Kashrut (Keeping Kosher)

All laws related to Kashrut belong to the ‘laws of obedience’ (which are laws that require us to do something). The Hebrew word ‘kasher’ means ‘fit to be used according to Jewish law’. It means that a given product is permitted and acceptable. Laws about foods are so important that one of the first commandments ever given to human beings concerned food: Adam and Eve were told not to eat the fruit of the Tree of Life.

The laws and principles of kashrut are given to us in the Five Books of Moses and are classified as ‘statutes’ – we are commanded to uphold the laws although we are not given a reason for it. Some rabbis maintain that by keeping kosher from an early age, children learn discipline, distinguishing between what is allowed and what is not. Other rabbis have come up with ideas such as if you do not eat kosher food, your spiritual capacity is dramatically reduced. They believe that keeping kosher is good for the soul, just as eating a healthy diet is good for the body.



The Torah says that we are only allowed to meat from certain animals and there are very strict laws concerning how the animal is slaughtered and what happens afterwards.

As for red meat, the animals must have cloven hooves and chew the cud. Such animals include goats, sheep, cattle and deer. Types of animals which comply with the requirements are known as ‘kosher species’.

Cows and sheep are the most commonly consumed kosher species of land animals
Cows and sheep are the most commonly consumed kosher species of land animals

In addition to the requirement that meat is kosher only if it comes from a kosher species, there is also a requirement for proper ritual slaughter (called shechita) of the animal (this shechita applies only for land animals and birds, not for fish). It is forbidden to eat an animal which died on their own e.g. from disease or injury – such animals are called neveila. After ritual slaughter, the carcass of the animal is examined internally and is passed for consumption only if found to be healthy – any animal found to have been diseased or injured is classified as treif and not permitted to be eaten.

We are not allowed to eat certain parts of the animal once it has been killed. These parts are:

  • the blood
  • certain types of fat called helev (this is the fat found around the internal organs and is particularly dense. In English it is known as suet.)
  • the sciatic nerve called the gid hanashe. The gid hanashe is very difficult to remove. In most English-speaking countries, the hindquarters of animals (through which the sciatic nerve runs) are sold on the non-kosher market

Performing Shechitah

Kosher meat and poultry must be prepared by the method of shechita – a swift cut by a razor-sharp knife – which Jews believe to be the most painless means of slaughtering the animal. The knife used must be very sharp, and free from any notches which might tear the flesh. The man who performs the shechita, a shochet, has received permission to act as a ritual slaughterer. In Israel, in addition to the shochet, there is another person who is responsible for removing the fat (helev) and gid hanashe. Both the shochet and this person are subject to checks by a rabbi who is in charge of meat.

After shechita, the animal must undergo a thorough inspection (bedikah) to check if it has any damage which according to Jewish law would make it unkosher. The lungs of cattle and intestines of chickens are always checked.

This is where the term ‘glatt kosher’ comes in. In the case of cattle, if the lung is free of any damage, it is termed ‘glatt’ – smooth. If there is minor damage, the animal may still be kosher – though not ‘glatt’ – depending on the level of the damage. In everyday parlance the term ‘glatt kosher’ has also come to mean ‘strictly kosher’ although this is not the technical meaning of the term.

Porging (Nikkur)

This is the process of removing those parts of the animal that are not kosher: fats and the sciatic vein. This is very difficult in the hindquarters of animals and that is why often we do not find these parts available for sale. Instead of nikkur, these cuts of meat are often discarded or sold on the non-kosher market (where there are no restrictions on eating them).

Soaking and salting (the common method of ‘kashering’ or drawing out the blood from meat)

After shechitah, bedikah, and nikkur (if appropriate), the meat is soaked and salted to ensure that any blood is removed from it before consumption (there is a strict Torah prohibition on the consumption of blood). This soaking and salting must take place within 3 days of slaughter, as otherwise it is considered the blood has become too congealed and cannot be successfully removed by this method.

The meat is rinsed off under water, then left to soak for 30 minutes in lukewarm water. This opens up the pores of the meat so that any blood may more easily be absorbed out of it.

After soaking for half an hour, the meat should be washed carefully and allowed to dry for a little while, but not completely or the salt will stick to it. The meat is now salted on all sides so as to draw any remaining blood out of the meat. A medium grade of salt is used – not fine table salt which would dissolve, and not coarse salt crystals. The meat must be left covered in salt for an hour on a sloped board so that the blood can drain off into a sink or container. After an hour, we rinse the meat three times to remove the salt and blood. This soaking and salting process is known as ‘kashering’ since it draws out the meat from the blood and once it is completed the meat is considered kosher and fit for completion. Utensils used during the kashering process, having been used with food which is not yet fully kosher, may not be used afterwards with kosher food.


Some meat cannot be kashered by soaking and salting. There are two categories of such meat:

  • meat which has aged more than 3 days since it was slaughtered. It is considered that the blood is now so congealed that it cannot be successfully drawn out by soaking and salting.
  • liver, which is an internal organ particularly dense in blood.

These meats may be kashered by the alternate process of grilling. As with kashering by soaking and salting, utensils used in this process may not be used with food once it has been kashered.

These days, kosher butcher shops grill liver to kasher it before selling it to customers, thereby alleviating them of the need to do it themselves and have a special set of utensils for this purpose.


We are told in the Torah that we are not allowed to eat blood because blood is the soul and the life force of the animal. That is why if there is blood in an egg, we must throw it away. We are not allowed to eat it. When baking, we should never crack an egg directly into the mixture; we should first crack it into a glass or other clear container to check for blood spots, and only then (once it is found to be free of blood spots) transfer it into the mixture.


The law prohibiting the mixture of meat and milk is stated three times in the Torah, resulting in it being taken particularly seriously. To ensure that accidental mixtures of even traces of these foods are avoided, kosher households have separate sets of utensils for meat and milk. This extends to sinks and dishwashers, pots and pans, cutlery and crockery.

Food that does not have any meat or milk in it is said to be ‘pareve’. This means that the food is neutral and can be eaten with either meat or milk. Examples include fruit and vegetables, eggs, fish and drinks other than milk.

Eating milk after meat

After eating meat, we have to wait a certain amount of time until we are allowed to eat foods containing milk. Customs vary as to how long the waiting period is, but most people wait six hours, whereas people of German Ashkenazi descent are obliged to wait only three hours. This waiting period is required because meat is digested more slowly than other types of food.

Eating meat after milk

When we eat milk products, they are digested much faster than meat products, therefore we don’t need to wait very long. The custom is to wait for half an hour after eating milk to eat meat. We are told to wash our mouths after the milk before we eat meat substances. There is one exception: when we are eating hard cheese, before eating meat we should adopt the same waiting period as between meat and milk. This is because hard cheese (cheese which has aged for at least 6 months), like meat, takes a long time to digest.

Deriving benefit

The prohibition of mixing meat and milk is taken very seriously because of it having been stated three times in the Torah. It is extended to even deriving benefit from a mixture of meat and milk. Thus if a kosher observant Jew for example accidentally mixes meat and milk together, they may not sell it or even give it as a gift to someone who is not Jewish (they might feel gratitude which would be a ‘benefit’); nor may they feed the mixture to their animals.


Another rule of kashrut is not to eat fish and meat together, but for a different reason to that of meat and milk. It is simply that the rabbis, in favour of a healthy lifestyle, believed it would be physically harmful to the body to eat the two together.

It’s perfectly okay to eat meat immediately after fish and vice versa, for example salmon after a cocktail sausage at a reception. But it is the custom to cleanse the palate first by having some bread or a drink. This may explain the reason why many people drink a L’chaim – a toast in whisky, vodka or another strong liquor – after the gefilte fish at the Shabbat table before moving on to the next course.



We are not given specific rules for which birds we are and are not permitted to eat. Instead, there is a long list of forbidden birds given to us in the Torah. These birds are forbidden: eagle, ossifrage, osprey, kite, vultures, bats, storks, ibis, ravens, pelicans, swans, herons, magpies and hoopoes. As a result, birds of prey are considered to be not kosher. Species such as chickens, ducks, turkeys and quail are considered to be kosher.


Trout - a kosher breed of fish with both fins and scales
Trout – a kosher breed of fish with both fins and scales

There are certain rules about which fish are kosher. There is one important rule to remember: a fish is kosher if it has both fins and scales (however, not all types of scale indicate that a fish is kosher – if in doubt, a rabbi should be consulted). Examples of non-kosher fish are all shellfish, eels, shark, and leatherjackets. Fish should be bought only from a kosher certified store, or if it still has the skin attached so that it may be confirmed that it is of a kosher species (although the requirement is for a kosher fish species to have both fins and scales, all species with scales also have fins, whereas some species have fins but no scales).


Milk is kosher only if it comes from a kosher species of animal. Thus, for example, cow or goat milk is kosher, but pig or horse milk is not kosher.

Because of the impossibility of judging if milk is kosher simply by looking at it, the rabbis introduced a rule that milk should be drunk only if it was supervised at the time of milking by someone Jewish who would certify that it was from a kosher species. In modern times some people (especially those who are charedi) still insist on this requirement (milk which complies with it is known as chalav Yisra’el), but others do not in countries such as Australia where there is strict enforcement of food purity laws so that they feel confident that they can rely on the labelling of milk sold in shops to correctly identify it. Chalav Yisra’el milk is available for sale in most cities with a sizeable Jewish population such as Sydney and Melbourne.


Cheese can be kosher only if made from kosher milk i.e. from milk from a kosher species of animal.

There is an additional requirement. Cheese is normally made with rennet, an enzyme which speeds up the setting process. However, rennet is usually obtained from animals’ stomachs, hence it is considered ‘meat’ since it is obtained from the carcasses of dead animals. This is is a problem from a kashrut perspective as:

  • the rennet may have been obtained from a non-kosher species of animal (e.g. a pig), and
  • the rennet is being mixed into cheese, which is a dairy product and therefore may not be consumed with any meat product according to the laws of kashrut.

Accordingly, there is a rule that hard cheese may be considered kosher and consumed only if it is certified as being kosher (the requirement does not extent to soft cheeses which do not require rennet in their manufacture process). This is to ensure that any rennet used is from a non-animal and therefore kosher source (as a general rule, non-kosher rennet is cheaper to buy than kosher rennet, hence there is always a commercial temptation to use non-kosher rennet).


Wine and grape juice likewise must come only from a rabbinically-approved source, but not for the same reason as cheese. Before the Roman exile in 70CE, the Jews were in danger of assimilation. Therefore, they were banned from drinking wine made by a non-Jew (known as ‘yayin nesech’) in order to prevent fraternisation which could eventually lead to intermarriage.

As it happens, non-kosher ingredients often appear in the manufacture of non-Jewish wines, such as bull’s blood for colouring or more commonly, isinglass, a ‘fining’ agent, which comes from a sturgeon – another reason for avoidance.


We are told explicitly in the Torah that we are not to eat any insects whatsoever. Thus, when preparing fruit and vegetables to eat, we need to make very sure that there are no bugs hiding within them.


We are discouraged by the rabbis from eating bread that has not been manufactured in a Jewish place. However, it may be difficult to obtain bread of this nature, therefore, we are allowed to eat commercially produced bread although we should be aware of the following fact: bread usually contains fat, which may be of animal or other origin. There is also the possibility of a glaze being applied to the crust, or of non-kosher fat being used to grease the baking tins; such fat need not appear on the list of ingredients. Furthermore, the bread may be baked in the same ovens as non-kosher bread or cakes; this, too, would render it non-kosher. In practice, no generally-available non-supervised bread is known to be kosher, though health-food shops may stock vegetarian bread.


Many biscuits or cakes are baked in ovens used to bake non-kosher products. Furthermore, the butter or margarine used to bake these items is often not kosher. The fat used to grease the tins or trays may also not be kosher as it may come from animals (again, commercial considerations are relevant; animal fats are generally cheaper to buy than fats from other sources). No indication of this will appear on the ingredient list, so there is no sure way of knowing, unless you buy kosher-certified biscuits or cakes. For these reasons, each item must be considered individually.


These contain fats and emulsifiers which may be of animal origin; even the manufacturers of ‘vegetarian’ margarine cannot always guarantee that the source of their emulsifier is vegetable. Only margarine under rabbinical supervision may be used.

Processed foods

Increasingly, more products carry a kosher label, like the KA (Kashrut Authority) logo. Every ingredient in every product has to go through a thorough inspection to decide whether or not it contains non-kosher substances. Many products such as yoghurts may contain non-kosher substances like gelatine.

Even where the ingredients are fine, the product may still be non-kosher because of other unlisted agents used in its manufacture, such as release agents used to grease the production line. Even when a product is said to be vegetarian, it may have been prepared on a piece of equipment that was previously used for making meat (without there having been sufficient washing in between).

Health Foods

It should be noted that many of these products are natural but nevertheless non-kosher. Products containing pure vegetable oils can be problematic as many oil manufacturers produce animal tallow on the same equipment (this problem is particularly prevalent in Australia). Natural flavours can contain polysorbates, grape derivatives, beaver extracts, etc., all of which are natural but require supervision or are non-kosher. Even if a product is sold in a natural or health food store, it requires supervision as it may well contain questionable ingredients.

Travelling Kosher

For the traveller in Australia, kosher-certified products are available in certain areas of the main cities of Sydney and Melbourne. It is much more difficult to obtain reliably kosher-certified products in areas away from the cities. A traveller who has frozen meals which must be reheated in a non-kosher oven must completely cover the frozen package with two layers of aluminium foil. If a microwave is to be used, the food must also be double wrapped.

When travelling by plane, train or ship, kosher meals should be ordered in advance. These meals are also heated in non-kosher ovens. The employees of the carrier are instructed to heat these meals in the same manner that they were received; totally wrapped in double foil with the caterer’s seal and the Rabbinic certification seal intact. The traveller can ascertain by the intact seals that the dinners have not been tampered with. Any dinner which is not properly sealed should not be eaten. The kosher certification only applies to the food in the sealed package. Any other food (rolls, wines or liqueurs, cheeses, coffee creamers or snacks) served loose by the carrier are not included in the kosher endorsement.

Adapted from articles on www.ou.org and www.kosher.org.uk/what.htm