking and salting for
you, but you should always check this when you are buying someplace you are
An egg that contains a blood spot may not be eaten. This isn't very common, but
I find them once in a while. It is a good idea to break an egg into a glass and
check it before you put it into a heated pan, because if you put a
blood-stained egg into a heated pan, the pan becomes non-kosher. If your recipe
calls for multiple eggs, break each one into the glass separately, so you don't
waste all of the eggs if the last one is not kosher!
Forbidden Fats and Nerves
The sciatic nerve and its adjoining blood vessels may not be eaten. The process
of removing this nerve is time consuming and not cost-effective, so most
American kosher slaughterers simply sell the hind quarters to non-kosher
A certain kind of fat, known as chelev, which surrounds the vital organs and
the liver, may not be eaten. Kosher butchers remove this. Modern scientists
have found biochemical differences between this type of fat and the permissible
fat around the muscles and under the skin.
Fruits and Vegetables
All fruits and vegetables are kosher (but see the note regarding
Grape Products below). However, bugs and worms that may be
found in some fruits and vegetables are not kosher. Fruits and vegetables that
are prone to this sort of thing should be inspected to ensure that they contain
no bugs. Leafy vegetables like lettuce and herbs and flowery vegetables like
broccoli and cauliflower are particularly prone to bugs and should be inspected
carefully. Strawberries and raspberries can also be problematic. The
certification organization has a very nice overview of the fruits and
vegetables prone to this and the procedure for addressing it in each type.
Separation of Meat and Dairy
On three separate occasions, the Torah tells us
not to "boil a kid in its mother's milk." (Ex. 23:19; Ex. 34:26; Deut. 14:21).
The Oral Torah explains that this passage prohibits
eating meat and dairy together. The rabbis
extended this prohibition to include not eating milk and poultry together. In
addition, the Talmud prohibits cooking meat and
fish together or serving them on the same plates, because it is considered to
be unhealthy. It is, however, permissible to eat fish and dairy together, and
it is quite common (lox and cream cheese, for example). It is also permissible
to eat dairy and eggs together.
This separation includes not only the foods themselves, but the utensils, pots
and pans with which they are cooked, the plates and flatware from which they
are eaten, the dishwashers or dishpans in which they are cleaned, the sponges
with which they are cleaned and the towels with which they are dried. A kosher
household will have at least two sets of pots, pans and dishes: one for meat
and one for dairy. See Utensils below for more details.
One must wait a significant amount of time between eating meat and dairy.
Opinions differ, and vary from three to six hours after meat. This is because
fatty residues and meat particles tend to cling to the mouth. From dairy to
meat, however, one need only rinse one's mouth and eat a neutral solid like
bread, unless the dairy product in question is also of a type that tends to
stick in the mouth.
The Yiddish words fleishik (meat), milchik
(dairy) and pareve (neutral) are commonly used to describe food or utensils
that fall into one of those categories.
Note that even the smallest quantity of dairy (or meat) in something renders it
entirely dairy (or meat) for purposes of kashrut. For example, most margarines
are dairy for kosher purposes, because they contain a small quantity of whey or
other dairy products to give it a buttery taste. Animal fat is considered meat
for purposes of kashrut. You should read the ingredients very carefully, even
if the product is kosher-certified.
Utensils (pots, pans, plates, flatware, etc., etc.) must also be kosher. A
utensil picks up the kosher "status" (meat, dairy, pareve, or treif) of the
food that is cooked in it or eaten off of it, and transmits that status back to
the next food that is cooked in it or eaten off of it. Thus, if you cook
chicken soup in a saucepan, the pan becomes meat. If you thereafter use the
same saucepan to heat up some warm milk, the fleishik status of the pan is
transmitted to the milk, and the milchik status of the milk is transmitted to
the pan, making both the pan and the milk a forbidden mixture.
Kosher status can be transmitted from the food to the utensil or from the
utensil to the food only in the presence of heat, (including hot spices) or
prolonged contact, thus if you are eating cold food in a non-kosher
establishment, the condition of the plates is not an issue. I knew an Orthodox
rabbi who would eat ice cream at Friendly's, for example, because the ice cream
was kosher and the utensils are irrelevant for such cold food. Likewise, you
could use the same knife to slice cold cuts and cheese, as long as you clean it
in between, but this is not really a recommended procedure, because it
increases the likelihood of mistakes.
Stove tops and sinks routinely become non-kosher utensils, because they
routinely come in contact with both meat and dairy in the presence of heat. It
is necessary, therefore, to use dishpans when cleaning dishes (don't soak them
directly in the sink) and to use separate spoon rests and trivets when putting
things down on the stove top.
Dishwashers are a kashrut problem. If you are going to use a dishwasher for
both meat and dairy in a kosher home, you either need to have separate dish
racks or you need to run the dishwasher in between meat and dairy loads.
You should use separate towels and pot holders for meat and dairy. Routine
laundering kashers such items, so you can simply launder them between using
them for meat and dairy.
Certain kinds of utensils can be "kashered" if you make a mistake and use it
with both meat and dairy. Consult a rabbi for
guidance if this situation occurs.
The restrictions on grape products derive from the laws against using products
of idolatry. Wine was commonly used in the rituals of all ancient religions,
and wine was routinely sanctified for pagan purposes while it was being
processed. For this reason, use of wines and other grape products made by
non-Jews was prohibited. (Whole grapes are not a problem, nor are whole grapes
in fruit cocktail).
For the most part, this rule only affects wine and grape juice. This becomes a
concern with many fruit drinks or fruit-flavored drinks, which are often
sweetened with grape juice. You may also notice that some baking powders are
not kosher, because baking powder is sometimes made with cream of tartar, a
by-product of wine making. All beer used to be kosher, but this is no longer
the case because fruity beers made with grape products have become more common.
There are a few additional considerations that come up, that you may hear
discussed in more sophisticated discussions of kashrut.
- Bishul Yisroel
- In certain circumstances, a Jew (that is, someone who is required to keep
kosher) must be involved in the preparation of food for it to be kosher. This
rule is discussed in depth under
Food Fit for a
King on the Star-K kosher certification
- Cholov Yisroel
- An ancient rule required that a Jew must be present from the time of
milking to the time of bottling to ensure that the milk actually came from
kosher animals and did not become mixed with milk from non-kosher animals. Milk
that is observed in this way is referred to as Cholov Yisroel, and some people
will consume only Cholov Yisroel dairy products. However, in the United States,
federal law relating to the production of milk is so strict that many Orthodox
sources accept any milk as kosher. You will sometimes see high-level
discussions of kashrut address whether a product is Cholov Yisroel or
non-Cholov Yisroel. See a more complete discussion under
Yisroel: Does a Neshama Good on the
Star-K kosher certification website.
- Most kosher wines in America are made using a process of pasteurization
called mevushal, which addresses some of the kashrut issues related to grape
beverages. See The
Art of Kosher Wine Making on the Star-K
kosher certification website.
The task of keeping kosher is greatly simplified by widespread kashrut
certification. Products that have been certified as kosher are labeled with a
mark called a hekhsher (from the same Hebrew root
as the word "kosher") that ordinarily identifies the rabbi or organization that
certified the product. Approximately 3/4 of all prepackaged foods have some
kind of kosher certification, and most major brands have reliable Orthodox
The process of certification does not involve "blessing" the food; rather, it
involves examining the ingredients used to make the food, examining the process
by which the food is prepared, and periodically inspecting the processing
facilities to make sure that kosher standards are maintained.
These symbols are widely-accepted hekhshers commonly found on products
throughout the United States. These symbols are registered trademarks of kosher
certification organizations, and cannot be placed on a food label without the
organization's permission. Click the symbols to visit the websites of these
organizations. With a little practice, it is very easy to spot these hekhshers
on food labels, usually near the product name, occasionally near the list of
ingredients. There are many other certifications available, of varying degrees
The most controversial certification is the K, a plain letter K found on
products asserted to be kosher. A letter of the alphabet cannot be trademarked,
so any manufacturer can put a K on a product, even without any supervision at
all. For example, Jell-O brand gelatin puts a K on its product, even though
every reliable Orthodox authority agrees that Jell-O is not kosher. On the
other hand, some very reliable rabbis will certify products without having a
trademark to offer, and their certifications will also have only a "K." Most
other kosher certification marks are trademarked and cannot legally be used
without the permission of the certifying organization. The certifying
organization assures you that the product is kosher according to their
standards, but standards vary.
It is becoming increasingly common for kosher certifying organizations to
indicate whether the product is fleishik (meat), milchik (dairy) or pareve
(neutral). If the product is dairy, it will frequently have a D or the word
Dairy next to the kashrut symbol. If it is meat, the word Meat may appear near
the symbol (usually not an M, because that might be confused with "milchik").
If it is pareve, the word Pareve (or Parev) may appear near the symbol (Not a
P! That means kosher for Passover!). If no such
clarification appears, you should read the ingredient list carefully to
determine whether the product is meat, dairy or pareve.
Kosher certification organizations charge manufacturers a fee for kosher
certification. This fee covers the expenses of researching the ingredients in
the product and inspecting the facilities used to manufacture the product.
There are some who have complained that these certification costs increase the
cost of the products to non-Jewish, non-kosher consumers; however, the actual
cost of such certification is so small relative to the overall cost of
production that most manufacturers cannot even calculate it. The cost is more
than justified by the increase in sales it produces: although observant Jews
are only a small fragment of the marketplace, kosher certification is also a
useful (though not complete) point of reference for many Muslims, Seventh Day
Adventists and vegetarians. In addition, many people prefer kosher products
because they believe them to be cleaner, healthier or better than non-kosher
products. It is worth noting that kosher certifiers are not the only
organizations that charge for the privilege of displaying their on a product:
some charitable organizations allow manufacturers to display their logo in
exchange for a donation, but unlike kosher certifiers, those charities do not
perform any service in exchange for that payment.
Do All Jews Keep Kosher?
According to the 2000 National Jewish Population Survey (NJPS), 21% of American
Jews report that they keep kosher in the home. This includes the vast majority
of people who identify themselves as Orthodox,
as well as many Conservative and
Reconstructionist Jews and some
Part of that 21% keeps kosher at home, but eat non-kosher food out of the home
to one degree or another. Some will eat cooked food in a restaurant or a
non-kosher home, as long as the meal is either vegetarian or uses only kosher
meat and no dairy products. Some will eat non-kosher meat in restaurants, but
only if the meat comes from a kosher animal and is not served with dairy
products. Some will go... dare I say? ... whole hog and eat bacon cheeseburgers
out of the home while keeping a strictly kosher household.
Even within the home, standards of kashrut that people employ vary. The
strictest people will eat only foods that have reliable Orthodox
kosher certification, eating only glatt-kosher
certified meats and specially certified dairy products. They will not eat
cooked food in a restaurant unless the restaurant has reliable Orthodox
certification, and they are unlikely to accept an invitation to dinner from
anyone who is not known to share their high standards. Others are more lenient,
accepting less reliable certifications without question or "ingredients
reading," accepting grocery store items that have no certification but do not
contain any identifiably non-kosher ingredients.
As rabbi/humorist Jack Moline noted, "Everyone who keeps kosher will tell you
that his version is the only correct version. Everyone else is either a fanatic
or a heretic." (Growing Up Jewish, 1987). There is a lot of truth in this
humorous observation. I have no doubt that some are calling me a heretic for
even acknowledging the existence of lower standards, because kosher is kosher,
and if you don't live up to my standards then you aren't keeping kosher
You can find more information about kashrut at the websites of major kosher
The Orthodox Union, which is responsible
for "OU" certification, has some excellent information on its website,
including a kosher primer, an explanation of their kosher policy, a
philosophical discussion about "thinking kosher" and a questions and answers
section. (Please note: the "Judaism 101" listed on some of their pages is not
this website and has no connection with this website).
The Star-K Kosher Certification
organization also has an excellent website. The wonderful thing about Star-K
is, they give you an incredible amount of detail about the research that they
put into determining whether a product is kosher. They tell you what products
may be used without kosher certification, and they explain why such products
can or cannot be used without kosher certification, giving complete detail
about the research that went into making their determination. It also has
articles about kashering appliances, and other useful information.
KosherQuest has a searchable database of
kosher products as well as an extensive list of reliable kosher symbols and
other interesting things.
© Copyright 5756-5771 (1995-2011), Tracey R Rich
If you appreciate the many years of work I have put into this site,
show your appreciation by linking to this page, not copying it to your site.
I can't correct my mistakes or add new material if it's on your site. Click Here for more details.