Is It Permissible to Eat Any Lettuce?

Presumably, none of us intentionally eats insects for pleasure. In practice, many of us eat insects without knowing it. This happened to me at the Shabbat celebration following my wedding, somewhere back in December 2002. The extended family sat around the table on Friday evening after the meal. Some of the guests were chatting while others sang Shabbat songs. I was mainly occupied with munching on cashew nuts placed in a dish in front of me. Later, additional family members arrived, including a rabbi who serves as a yeshiva head, who sat beside me.

"You know, uncle, there are worms in cashews," he cautiously and caringly remarked when he saw me putting whole nuts into my mouth. "Worms in cashews?!" I asked in disbelief, "How do they even get inside? They're sealed." My rabbi-uncle smiled. "That's just it—when you don't open them, you don't see," he answered. "You should open each cashew before putting it in your mouth; eating worms is a severe Torah prohibition."

I remember thinking, traditional and enlightened as I considered myself, that here we go again with religious people and their new inventions.

But still, a respected rabbi, a yeshiva head, was sitting next to me, and I felt uncomfortable continuing to munch cashews without playing along with the inspection game. Well, I'm prepared to swear to you that inside the first cashew I opened lay a thin, gray, disgusting worm. Naturally, since then I haven't eaten a single cashew in my life without checking (and the same goes for dates, figs, etc.), but that small arrogance taught me an important lesson for the future and in general.

Most of the stringency against insect infestation is found in leafy vegetables—lettuce, cabbage, parsley, and so on. It turns out there's an entire industry of kosher certifications around these vegetables, and even if you buy vegetables not grown using the Gush Katif method, you must meticulously prepare them in case a worm is found. Why is there such stringency regarding eating insects, and how should we avoid eating them?

"In the Torah, there are five prohibitions—Torah-level prohibitions—against eating insects," Rabbi Pinchas Badush clarifies the halakhic background. "Since vegetables today are grown without disconnected growing mediums, they contain insects. Our obligation is to make every effort to avoid this. Therefore, there were times when eating leaves required disinfection in various ways, but technological developments allow growing vegetables in disconnected mediums that are many times cleaner."

Rabbi Badush explains that the process is complex, but generally involves growing through air absorption, like a perforated pot. "Insects, which come from the soil, have no access to the vegetable itself," he explains regarding some of the "kosher" growing methods, and clarifies that even here the leaves must be cleaned, albeit in a much simpler manner.

So how is there kosher-certified lettuce in supermarkets, despite it possibly containing insects?
"Even with certification, it states that cleaning is necessary, but here, with special growing methods, we reduce the probability of insects by about 90%. Lettuce grown using the Gush Katif method—there's almost no chance of finding insects after thorough washing."

Rabbi Yitzchak Gabai adds and emphasizes that eating vermin and crawling creatures is more severe than eating pork, as the Torah mentions the prohibition regarding pork only once, while regarding various insects we are warned no less than five times. "'Sanctify yourselves and be holy, for I am holy; and you shall not defile yourselves with any crawling creature that moves upon the earth,'" he quotes from Leviticus chapter 11, explaining that this message repeats itself in various forms throughout the Torah. "The message was duplicated to emphasize that we must take great caution," Rabbi Gabai says. "If we aren't careful—we can easily stumble into eating worms, vermin, and crawling creatures. This includes flying insects like flies, and water creatures like various crustaceans."

Does eating vermin and crawling creatures have spiritual implications, beyond the sin itself?
"Our sages say it dulls the heart and brings an impure spirit upon a person. It's known that the soul is affected by the food one puts in their mouth. The Kabbalists, for instance, wouldn't eat meat except on Shabbat. Meat has something coarse that correspondingly affects the soul. Similarly, insects are the lowest in creation, and therefore greatly affect a person's soul. The book Kaf HaChaim writes that it not only spiritually harms a person, but there are physical diseases caused by eating insects. Eating them clouds the blood, thus creating various physical illnesses."

In the past, there were no greenhouses for growing lettuce, so how did people eat leafy vegetables?
"In the past, food reached our plates shortly after being harvested. Much of the food that arrives today is dried, stored, imported from abroad. Thus, considerable time passes before we eat it. This causes insects to reach the food along the way, and for insects to develop within the food. Therefore, when there's a lengthy process until food reaches a person—there's a prevalence of developing vermin and crawling creatures. Additionally, due to global sharing, many pests from other parts of the world that weren't here in recent years have arrived in the country through other agricultural goods."

Although fruits and vegetables age, farmers spray almost all crops.
"It's important to know something significant—spraying doesn't kill all insects, only those that harm the crop itself. There's the thrips, for example—a very common insect-larva found in corn cobs. They hide between corn kernels. In agricultural literature about spraying, it's not mentioned because thrips don't harm crops. Therefore, farmers don't make any effort to eliminate them. But from a halakhic perspective, it's also forbidden to eat insects that don't harm the fruit.

"In greenhouses operating according to the Gush Katif method, there are various elements that significantly reduce the presence of pests: a very dense net that prevents insects from entering, pest control stickers, supervisors constantly checking that no insects entered, and so on. True, there can be insects even in leafy vegetables from Gush Katif, but in principle, it's much cleaner and controlled."

What about microscopic worms that can't be seen with the naked eye?
"The rule is that the Torah wasn't given to ministering angels. That is, what's prohibited is what can be seen with the regular eye. A person who tries to check with a regular eye and doesn't find anything—that's perfectly fine. On the other hand, one needs to check against sunlight and not in some dark room, because there are insects visible only in sunlight. In lettuce, for example, you won't see anything in a regular room, but if you look at the leaves against sunlight—suddenly you'll discover insects. Therefore, checking under optimal conditions is necessary.
"Another thing from a more spiritual perspective: as generations progress, there's more proliferation of insects. It's written that in the Temple, not even a fly was in the slaughterhouse. That is, the more elevated a generation is spiritually—the more those lowly creatures distance themselves from humans. But the more a person descends spiritually, the more pests there are."