Sources and Reasons:
The Prohibition of Eating Worms
The Torah warns through several negative commandments against eating worms, Vayikra, chapter 11, verses 41–44:
“Every creeping creature that creeps upon the earth is an abomination; it shall not be eaten. Whatever goes upon its belly, and whatever goes on all fours, or whatever has many feet, among all creeping creatures that creep upon the earth—you shall not eat them, for they are an abomination. Do not make yourselves abhorrent through any creeping creature that creeps, and do not defile yourselves through them, lest you become defiled by them. For I am Hashem your G-d. You shall sanctify yourselves and be holy, for I am holy; and you shall not defile yourselves through any creeping creature that crawls upon the earth.”
One who eats a water-creeping creature violates four negative commandments; one who eats a land-creeping creature violates five negative commandments; and one who eats a flying-creeping creature violates six negative commandments.
Without doubt, one who eats infested fruit without checking it may violate many more prohibitions than the prohibitions of neveilah and tereifah involved in eating meat without kosher certification. This is because when a person sits down to eat dried fruit, if it is, Heaven forbid, infested, he may consume large quantities of worms, רח”ל.
Why Worms Are Not Nullified by a Majority
Although the Torah prohibitions apply to eating worms on their own, when a person eats them within a mixture, Torah law would seemingly require them to be nullified by a majority. The reason they are not nullified is that a worm is a beriah, an independently whole creature, and a beriah is not nullified by a majority due to its significance as a complete entity.
As ruled by the Shulchan Aruch, Yoreh De’ah, Laws of Mixtures, siman 100, סעיף 1:
A beriah—for example, an ant, a non-kosher bird, the gid hanasheh, a limb from a living animal, an egg containing an embryo, and the like—is not nullified even in one thousand.
However, this applies only when they are whole. If they have been ground up, they no longer bear the status of a beriah and are nullified by a majority.
Must Every Fruit and Food Be Checked for Worms?
The Ran wrote in Chullin 19 that only fruits in which there is a mi’ut hamatzui of worm infestation must be checked, and he also proved this from the words of the Rambam.
This is the wording of the Ran on the Rif, Chullin 19:
What was written concerning dates from a jar that became worm-infested does not appear correct. For if we are dealing with dates known to have become worm-infested, why did he specifically mention dates rather than fruits generally? Rather, it appears that he mentioned dates because infestation is common in them, teaching that since this is common, even though it is a minority, they were concerned for a common minority—just as they were concerned regarding adhesions of the lung. As we say later at the end of the chapter [67a]: A person should not strain beer at night over a vessel, lest an insect separate onto the vessel. There, it is not known that gnats were in the beer, and even if there were gnats, it is not known whether they separated; nevertheless, since it is common, they were concerned. Here too, there is no difference. The Rambam likewise wrote in chapter 3 of Hilchot Ma’achalot Assurot: Therefore, all types of fruit that commonly become worm-infested while attached [to the tree] may not be eaten until they are checked.
From the above, we learn that anything with a percentage of worm infestation, even if it is only a minority, must be entirely checked for worms. However, if there is not even a common minority of infestation, it need not be checked.
So too, the Shulchan Aruch rules in practice, Yoreh De’ah, siman 84, סעיף 8:
All types of fruit that commonly become worm-infested while attached [to the tree] may not be eaten until the inside of the fruit is checked, lest it contain a worm.
What Is Considered a Common Minority?
Regarding the question of what constitutes a mi’ut hamatzui, we find several opinions among the poskim.
The Rivash, in responsum siman 191, regarding a non-kosher bird and the inspection for lung adhesions, maintains that the threshold of a common minority is close to half. That is, between 0% and 50%, it is closer to half—namely, more than 25%.
However, the Mishkenot Yaakov, siman 17, maintains that the threshold of a common minority is even lower, namely ten percent. HaGaon Rabbi Shlomo Zalman Auerbach zt”l wrote that it is proper to be stringent in accordance with this threshold of common minority stated by the Mishkenot Yaakov. His words are cited in Bedikat HaMazon KaHalachah (p. 181).
Moreover, in Shevet HaLevi, vol. 4, siman 81, in his letter to HaGaon Rabbi Moshe Shaul Klein shlit”a, it is written that one should be stringent even below ten percent, considering it a common minority. This is also the view of HaGaon Rabbi Yosef Shalom Elyashiv zt”l, who held that even less than 10 percent should be considered a common minority, namely between 5% and 7%.
In practice, the custom is to be lenient that where the rate is below ten percent, it is not considered a common minority and does not require checking.
Fruits Presumed to Have a Common Minority of Infestation—and Therefore Require Checking
Carob, raspberries, fresh or dried figs, strawberries, raisins, raspberries, mulberries, figs, unwrapped fruit leather, and similar items are fruits presumed to be infested at least at the rate of a common minority. They therefore require a sample inspection to ascertain that this type from this bag before us is not infested.
Fruits Presumed Clean, Without a Common Minority of Worm Infestation —and Therefore Do Not Require Checking
Fresh pears without signs of penetration, pineapple, oranges, bananas, peanuts in their shells, or peanuts that have not been stored for a long period; candied pecans, chestnuts that have not been stored for a long period, grapes, papaya, fruit leather that is hermetically packaged in a bag after production, fresh dates, and apples without signs of penetration.
Cashew Nuts—Must They Be Opened One by One to Check That They Contain No Worms?
Regarding whether cashew nuts require checking, as far as we know, there is a common minority of cashews infested with worms, particularly lower-quality cashews.
Therefore, a sample inspection is required to ascertain that the variety before us contains no worms. If no worms are found after checking approximately ten percent, the remainder may be eaten without checking.
Of course, if there are signs of penetration or gnawing, the marked cashew must be opened to check that it contains no worm or insect. It is important to note that crumb-like traces within a cashew do not indicate infestation; rather, they are fragments of the shell.
If the sample inspection does reveal an infestation rate exceeding ten percent, all of them must be opened one by one to ensure that they contain no worms.
This response was translated automatically from Hebrew and has not yet been reviewed by a person. Therefore, it may contain inaccuracies and should not be considered a definitive reference.
