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Final Installment: The Laws of Worms and Insects in Food


In this final installment of our series on the laws of insects in food, we will explore several important questions and issues: What distinguishes insects that develop in fruit on the tree from those in storage? Are mushrooms considered connected to the ground, despite their tiny roots? What is the blessing for mushrooms? What is the natural habitat of an insect created inside fruit? What is the status of a worm that is removed dead from the fruit? Does a hole in a bean or other legume render it unfit for consumption? Is it permissible to sell infested produce to a non-Jew? Are the anisakis worms in fish permissible? Why does the Torah strictly prohibit eating worms and insects?

These questions and more are addressed in our article this week,.

Worms In Their Natural Habitat

In the previous article, we discussed the laws pertaining to worms created in water, detailing the circumstances under which they are prohibited and those where they are permitted. This week, we focus on insects that develop inside fruits and animal products, including fish, poultry, and meat. We will explore specific laws that, under certain conditions, allow these worms to be consumed.

Worms Created Inside Fruit

We will begin with worms found in fruits. The Gemara (Chulin, end of Chapter 3) elucidates, based on various verses, that the laws differ for worms that have crawled on the ground compared to those that have not, with the latter being permitted. According to halacha (Shulchan Aruch, YD 84:4), a worm created inside a fruit that has been detached from the ground is permissible to consume, provided it remains within its natural environment (as defined below). However, it is ruled (Shulchan Aruch, YD 84:6) that if a worm is created inside a fruit that is still attached to the ground—whether it be a vegetable, grain, legume, or a fruit growing on a tree—that worm is prohibited to eat.

Infested Mushrooms

There is an interesting discussion among the Rishonim regarding mushrooms: are they considered attached to the ground in this context, or not?  Rabbinic authorities established that “shehakol” is the blessing for mushrooms and not “borei pri ha’adama”, because they grow from the air and not from the ground. The Gemara (Berachos 40b) adds that one who vows not to eat fruits of the ground is permitted to eat mushrooms, but one who vows not to eat anything that grows from the ground includes mushrooms in the prohibition. This implies that, in general, mushrooms are not considered ground-grown produce. However, since they do derive some benefit from the ground, when one refers to all ground-grown produce, mushrooms are included as well.

Rabbi Chaim Kanievsky, in Derech Emunah on Shemitah (Chapter 4:1), explains that despite the fact that we can now use magnifying glasses to see the fine roots connecting mushrooms to the ground, halacha is determined only by what is visible to the naked eye. Therefore, mushrooms are not halachically classified as ground-grown produce.

The Rema (YD 84:6) rules that for worm infestation purposes, mushrooms are considered connected to the ground, and insects that grow in mushrooms while on their mushroom beds are considered ground-crawlers, and prohibited.

The Maharshal (Yam Shel Shlomo, Chulin 3:100) notes that he avoided eating mushrooms since he frequently found worms at the bottom of the pot after cooking. Today, it is still common to find worms in mushrooms, especially wild ones. Fresh mushrooms should be checked on a sample basis, with recommended guidelines available in books such as “Bedikas Hamazon” by Rabbi Moshe Vaye. However, canned mushrooms are harder to check, therefore it is advisable to purchase them with a reputable kashrus certification that ensures that only high-quality, insect-free mushrooms are used.

A well-known kashrus supervisor shared his contrasting experiences with mushroom production in China and Europe. When he was invited to supervise a mushroom factory in China, he demonstrated to the factory manager how to identify insects in the mushrooms. The Chinese manager, finding it difficult to see the insects, suggested replacing the rabbi who insists the mushrooms are infested. In France, however, upon showing the manager that his produce was infested, the Frenchman responded, “I don’t know if we will eventually sign a contract with your certification, but I would certainly like to pay for your training on how to identify insect-free mushrooms. In my factory, there will be no insects in the mushrooms.”

The Pri Chadash (YD 84:19) references the Maharshal and emphasized that mushrooms should be avoided due to potential health hazards. The Rambam (Hilchos De’os 4:9) also lists mushrooms among foods that are harmful to the body. While some Amoraim did eat mushrooms, they had the expertise to differentiate between safe and dangerous varieties. The Pri Chadash recounts that in his childhood city in Italy, they would test mushrooms by feeding a small piece to a cat. If the cat reacted negatively or died, the mushroom was deemed poisonous; if it survived, the mushroom was considered safe to eat. He concluded with a strong recommendation: “One who values his life should avoid them.”

Today, commercial mushrooms do not pose the same risks. However, anyone picking wild mushrooms must exercise caution (in addition to infestation concerns) unless they are an expert at distinguishing between poisonous and edible varieties, as advised by the Pri Chadash. Incidents still occur where individuals mistakenly identify poisonous mushrooms as safe. Regardless, the Rambam’s opinion remains that mushrooms are not a highly recommended food.

A Worm’s Natural Environment

As we discussed in the previous article, the Torah prohibits consuming a water creature that leaves its natural habitat. Similarly, although the Torah permits a worm created inside a food item detached from the ground, it becomes forbidden once it leaves its natural environment. However, the Gemara expresses several uncertainties regarding the exact definition of a worm’s natural environment. Due to these ambiguities, the Gemara remains uncertain about many specific cases. Consequently, it is ruled (Shulchan Aruch, YD 84:4) that in cases of doubt regarding Torah prohibitions, we must adopt a stringent approach.

Therefore, a worm that moved from one fruit to another, even without passing through the air; or one that moved inside the same fruit from one part to another (e.g., from the flesh to the seed, and on the seed), is forbidden to eat. Similarly, a worm that exits the fruit, even if it does not touch the ground, and then returns to the fruit in which it was created, becomes forbidden.

There is an interesting dispute regarding a worm that partially exits the fruit and then returns. For example, a worm born inside an apple that burrows a hole, sticks its head out, and then pulls its head back into the apple. The Pri Chadash (YD 84:10) forbids the worm, while Rabbi Yonoson Eibeschitz (Plesi, Footnote 3; Kresi, Footnote 7) permits it. The disagreement stems from the Pri Chadash’s view that a worm becomes forbidden once it starts crawling, even partially. Conversely, Rabbi Yonoson Eibeschitz maintains that the Torah permits the worm as long as it remains within its natural habitat, and as long as it has not entirely left it, eating it is permitted.


Additionally, most poskim maintain that, unlike water creatures, where the inside of the container holding the water is considered its natural environment, for land creatures, every movement from the spot where it was born is considered a change of habitat. For instance, once a worm born in a container full of flour crawls from one grain of flour to the next it becomes forbidden.

Dead Worms

Another dispute revolves around a worm that died inside a fruit and was removed from it dead. According to the Rambam, the worm is forbidden to eat and is only permitted while still part of the fruit. The Shulchan Aruch (YD 84:4) follows this opinion. However, the Rosh rules that in this case, eating the worm is permitted, and many later authorities (Shach, Footnote 12; Pri Chadash 84:13; Kresi, Footnote 7; Plesi, Footnote 3) agree that the halacha follows the Rosh.

The Pri Chadash, although he believes the halacha follows the Rosh, advises being stringent according to the Rambam. On the other hand, Rabbi Yonoson Eibeschitz explains the reason for leniency in this case: even the Rambam agrees that the prohibition is only Rabbinic. In a Rabbinic dispute between the Rambam and the Rosh, it is possible to be lenient.

This dispute is practically relevant when dealing with products that became infested after being detached, such as various fruits. Thus there is a dispute concerning whole fruits that were cooked in a pot of boiling water where the worms die immediately from the heat, but the fruits might break apart during the cooking process. As a result, the worms can mix into the dish and become difficult to separate.

Why Are Worms in Attached Fruit Forbidden?

Another question is whether the Torah prohibits all creatures in fruit that is attached to the tree, or only if it is able to crawl.

The Shulchan Aruch (YD 84:6) follows the latter approach, that even an attached fruit is only forbidden if the worm crawled. Therefore, if a worm is created inside an attached fruit, but has no room to move, and only later breaks out of the fruit (e.g., a worm created in a bean or pea where the hole is tight and the skin is close-fitting), the Shulchan Aruch’s opinion is that the worm is permitted to eat. However, the Pri Chadash (Footnote 18) believes that the worm is forbidden immediately because the mere fact that it was created inside an attached fruit renders it forbidden.

In a similar case, the Rema (YD 84:6, following the Shach, Footnote 20) forbids a worm inside an attached fruit or vegetable that is still at the larvae stage, and therefore, has, obviously, not yet begun to crawl. The Taz (Footnote 10) and Shach (Footnote 19-20) rule to be strict not to eat all wormy fruit, even one that has no tunneling, or an unfinished insect that cannot crawl. However, if this sort of fruit fell into the dish, it does not render the dish forbidden. By contrast, the Pri Chadash believes that even b’dieved the fruit is forbidden.

Beans with a Hole

Another dispute between the Shulchan Aruch and the Rema concerns fruits with holes, such as beans that were known to be worm-free when picked or beans that sat more than twelve months after picking, which now exhibit worm holes. If it is known that the worms were created inside the bean and did not come from outside, the Shulchan Aruch permits using such beans. However, the Rema forbids them, citing concerns that the worms may have exited through the hole and then returned inside.

Selling Infested Produce to a Non-Jew

A grocery store owner discovers that some of his merchandise, such as bags of rice or legumes, has become infested. What can he do with it? Selling these products to a Jew is forbidden, and selling them to a non-Jew is permitted only if there is no concern that the non-Jew will resell the merchandise to a Jew. Consequently, selling individual packages of rice or legumes to a non-Jew is permitted because it is uncommon for private individuals today to try to sell such quantities. Additionally, the store owner can give single packages of infested goods to a non-Jewish employee, either as part of his wages, as a tip, or as a gift. However, it is prohibited to sell or give the employee an entire pallet of merchandise, as private individuals who receive a pallet could potentially try to find buyers for it (Rema YD 84:5; Shach, Footnote 17).

Similarly, if there is a concern that the non-Jew might incorporate the infested product into food marketed to Jews, such as worm-infested salt, it is forbidden to sell the salt to a non-Jew who produces and sells food containing salt, if there is a possibility he will use the infested salt. For instance, if the non-Jew operates a kosher food business, the kashrus supervisor might fail to check the salt, assuming salt typically does not contain insects (Pri Chadash YD 84:18). However, an infestation-prone product can be sold to a non-Jew, because if the non-Jew resells it to a Jew, the Jew will inspect the product and discover that it is infested (Taz YD 84:9).

Insects in Meat and Fish

We will conclude with a widely discussed halacha: The Anisakis Controversy. The Shulchan Aruch (YD 84:16) rules that insects found within animals or birds, in any part of their bodies, are forbidden. However, insects found inside of fish are different. Those in the fish’s intestines are forbidden since they are assumed to originate from the sea or river, but those found in the flesh of the fish are presumed to have developed there, and are thus permitted. This ruling is particularly relevant to the Anisakis worms, which are frequently found in fish. The arguments revolve around two questions: is there sufficient halachic evidence to prove that the worms originate outside and swarmed in the open sea before entering the fish, or perhaps it was a microscopic organism while in the sea which only became visible once inside a fish. It is important to note that this matter involves a broad range of rabbinic opinions, which we will not delve into at this point.

The Severity of the Prohibition Against Eating Insects

Finally, it is crucial to recall that the Torah imposes a particularly severe prohibition on eating insects, more so than on other forbidden foods. As the Gemara states (Eruvin 28a, Psachim 24a, Makkos 16b): “One who eats a potita receives four lashes, an ant receives five, and a wasp receives six.”

Rashi explains that a potita is a small water insect. Consuming it whole, despite it not being the size of an olive, is prohibited by the Torah because eating an entire creature violates four prohibitions:

  1. (Vayikra 11:43): “You shall not make yourselves abominable with any creeping creature that creeps”…
  2. (ibid.): “…And you shall not defile yourselves with them, that you should become unclean through them.”
  3. (Vayikra 11:11): “And they shall be an abomination for you. You shall not eat of their flesh, and their dead bodies you shall hold in abomination.”
  4. (Devarim 14:10): “But whatever does not have fins and scales, you shall not eat; it is unclean for you.”

Therefore, if one deliberately eats the small water insect after being warned, the court administers four sets of lashes, one for each prohibition.

For ants or any land insect, the Torah lists five prohibitions:

  1. (Vayikra 11:43): “You shall not make yourselves abominable with any creeping creature that creeps”…
  2. (ibid.): “…And you shall not defile yourselves with them, that you should become unclean through them.”
  3. (Vayikra 11:42): “Any [creature] that creeps on its belly, and any [creature] that walks on four [legs] to any [creature] that has many legs, among all creeping creatures that creep on the ground, you shall not eat, for they are an abomination.”
  4. (Vayikra 11:41): “And any creeping creature that creeps on the ground is an abomination; it shall not be eaten.”
  5. (Vayikra 11:44): “For I am the Lord your G-d; sanctify yourselves and be holy, for I am holy. And you shall not defile yourselves with any swarming thing that crawls on the ground.”

For a wasp, which is a flying insect, there are five prohibitions for land insects, plus an additional prohibition for flying insects:

  1. (Devarim 14:19): ” And every flying insect is unclean for you; they may not be eaten.”

The Rambam (Hilchos Ma’achalos Assuros 2:23) presents a slightly different calculation of the prohibitions.

It is important to emphasize that while the Torah stipulates that each prohibition incurs lashes, it is practically almost impossible for a court to implement this punishment, due to the stringent requirements that must be met:

  1. Witnesses: Two witnesses must observe the person committing the offense.
  2. Warning: The witnesses must warn the offender of the specific punishment for the offense.
  3. Acknowledgment: The offender must acknowledge the warning, explicitly stating that he is aware of the consequences but still finds it worthwhile to commit the offense.
  4. Mental Stability: The court must ascertain that the individual is mentally stable and fully aware of the implications of their actions. This is particularly relevant when considering severe punishments such as 234 lashes for eating a flying insect (6 prohibitions x 39 lashes each).

These rigorous criteria ensure that such extreme punishments are rarely, if ever, carried out, reflecting the Torah’s focus on deterrence and moral education rather than punitive measures. The Gemara notes that a court that executed a person even only once in seventy years was considered excessively severe.

Multiple Prohibitions on Eating Insects

Why does the Torah impose numerous prohibitions on eating insects? Why aren’t 39 lashes sufficient to convey the severity of the spiritual harm caused by consuming insects?

The Pri Chadash (YD 84:53) addresses these questions, explaining: “The Torah imposed many prohibitions and lashes for this because infestation is very common in fruits, vegetables, and legumes, making it impossible to avoid transgressing without great diligence. Therefore, the Torah needed to be exceedingly stringent and impose many prohibitions on insects. Thus, everyone will be diligent in avoiding this prohibition.”

Furthermore, the Pri Chadash emphasizes the importance of public awareness: people should encourage those around them and speak about the severity of this prohibition publicly so that all Jews are careful to avoid this violation.

Diligence and Awareness

Through this series, we have explored various laws concerning insects, which are essential for every Jew. To aid in practical observance, it is highly recommended to keep Rabbi Moshe Vaya’s book, “Bedikas HaMazon” in your kitchen. To quote from the book’s review: “This… English edition of the Hebrew bestseller clears up the confusion about insect infestation… and offers practical solutions for making sure that one’s food is bug-free. Geared specifically to English-speaking communities all over the world, it includes both the pertinent halachos… accompanied by hundreds of vivid, full-color photographs…”.


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