There are two different issues here:
(1) Can Muslims eat Kosher.
(2) Can Jews eat Halal?
This is answered on the basis that the Jews or Muslims are FOLLOWINGtheir religious dietary laws to the letter.
Obviously, Jews and Muslims are physically capable of ingesting food products prepared according to the other’s dietary requirements, so the question is really about the law.
(1) Can Muslims eat Kosher.
Most Muslims feel that kosher food is much closer to halal and can be acceptable as compared to non-kosher and non-halal certified products. In general, Jewish dietary restrictions are more rigorous than Islamic ones, so this is why kosher is usually acceptable. There are two restrictions and issues, though.
Kahrut permits alcohol while Islamic Dietary Laws forbid it. As a result, items cooked, prepared or marinated with alcohol, may be completely kosher, but are haram because they include alcohol.
Concerning Meat (land animals and birds)
There are some debates among Muslims as to whether Jewish blessings during the slaughter of an animal is sufficient to qualify as tasmiyah (تسمية) (blessing God in an Islamic context during slaughter). The majority opinion is that since Jews bless the same God as the Muslims for the same purpose, the Jewish blessings count as tasmiyah. There is a minority opinion that the failure by Jewish butchers to say specifically “Bismillah ar-Rahman ar-Rahim” (بسماللهالرحمنالرحيم) when slaughtering an animal and/or to not bless every single animal, as opposed to entire queues of animals, is sufficient to bar the consumption of kosher meat. This arises primarily as an issue in the Hanafi school of Sunni Islam. No other school has an issue here. There is no other issue for a Muslim eating kosher meat.
In Sunni and Ibadi Islam, there are no restrictions as regards to seafood, so kosher fishes are acceptable. (Non-kosher shellfish and mollusks would also be acceptable for the Muslim.) In some versions of Shiite Islam, only kosher fishes are acceptable for Muslims and Shiite scholars specifically refer to the Jewish law in this regard. The argument is that what God has forbidden remains forbidden. However, many Shiites disregard this ruling and eat shellfish and mollusks as well.
(2) Can Jews eat Halal?
The process for kosher slaughter of meat products has many requirements that halal slaughter or Zabiha (ذبيحة) does not. Accordingly, a Jew who keeps kosher will not eat halal meat.
Concerning Vegetarian Dishes
While it would appear that a halal vegetarian or vegan restaurant (that serves no egg, fish, or meat products) would be satisfactory, the laws of Kashrut would prevent consuming the food here as well. There are a number of issues that could arise:
- Spices are often prepared from living creatures, which are themselves not kosher. A perfect example is the Indonesian spice/sauce called sambal which uses crushed shrimp in its creation.
- Often times a kitchen has not been properly checked to make sure that there are absolutely no non-kosher items.
- Vegetables may not be adequately cleaned to remove all of the bugs that are cultivated along with the vegetables.
- Under Kashrut, cheeses need to be produced without animal rennet, which is not required in Halal. ( animal rennet used has to be halal slaughtered as well to be halal )
- Some Jews follow a Rabbinical command that cooked foods must be prepared by a Kosher Jew.
What is Zabiha
Zabiha is the Arabic term for the Islamic method of slaughter, derived from the Quran and Sunnah. A brief outline of the zabiha method is as follows:
Zabiha slaughter is believed to cause the least amount of pain to animals. It is important to perform the slaughter with respect and compassion. The slaughter is to be performed by an adult of sound mind, who may be Muslim, Jewish or Christian (People of the Book). Using a sharp knife, a swift, deep incision is made into the neck, cutting the jugular vein while reciting the Takbeer, i.e. Allah o Akbar (God is the Greatest). After exsanguination, all the blood is allowed to drain from the animal’s body. Thereafter, the meat may be cut as required.
Islamic dietary laws give a detailed account of the animals (along with birds, insects etc) that are permissible for Muslims to eat. All such animals are halal, the Arabic word meaning lawful. Anything unlawful is known as haraam.
Exceptions may be made where haraam can be consumed in a life threatening situation when halal is not available, but just enough so that the person can survive and be able to reach to a point where halal may be obtained. This is known as the law of necessity.
It is important to note the difference between halal and zabiha. Halal animals are the ones that Muslims are allowed to eat. However, all halal animals (except aquatic animals) must be slaughtered in the method prescribed, i.e. zabiha, before they are considered suitable for consumption by Muslims.
It is easy to get confused as ‘halal’ has become the colloquial word for zabiha today.
What is kosher?
Kosher (derived from the Hebrew kashur, meaning fit) is the English term for food which is prepared in accordance with Jewish laws. Kashrut is the body of Jewish dietary laws, and sechita is the method of slaughter according to these laws. Kashrut is much stricter than Islamic dietary laws in the animals that may be eaten and in the rules of slaughter. There are very detailed requirements of the animal (it should have split hooves and chew its cud), place of slaughter, shochet (the ritual slaughterer), the knife to be used and so on.
What about Christian dietary laws?
Most Christians today do not follow the dietary laws of the Old Testament. Allah has clearly stated that Muslims may eat of what has been made lawful to Christians. But since most Christians consider these laws to be redundant, I don’t think this argument can be used by Muslims to eat everything that Christians eat. Pigs, for example, are strictly unlawful in Islam. Following this argument would mean that Muslims are allowed to eat absolutely everything, which they clearly are not.