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Don’t Let It Bug You

While the indoor farming industry is still in its infancy, Rabbi Daniel Sharratt and others in the world of kosher certification believe it could bring about a real revolution for kosher consumers, whose options are limited when it comes to fresh produce because of infestation issues. Courtesy of Aerofarms/Wilson Gibbons


Innovative farming techniques are producing crops that are cleaner, healthier and best of all, largely bug-free.


“Eat six servings of fruit and vegetables a day!” repeat nutritionists, and our appetite for produce has expanded in response. But consumers don’t just want more produce. They want produce that uses minimal pesticides, is attractive and tasty, and is free of infestation. For the kosher consumer, however, being able to purchase produce that is free of infestation is critical, as the Torah strictly prohibits the consumption of insects.

Fortunately, new solutions for growing insect-free produce are emerging through technological advances. Innovative techniques for growing plants, as well as new surveillance technologies, are now helping farmers produce crops that are cleaner, free of bugs and pesticides, and can be grown anywhere, lessening the distance to markets.

In the Field 

It would seem obvious that traditional farms, which are exposed to the elements, would be the most vulnerable to insect infestation and the vicissitudes of climate. But that isn’t always the case.

“An outdoor field can be completely clean, especially in cold climates,” says OU RC Rabbi Dovid Bistricer, who specializes in produce, among other areas. “Or you can have one section of a field that’s fine, while the rest is infested.” Rabbi Shimon Yoffe, an OU RFR, says he’s seen fields located just a few minutes’ drive from each other where one is infested and the other is not. 

When Rabbi Yoffe goes out to the fields to check produce for infestation, he takes baskets from each field to sample (each field can produce hundreds of pounds of produce). If the sample basket is clean, chances are high the entire field is clean. Rabbi Bistricer worked closely with Dr. Bruce Bukiet, an associate professor of mathematical sciences at the New Jersey Institute of Technology in Newark, who helped the OU devise statistical models to predict with over 90 percent-or-more accuracy whether a field’s harvest of herbs is less than ten percent infested (the halachic limit for acceptability).

Some forms of produce can be industrially washed to effectively clean off bugs, although that technique is generally used with vegetables that are frozen. “Some foods, like raspberries, turn to mush if you wash them,” notes OU RC Rabbi Daniel Sharratt. “The advantage of freezing is that vegetables from faraway places like China last longer.” 

The US government limits the use of pesticides and will even refuse produce from overseas that’s been too heavily sprayed. (Incidentally, the US government’s tolerance rate for insects on US-grown vegetables is “very high,” says Rabbi Yoffe, a lot higher than pesticide allowances.) When chemical solutions to pests are insufficient, natural solutions can save the day. For example, farmers sometimes combat aphid infestation with other insects. Rabbi Yoffe explains that farmers buy “beneficial pests,” such as ladybugs, in packs of 100,000 (the cost runs about $180 for 50,000 ladybugs), which they release over their fields. The little critters gobble the aphids in short order. When they’re done, the ladybugs can be attracted into a cage or washed off the produce. 

Indoor farming can bring about a revolution for the kosher consumer. If it’s done correctly, the vegetables could be grown bug-free and won’t require washing.

Sometimes, even seeds create problems. “You can find insect eggs in seeds,” Rabbi Yoffe says. “That happened about eighteen years ago in fields near the Canadian border with swede midges. It was a huge job to get rid of them.” Some insect eggs are so tiny they’re not a halachic problem—eggs in flour, for example. But if a product made with them is left in a warm place too long—think of a box of pasta in a warm kitchen—they may later hatch into worms (definitely a problem).

Once produce is gathered, cameras are used industrially to check for impurities. Some factories have as many as fifty camera “eyes” surveying the produce rolling down the conveyor belts, searching for anything that looks different from the peas, corn kernels, beans and such, en route for packaging. If the cameras detect anything divergent, such as a pebble or stick, the belt opens up to let the offending piece fall through. But Rabbi Sharratt, who at one point owned and operated a kosher fresh-vegetable company, warns that those cameras are not effective for catching every problem. They may fail, for example, to detect bugs that are the same color as the vegetables.

Hydroponic farming, used in both greenhouses and vertical farms, is great for some crops, like lettuces, and less effective for others (think strawberries). Hydroponic vegetables generally suffer less infestation from aphids and thrips. “The plants sometimes do get flies,” Rabbi Bistricer says, “but they’re easier to see and wash off.” One OU client grows over sixty varieties of microgreens that are so clean no checking is required. There has been discussion as to whether hydroponically grown produce requires the berachah of Ha’adamah or not, since it doesn’t grow in the ground. Rabbi Yisroel Belsky, zt”l, was of the opinion that if the same type of vegetable is commonly grown in the ground, the proper berachah to be recited is Ha’adamah, even when it is grown in an indoor setting. Nevertheless, since there are dissenting views, Rav Belsky thought it was proper to recite the berachot of Ha’adamah and Shehakol first on other food items instead.

Climate Control 

While outdoor farming is subject to variables such as drought, storms, frost, insects and predators, greenhouses—in which plants are grown in pots or raised bedsensure greater control in protecting crops.

While greenhouses are more protected from the elements, and presumably from pests as well, the actual outcome depends on how carefully they’re sealed and on the quality of the soil and seeds. “There can be breaches in a greenhouse’s netting or windows, or bugs in the soil,” Rabbi Bistricer warns. A well-sealed greenhouse would be like one that Rabbi Yoffe visits in North Carolina, with double-zippered plastic doors at the entrance and a basin for dipping one’s feet at the entrance.

A more recent innovation in the world of farming, known as vertical or indoor farming, entails growing crops hydroponically (in nutrient-enriched water) or aeroponically (in a growth cloth substance and nourished with mist) in indoor structures with the plants placed on shelves under artificial LED lighting. Plants are stacked in vertical rows that sometimes reach twenty or thirty feet in height. Because vertical farms rely on technology to optimize growing conditions, they can be built almost anywhere—“even in a Manhattan basement,” Rabbi Sharratt says. While such farms are very expensive to build, they may be the wave of the future.

How does an indoor farm differ from a greenhouse? “Greenhouses use natural sunlight, while other indoor farming techniques don’t,” Rabbi Sharratt explains. “Indoor farms use an artificial lighting system and manipulate climate, temperature, humidity and even carbon dioxide levels.” Through scanners and artificial intelligence, growers have learned they can control indoor conditions to influence the growth process. “Based on the nutrients the growers give the plants, they can affect the taste of the product—more sweet, more bitter,” says Rabbi Sharratt. “If you hold back on water, making the plant ‘thirsty,’ some will flower faster, which benefits the growers of edible flowers.”

Interestingly, the indoor farming industry expanded when cannabis was legalized; recreational marijuana is so lucrative that much money was poured into research and development of indoor farming to produce it.

Rabbi Sharratt points out that indoor farms reduce water use by 90 percent, which in California, with its frequent droughts, is critical. About 90 percent of the lettuce in the US is produced in Salinas, California, but being able to produce it more locally through indoor farming cuts down transportation emissions and ensures a fresher product. Indoor farms also use about half the amount of fertilizer and don’t need to use pesticides.

Surprisingly enough, however, pests can infiltrate even this kind of highly controlled environment, which would, of course, compromise the kosher status of the product.

How do bugs enter?

“There are three major ways,” Rabbi Sharratt explaines. “People themselves can unwittingly bring in bugs, pathogens or diseases, which is why most indoor farms have gowning procedures for employees (putting on lab coats, et cetera) before entering the grow room. Additionally, pests can be dormant, hiding in the grow media (the mixtures of components, such as peat moss or sand, that provide water, air, nutrients and support to plants).”

Dormant pests can even be found in the seeds. “This is why most vertical farm companies are very particular about their seeds,” he says. “They don’t want to bring in pathogens. Many vertical farming companies will only purchase seeds that are tested and certified.”

As part of the process to determine if an indoor farm company can become OU certified, Rabbi Sharratt will look at the company’s standard operating procedures for biosecurity measures. He’ll ask: How robust are the procedures? Is there a gowning procedure before entering the grow room? What sort of filters are they using for the HVAC  system? He also looks to see what kind of pest management program the company has in place, and he evaluates the risk factors of an outbreak. Finally, he will take samples and analyze whether or not the product is clean. “Even after certification, mashgichim need to check systems and controls and take samples in indoor farms,” he says.

What happens if an insect outbreak occurs? Many vertical farming companies will resort to buying “beneficial pests” such as the ladybugs mentioned earlier. “The challenge of getting rid of the beneficial pests depends on the type that was released,” says Rabbi Sharratt. “Some pests are genetically modified to east each other if there’s nothing else left to eat. So, to some extent, they clean themselves up.”

Mishkenot Yaakov (Rabbi Yaakov ben Aaron of Karlin, d. 1844) rules that fruits, vegetables or berries that are on average found to be infested at a rate of 10 percent or more always require checking beforehand. This 10 percent-or-higher probability of an unfavorable outcome is termed miut hamatzui. A less-than-10 percent likelihood of an unfavorable outcome is considered statistically and halachically insignificant in this area. Dr. Bruce Bukiet, professor of mathematical sciences at the New Jersey Institute of Technology, used basic probability methods in order to determine the criterion the OU could use for vegetable checking. He created a progressive statistical model to determine a field’s acceptability with an accuracy level greater than 90 percent. Dr. Bukiet wrote a series of reports and met with Rabbi Yisroel Belsky, zt”l, who approved the statistical sampling methods as OU policy.

—By Rabbi Dovid Bistricer

Plant Intelligence

Even more intriguing are new technologies that pick up on plant communication. “Shlomo Hamelech was said to have understood the language of plants,” Rabbi Sharratt says. “Today we can actually pick up their signals by putting electrodes into them to monitor their electric currents, and we’re learning to decipher their signals.” For example, if a match is lit near a plant, the plant emits higher electrical activity. When menaced by too much heat, cold or predators, plants emit chemical compounds that alert each other, and mount their own collective defense: they produce leaves or fruits that are more bitter, contain insect-repelling compounds, or are more hairy. There’s evidence that the roots of plants also emit chemicals that serve as messages to neighboring plants. Even plants of different species “talk” to each other. 

Artificial intelligence is now being used to figure out how to read these messages and diagnose plant problems. Brown spots on a leaf can signal a variety of things: disease, rot or insects that suck the juices. The faster farmers can determine what the problems are, the better their yields will be.

Artificial intelligence is also being used for predicting climate events that affect crop yields. One company, for example, which grows soy and corn in South America and Africa, uses AI to create robust predictive models for climate. This allows farmers to be proactive when crop-threatening events like floods, droughts and pests are imminent.

Drones are another high-tech means of keeping an eye on the status of fields. Rabbi Sharratt notes, “They can give great input about the condition of acres and acres of fields, with zero human labor involved.”

While the indoor farming industry is still in its infancy, Rabbi Sharratt and others in the world of kosher certification believe it has extraordinary potential for kosher consumers, whose options are limited when it comes to fresh produce because of infestation issues.

“Indoor farming can bring about a revolution for the kosher consumer. If it’s done correctly, the vegetables could be grown bug-free and won’t require washing,” says Rabbi Sharratt. “Today most produce that is ‘pre-checked’ for insects generally goes through an intense washing system, but when produce is washed so intensely, the quality of the product often suffers. Fragile produce like basil, for example, can’t be pre-washed in this manner.

 “In a few years, we are going to finally have fresh raspberries and blackberries that we can eat,” he says. “As the industry grows, this will open up whole new possibilities for kosher consumers.”


Barbara Bensoussan is a frequent contributor to Jewish Action.


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Digitalization and What It Means for Kashrut by JA Staff

Meet the New Meat: Plant- and Cell-Based Alternatives by Merri Ukraincik


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Even the Stones are Treif: The Kashrut Chaos that Spurred the Founding of of the OU by Dr. Rafael Medoff

Keeping Kosher, Becoming American: A Brief History of OU Kosher by Dr. Rafael Medoff

OU Kosher Through the Decades: A Timeline

OU Kosher: The Inside Story

Meet the Mashgichim

Legends in the Kosher World

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The Technology Behind OU Kosher by Rachel Schwartzberg

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This article was featured in the Winter 2022 issue of Jewish Action.
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