In listing the laws of which species may be eaten and which may not, the Torah (Vayikra 11:41), prohibits eating insects. The practical application of this prohibition does not focus on those who desire to eat insects, but rather on eating food items that may contain insects. This week's issue will discuss the parameters of what foods require inspection for insects. [The article will not attempt to apply these discussions to specific foods. Please consult your local kashrut organization for specific guidelines regarding which foods require inspection.]

The Visibility of the Insect
Insects, by their nature, are difficult to spot. This is because of a combination of two factors. First, insects are small. Second, insects are able to hide themselves either through camouflage or by entering small crevices in the food. The challenge of finding these insects presents us with two questions: Is there a minimum size that the insect must be in order for it to be considered prohibited, and what is the status of insects that are hidden so well that they are very difficult to spot?

In dealing with the question of the minimum size of the insect, R. Yechiel M. Epstein, Aruch HaShulchan, Yoreh De'ah 84:36, writes that any creature that is not visible to the naked eye is not prohibited. While R. Epstein's principle eliminates all microscopic organisms from this discussion, there is still a grey area. There are certain insects that are visible to the naked eye, but are too small to be discernable as insects without magnification. They appear as very small dots to the naked eye. This issue is addressed by R. Shlomo Z. Auerbach (cited in Shemirat Shabbat Kehilchata, ch.3, note 105). R. Auerbach was originally of the opinion that in order for an insect to be prohibited one must be able to see the actual movement of the insect with the naked eye. However, R. Auerbach retracted his position when he heard that Chazon Ish was stringent on the matter. [See also, Darkei Teshuva 84:45, for a similar discussion.]

Regarding insects that are hidden, the discussion centers on a different issue. There is a halachic concept of mixtures (ta'arovet), and depending on the type of mixture, there are different standards of nullification. Tosafot, Chullin 95a, s.v. Sfeko, note that if the prohibited item is recognizable within the mixture, it is not considered part of the mixture and therefore not subject to the rules of nullification. For example, if someone were to spot an insect on the surface of a food item and eat that food item, it is tantamount to eating the insect by itself. There are certain instances where the prohibited item is not recognizable per se, but is easily removable through a certain process. For example, many times an insect can be removed from a food by washing the food a certain way. Should the insects in that food be considered part of the food or a separate entity?

This issue is addressed by Rama, Yoreh De'ah 98:4, in the context of a different discussion. Rama rules that if prohibited fat (chelev) falls into a mixture such that the fat represents less than one-sixtieth of the mixture, the fat should technically be considered nullified and the mixture should be permissible. Nevertheless, Rama rules that one must attempt to remove the fat by pouring cold water into the mixture and causing the fat to congeal. Rama considers a prohibited item that is removable through a process to be a distinct item and not part of the mixture.

There is a dispute regarding the nature of Rama's ruling. The source for Rama's ruling is a comment of Issur V'Heter HeAroch 23:9, which implies that the requirement to cause the fat to congeal is a rabbinic stringency and failure to remove the fat does not render the mixture prohibited. For this reason, R. Yonatan Eibeschitz, K'reiti U'Pleiti, 98:6, rules that if the process of removing the fat will ruin the food, one is not required to do so. However, P'ri Megadim, M.Z. 98:7, disagrees and maintains that if the fat is removable it is as if it is recognizable and is not considered part of the mixture. Therefore, failure to remove the fat renders the item non-kosher.

According to P'ri Megadim, there is a potential biblical prohibition to eat a food item that contains insects that are removable through a washing process. According to R. Eibeschitz, the obligation to perform this washing process is rabbinic in nature.

Nullification
Based on the previous discussion, it is arguable that there are certain instances where nullification of the insects is a possibility. According to P'ri Megadim, it is applicable in cases where there is no possibility of removing the insects. According to R. Eibeschitz, it is even applicable in cases where the insects are removable but only through a process that would ruin the food. However, the Gemara, Chullin 99b, presents a major limitation to the nullification of insects. The Gemara states that any whole creature cannot be nullified in a mixture. Therefore, Shulchan Aruch, Yoreh De'ah 100:3, rules that if there is an insect in a mixture and one cannot find the insect in order to remove it, the entire mixture is prohibited.

The rule that a whole creature is not nullified only applies if the creature is intact. If the insect is not intact, the regular rules of nullification can be applied. This will generally be accomplished when a food item is cooked or baked. Therefore, Shulchan Aruch, Yoreh De'ah 84:9, rules that if one cooked a food item that was not checked for insects, one may eat that food item. [It is clear from Rashba, Torat HaBayit 3:4, who is the source of Shulchan Aruch's ruling, that this only applies if there is a doubt whether there is an actual insect in the mixture.]

Shulchan Aruch's leniency is limited to a situation where one already cooked the food. He does not allow cooking the item in place of inspecting the food for insects. Nevertheless, R. Shlomo Z. Auerbach, Minchat Shlomo Tinyana no. 63, rules that if one is preparing food for many people, and it is very difficult to check each individual piece, one may cook the item after a proper wash was performed. This wash must be thorough enough that there is a good chance that the wash itself removed the insects.

Level of Infestation
Many food items that are subject to infestation do not necessarily contain insects in every piece of food. Through experimentation (formal and informal), certain statistics are available regarding the infestation level of food items both before and after washing the food. Is there a level of infestation that is tolerable and one may eat the food item without any further inspection?

There is a concept of following the statistical majority (rov), which dictates that if from a statistical perspective, majority of the instances do not entail a prohibition, one should not be concerned with the minority. However, the rabbis instituted that one should be concerned for the minority if the minority occurs commonly. This is known as miut hamatzui. [The concept is mentioned by Tosafot, Avodah Zarah 40b, s.v. Kol based on the Gemara, Yevamot 121a.] If the minority is a miut hamatzui, one must check for the existence of the prohibition

R. Ya'akov of Karlin, Mishkenot Ya'akov, Yoreh De'ah, no. 17, suggests that if the prohibited item occurs 10% of the time, one must check to see if the prohibition occurred. R. Shmuel Vosner, Shevet HaLevi 4:81, posits that miut hamatzui is not a function of a specific statistic. Rather, any situation where there is a known minority in all locations and all situations, one must check for the minority.

Assuming that one would permit eating an item whose infestation level is less than 10%, one must still determine the size of the sample in which one measures the 10%. R. Yosef S. Elyashiv (cited in Bedikat HaMazon Kehalacha ch.4 note 4) rules that the infestation level is determined by the amount of food that is being served at that particular time. If one is serving many people, one must check for insects until the there is less than 10% chance that there is one insect in the entire stock. R. Shlomo Z. Auerbach, Minchat Shlomo Tinyana no. 63, assumes a similar position. R. Hershel Schachter (cited in Madrich Kashrut pg. 107) assumes a more lenient position. According to R. Schachter, as long as there is less than a 10% chance that there is an insect in a given serving, there is no requirement for further inspection.