AgroChem 101: What Chemicals Get Into Our Food, and Why?
From soil fumigants to shelf-life wax, here's what really touches your food, and how eating organic and local quietly strips most of it away.
OK class, OK class, settle down please. Today we're going to talk about AgroChem. Here's a question for you… raise your hand if you ever think about chemicals in your food.
Yeah, I assumed you would all think about that from time to time.
Food has its own natural chemistry, of course. But it's the added synthetic chemicals that people usually have in mind — and these are worth understanding.
These chemicals are meant to help grow lots of food and then help it travel far from where it's grown — it's why you can buy a red strawberry from a street vendor in New York City in the middle of winter. But, there are tradeoffs.
Today we'll look at some common chemicals that touch our food, from the soil up — some familiar, others less so. Keep in mind that risk depends on both a chemical's inherent hazard and real-world exposure, including dose, timing, and safeguards.
First, a note about "organic."
Organic certification offers a valuable first layer of peace of mind. USDA rules prohibit many synthetic chemicals and require growers to prioritize healthier soil, crop rotation, and beneficial insects before using approved treatments. Certified farms document their practices and undergo annual inspections, creating meaningful limits, transparency, and accountability.
But organic is a baseline, not a complete picture. It doesn't mean nothing was sprayed, and farms vary widely in how they grow. Some permitted treatments, including copper and sulfur, have environmental tradeoffs of their own. That's why it's worth looking beyond the label to understand the farmer and their practices.
In the Soil
Soil fumigants — chloropicrin & 1,3-dichloropropene (Telone)
What it's used for: Injected into the ground before high-value crops like strawberries are planted, to kill the soil-borne pathogens (Verticillium, Fusarium, charcoal rot), nematodes and weed seeds that otherwise build up and crush yields.
What you need to know: Fumigation is really a fix for monoculture. To grow the same crop on the same soil year after year, growers may fumigate it first — suppressing pathogens, weed seeds, and, increasingly, soil-dwelling nematodes, but also disrupting beneficial soil life. The two workhorses are chloropicrin, a potent respiratory irritant, and 1,3-dichloropropene (Telone), which California has listed as a known carcinogen since 1989 and which the EU banned outright in 2007.¹ Neither stays in the ground — which is why the state regulates them as toxic air contaminants and requires buffer zones around nearby schools and homes.² Doing this over and over again for an extended period can degrade the health of the soil, which means there's less good stuff getting into the food.
Glyphosate (Roundup)
What it's used for: A weed killer. Used mostly on genetically modified corn, soy, and cotton bred to tolerate it, and on the ground beneath orchard trees and vines.
What you need to know: It's the most widely used weed killer on earth, and the WHO's cancer agency classifies it as "probably carcinogenic to humans."³ Regulators disagree on what that means at real-world doses — EPA and the EU still call it safe as used — though in 2022 a federal court threw out EPA's safety conclusion as poorly supported and ordered a fresh review, now due in 2026.⁴ Most glyphosate is applied to herbicide-tolerant corn, soy, and cotton, and decades of blanket spraying have bred resistant "superweeds" across nearly 40 states — which only pushes growers to spray more.⁵ The heaviest exposure falls on the people applying it.
So, class, if repeatedly sterilizing the soil isn't the ideal long-term answer, what might farmers do instead?
Yes, Julia, I had a feeling you might have a thought…
"Well, at the risk of turning this into a Rootstock commercial, our partner farms build healthier soil through practices like crop rotation. Some use anaerobic soil disinfestation, where rice bran, a tarp, and the soil's own microbes help control disease.⁶ And certified organic farms can't use Roundup."
Good answer, Julia!
Before Harvest
Insecticides & miticides — e.g. bifenthrin, abamectin, chlorpyrifos
What it's used for: Sprayed on the growing plant to kill the mites and bugs that attack it. Twospotted spider mites and lygus (tarnished plant bug) are the big strawberry pests.
What you need to know: This is the most crowded stage of all — more chemicals hit the growing plant here than at any other point. Strawberries get pyrethroids like bifenthrin, miticides like abamectin, and neonicotinoids — the insecticide class implicated in the collapse of bee populations.⁷ The starkest case is chlorpyrifos, an organophosphate linked to lower IQ and developmental harm in children: EPA moved to ban it from food in 2021, courts sent the rule back, and as of 2026 it's still allowed on about a dozen crops — peaches among them.⁸
Class, what do you all think of pest treatment on food?
OK, Julia again… my, you are quite eager today, Julia…
"Rootstock's certified organic farms can't use these pesticides. Instead, they rely on prevention — beneficial insects and resistant varieties — and limited approved treatments when needed. Pest control as a food web, not a spray schedule."
Once again, good answer, Julia!
After Harvest
Ethylene
What it's used for: A natural ripening hormone. Because fruit is picked early and firm to survive shipping, growers use ethylene gas — or just warmth to promote natural ethylene production — to finish ripening on the way to the shelf.
What you need to know: Ethylene is the same hormone the fruit makes on its own, so there's nothing directly harmful about it. It explains a lot about flavor, however. Bananas are ripened this way — picked green and gassed with ethylene to ripen just before hitting the shelves. The bananas genuinely sweeten, because they carry a big starch reserve to convert.⁹ Most other fruit doesn't: a peach picked early will soften and color up, but its sugar was set on the tree, and nothing adds more sugar.¹⁰ Softening isn't the same as ripening. Strawberries are the extreme — they don't ripen off the plant at all.¹¹
Post-harvest fungicides — imazalil, thiabendazole, fludioxonil, pyrimethanil
What it's used for: Applied in the packinghouse to hold off mold during weeks of shipping and storage. Citrus gets most of it; apples, pears, and stone fruit are treated too.
What you need to know: This is chemistry a fruit only needs because it has weeks of travel and storage ahead of it. It goes on as a dip, a drench, or a packing-line spray — and sometimes blended into the wax coat.¹² The standout is imazalil, the standard citrus fungicide, which EPA classifies as "likely to be carcinogenic to humans" and which shows up on the majority of conventional citrus.¹³
Fruit coatings / wax — carnauba & shellac
What it's used for: Replaces the natural wax that washing strips off during packing, slowing moisture loss and adding shine. Common on apples, citrus, and cucumbers.
What you need to know: The coating itself is benign — fruit grows its own protective wax, commercial washing strips it off, and carnauba (from a palm) or shellac (from an insect) puts it back. It's allowed in organic, too. As mentioned above, that coat can also carry the fungicides — and it's the added fungicide, not the wax, that organic rules prohibit. The goal of the wax itself is sealing in moisture so fruit still looks fresh after weeks in transit.
Finally, class, what changes when fruit doesn't have to travel thousands of miles before reaching your plate?
Anyone besides Julia? No? Julia, take us home…
"Rootstock's fruit is picked ripe, when its flavor and sweetness have fully developed, and sold fresh within days. With a shorter journey, it doesn't need to be picked early or treated to survive weeks in transit. Here in California, we're lucky to have that choice."
Once again, good answer, Julia – relevant and remarkably on-brand!
A Quick Summary
Look at the whole list together and a pattern shows up: this chemistry is about growing a lot of food cheaply, and moving it a long way. This gets in the way of quality. The first half — the fumigants, the herbicides, the insecticides — is the price of monoculture: the same crop on the same ground at industrial scale, where pests and disease pile up and have to be beaten back with chemistry. The second half — the ripening gas, the fungicides, the wax — is the price of distance: fruit picked early and treated to survive weeks in transit.
Two choices strip most of it away. Organic certification removes the synthetic chemicals outright — no fumigants, no glyphosate, no imazalil; growers hold off the same pests and soil diseases the slower way, with crop rotation, cover crops, solarizing or steaming the soil, and resistant varieties. And buying local removes the reason for the rest — fruit picked ripe and sold within days doesn't need gassing or coating for the road. Rootstock's partners do both: nearby farms, growing in variety, organically, and selling while the fruit is still fresh. It's hard work, but it's important work.
Yes, Julia, you have something to add?
"Shopping with Rootstock is not only good for your health — you're sending an important message to the farmers who go the extra mile and do the right thing for our communities and our planet!"
Well said, Julia. I couldn't have put it better myself!
Sources
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1,3-dichloropropene (Telone): California Proposition 65 carcinogen listing (1989); EU ban (2007). — California OEHHA; European Commission, Implementing Reg. (EU) No 1381/2011
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Chloropicrin and 1,3-D regulated as toxic air contaminants; buffer zones required near schools and homes. — California DPR; Inside Climate News (2024)
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Glyphosate classified "probably carcinogenic to humans" (Group 2A). — IARC Monographs, Vol. 112 (2015)
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2022 federal court vacated EPA's human-health finding; registration review due 2026. — U.S. EPA, Glyphosate
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Most glyphosate applied to herbicide-tolerant corn, soy and cotton; glyphosate-resistant weeds in roughly 38 states. — USDA Economic Research Service; Iowa State University, Integrated Crop Management
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Anaerobic soil disinfestation (rice bran and tarping). — UC IPM, Non-Fumigant Alternatives for Soil Disinfestation
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Neonicotinoids linked to wild-bee population decline. — Woodcock et al., Nature Communications (2016)
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Chlorpyrifos neurodevelopmental harm; 2021 food revocation reversed in court; still permitted on ~11 crops as of 2026. — U.S. EPA, Chlorpyrifos FAQ
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Bananas: starch reserve converts to sugar during ethylene ripening. — UC Davis Postharvest Center, Banana
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Peaches: soluble solids (sugar) largely set at harvest, do not rise after picking. — UC Davis Postharvest Center, Peach & Nectarine
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Strawberries non-climacteric: do not meaningfully ripen off the plant. — Mimura et al., ScienceDirect (2014)
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Post-harvest fungicides applied by dip, drench, packing-line spray, or blended into wax. — Pyrimethanil application study, ScienceDirect (2017)
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Imazalil classified by EPA as "likely to be carcinogenic to humans"; detected on the majority of conventional citrus. — U.S. EPA imazalil documents; Environmental Working Group citrus testing
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