Why does food need kosher supervision?
Why does food need kosher supervision?

Q: Is one obligated to buy food with kashrut supervision? Why can’t a person rely on the seller or manufacturer who testifies to his products, such as dairy products made from cow’s milk, and are obviously kosher anyway? And various sweets such as chocolate, why do they need kashrut supervision – after all, they’re made from cocoa and sugar and other kosher ingredients? Why worry they contain something prohibited?

Basic Loyalty and Supervision of Merchants

A: As a matter of principle, Jews are credible when it comes to mitzvot, therefore the Torah commanded that every Jew, whether male or female, fulfill the mitzvoth of kashrut himself: slaughter and kasher kosher anumals removing chalavim (fat portions), gid ha’nasheh, and blood, without a Kohen or Chacham supervising him, and separate terumot and ma’asrot (tithes) from his fruits without the supervision of representatives from a Beit Din.

Thus, any Jew who is a guest at another Jew’s home may rely on him and eat his food – assuming that before the meat was prepared he slaughtered the animal according to halakha, that he did not mix meat and milk in his foods, that he made sure there were no insects in them, that he separated terumot and ma’asrot from his fruits, and that challah was taken from his dough-like batter.

Not only that, but according to the mitzvoth of the Torah, even the Kohanim rely on every Jew and eat from the animals they slaughtered, for the Torah commanded Jews to give the zero’ahlechaim, and keyva to the Kohanim to eat. Regarding this, the Chachamim said: “One witness is relied upon in prohibitions,” i.e., that one man may attest to his foods that they are kosher (Rashi Yevamot 88a, s.v. ‘ve’amar’; Chulin 10b, s.v. ‘eid’).

We have also learned that every Jewish man trusts his wife on the matter that she has cleansed herself of the impurity of nida (Tosafot, Gitin 2b, s.v. ‘eid’).

However, this basic trustworthiness depends on two conditions: first, that the person trusted knows how to fulfill the details of the mitzvot. Second, that this person is not known to be someone who disrespects the mitzvah.

However, a merchant who makes money from selling food is judged differently. Just as Beit Din is obligated to supervise that the weights and measurements of merchants are accurate, because without supervision, there is fear their yetzer (temptation) will overcome them (Baba Batra 89a), so too, food merchants must be supervised (Aruch HaShulchan, Y.D. 119:4). Therefore, food products produced in factories must also be supervised, since the factory owners make a living from them.

What Are Food Additives?

Q: Since the law requires factory owners to write the ingredients of each product and fines them if they are found cheating,  this means they already have supervision and the kashrut of each product can be determined by the ingredients contained therein. Why do we need the supervision of a rabbinate on products such as milk and candies, whose preparation does not involve halakhic acts such as shechita and the separating of terumot and ma’asrot?

A: In the modern food industry additives are used, such as emulsifiers, stabilizers, moisturizers, crystallizers, and flavor and color enhancers.

  • In other words, when they want to mix two substances that do not naturally mix, such as water and oil, to produce chocolate or milk delicacies, they use an emulsifier that binds and congeals the two.
  • Since sometimes even after using an emulsifier the two substances tend to separate, they use a stabilizer that keeps them combined.
  • In order to preserve the moisture of products that tend to dry out, they use glazing agents.
  • When they want to prevent food from gelling so it stays nice-looking, soft and flexible, they use anti-caking substances.
  • When they want to make a liquid product thick, such as dairy products made from liquid milk, they use emulsifiers such as gelatin.
  • When they want food products to be preserved for a long time, they use preservatives and antioxidants.
  • Flavor enhancers are also used, whose purpose is to enhance certain flavors and to diminish the tastes of others.

Marking Additives

In many countries of the world, including Israel, food additives are labeled according to the European classification represented by the letter E (Europe), and the ingredients are classified according to their purpose. Each series of hundreds has a special designation: 

  • Ingredients used as edible food coloring are indicated by numbers 100 to 199, i.e., E100 to E199.
  • Preservatives are given the next series, and their labeling is E200 to E299.
  • Acidity regulators and antioxidants are labeled E300 to E399.
  • Thickeners, emulsifiers, and stabilizers are marked E400 to E499.
  • Gelatin is included in this series and is marked E441, and glycerin is marked E422.
  • In the 500-599 series are anti-caking substances and acidity regulators.
  • The series of flavor enhancers is 600-699.
  • The series of 700-799 is antibiotics to prevent bacterial development.
  • 900-999 is a series of glazing agents, gases, sweeteners, and others.

These are the main ingredients used in the food industry.

In practice, every industrial product today has dozens of additives, and their kashrut requires supervision.

The law does not require the labeling of all of them, but only the main ones.

The Kashrut of Food Additives

Almost all food additives are produced abroad, therefore, when they are plant-based, they do not involve halakhic questions, except for substances produced from stamyainum (wine which might have been poured for an idolatrous service). However, when they are produced from animals, they are usually prohibited, because they are produced from impure animals such as pigs, or from pure animals that were not slaughtered according to halakha. Additives noted as being problematic are glycerin, followed by gelatin.


Glycerin is one of the fatty substances in an animal’s body, and its purpose is to preserve energy for times of starvation. It is used in the food industry for emulsion, stabilization, thickening, sweetening, preservation, and other purposes. Its marking is E-422. In large factories around the world, it is produced from impure animals such as pigs, or from pure animals such as calves that have not been slaughtered according to halakha. Today there are plant and synthetic substitutes.

At first, about 150 years ago, glycerin was used for the purpose of thickening and sweetening liqueurs. It was produced by boiling, which did not make it inedible, and consequently, the poskim agreed that its use was prohibited (Darchei Teshuva 103:70; Yismach Levav, Y.D. 24).

With the development of the food industry, glycerin also began to be used as a stabilizer, emulsifier, preservative, and as an anti-crystallization agent and other uses, so that sometimes it is enough to use just a minimal amount of it. In addition, an alternative method of distilling glycerin from fatty acids was developed by mixing caustic soda with fat. At that stage it is toxic and inedible, and afterwards, the glycerin is separated from the caustic soda, and is once again edible.

Some poskim say that since there was a stage in which the glycerin was inedible, its prohibition is void, and after becoming edible again, ‘panim chadashot ba’u l’kan’ (something entirely new), and it is not prohibited. In addition, many times the amount does not reach one-sixtieth, and in any case, is nullified. And it cannot be argued that it has the status of ma’amid (a gelling agent), because quite often its effect on a food product is not as evident as a regular ma’amid (Sridei Aish 2:21).

On the other hand, in the opinion of many poskim, glycerin is not considered a new product, since it is only separated from the fatty acids that were attached to it. In addition, it itself is edible, for only the addition of caustic soda made it inedible, and afterwards, when removed, the glycerin remains edible as it was initially. Therefore, when it is the sole ma’amid, it is prohibited, and even when it is not the only ma’amid, it is forbidden to be mixed-in deliberately, and if it was mixed-in, l’chatchila (ideally), it is forbidden to eat it (Minchat Yitzchak 5:5; Mishneh Halachot 9: 154).

Since the reasoning of the machmirim (strict poskim) is convincing, and is the opinion of the majority of poskim, this is the practical instruction, that glycerin should be produced from pure animals that have been slaughtered according to halakha, or from vegetable oil.


Gelatin is produced from the collagen protein found in bones and skins. Its job is to stabilize and gel candy, ice cream, dairy products, and the like. Large factories produce it from impure animals such as pigs, or pure animals such as calves that were not slaughtered according to halakha. In the production process, the bones and skins are soaked in lime to extract liquid and additional substances, and the remains are ground into powder, which is the gelatin.

There are poskim who permit gelatin, since in its production process, the bones and skins lose all their taste to the point where they are no longer edible, and since panim chadashot ba’u l’kan, it is not prohibited. And if it is extracted from the hard part of the bones, there is another reason to permit it, because this part of the bone is never considered edible, and consequently, from the start, the prohibition does not apply to it (Achiezer 3:33; Har Tzvi, Y.D. 83; Yebiah Omer, Vol. 8, Y.D. 11).

On the other hand, there are poskim who prohibit gelatin, because the production of gelatin is not considered to be the creation of anything new, but merely the separation of collagen from the other substances, and consequently, the Torah prohibition applicable to the bones and skins of impure animals and nevilot remains on the gelatin separated from them. It is not batel be’shishim, since it has the din of a ma’amid that is not batel be’shishim (Iggrot Moshe, Y.D. 2:23, 27; Minchat Yitzchak 5: 5).

In practice, those who want to be maykel (lenient) are permitted since the controversy is in Divrei Chachamim (rabbinical), for in practice, gelatin has no taste, rather, it is a ma’amid and stabilizer, and the general rule that a ma’amid aino batel afilu  b’elef (a ma’amid is not nullified even in a thousand) is derived from Divrei Chachamim.

Nevertheless, l’chatchila (ideally), it is proper to take into consideration the opinion of the machmirim (stringent poskim), in particular, today, when it is possible to obtain gelatin produced from kosher animals or to use alternative coagulants.

Every Product Requires Kashrut Certification
In practice, consumers are not familiar with all food additives (only a few of which have been mentioned in this column). They cannot know what is produced from prohibited animals, and what is produced from plants or synthetic materials, which food additive is considered a ma’amid which prohibits the food, and which additive is not considered a ma’amid.

Therefore, responsible kashrut supervision of all industrial food products is required, and without such supervision, no industrial food may be eaten. Since in certain matters there are controversies, there are different levels of kashrut supervision. In regular kashrut, the opinion of individual poskim and sofakot d’Rabanan (uncertainty in rabbinical ordinance) are not taken into consideration, and kashrut is given according to ikar ha’halakha (the principal halakha), and there are kashrut organizations which take into consideration the approaches of all the machmirim, and give kashrut le’mehadrin.

As I wrote this column, I regretfully heard that Rabbi Oren Ben Zahara Duvdevani shlita, who contributed from his knowledge and experience to the inquiries presented in this column, is ill. May Hashem send him a complete recovery.

This article appears in the ‘Besheva’ newspaper and was translated from Hebrew. The original article may found at: https://revivim.yhb.org.il/