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Dan White, cofounder and CEO, Clean Crop Technologies
Dan White, cofounder and CEO, Clean Crop Technologies

Seed treatment, without compromise? Cold plasma is ready for prime time, says Clean Crop Technologies

May 7, 2024

Massachusetts-based Clean Crop Technologies has launched a commercial cold plasma seed treatment facility, signed $3.4 million in purchase orders, and has a sales and pilot pipeline worth $47 million in annual recurring revenue from companies that represent 39% of the global vegetable seed market, claims the startup.

While hot water and chemical seed treatments are effective at tackling pathogens, they can also reduce germination rates, says the firm, which uses ionized gases to disinfect seeds instead.

“You can choose between killing the contaminant, and in so doing harm the germination of the seed, or you can make sure you have vigorous seeds, but not be able to kill everything,” claims CEO Dan White, who cofounded Clean Crop Technologies in 2019 with plasma tech expert Dr. Kevin Keener and former Cargill executive Daniel Cavanaugh.

“We started out looking at post-harvest applications and we’ve done a lot of work on mycotoxin mold reduction, but for the next several years, we’ve decided to focus exclusively on seeds,” White told AgFunderNews.

“In 2023, we built out our first commercial system, and now we have a piece of commercial hardware that’s at scale for vegetable seeds. We have a tolling line, which is pretty typical for seed treatments, so customers send us the seed, and we treat [decontaminate] it [with ionized gases] in our class 7 cleanroom for a flat rate per pound. We then package it aseptically and send it back.”

Depending on the seed type and customer requirements, speeds range widely “from a few pounds to over a hundred pounds per hour per machine,” said White. “But we are building the machines for modularity, allowing us to match line speeds of hundreds of pounds per hour with multiple machines in parallel.”

Longer term, he anticipates Clean Crop Technologies’ machines will be operating at the seed companies themselves, added White, who is also working with growers in the greenhouse, micro-greens, and sprouts markets.

‘We’re seeing significant demand in high value vegetable seeds’

According to White: “We’re seeing significant demand in high value vegetable seeds such as broccoli, carrots, cauliflower, tomatoes, peppers, and this year is all about scaling capacity to meet that demand. But we also have a long pipeline of other applications in row crops and lower value vegetables such as spinach.”

He added: “Last year, we got our first machine up and running, figured out all the business operations to be able to run a tolling line, which is not trivial. We also secured clearance from the EPA to be able to make pesticidal claims, which was a really big win for us to be able to treat seeds. And then early this year, we got certified as an organic seed handler, which opens up that market for us also.”

What is high voltage atmospheric cold plasma technology (HVACP)?

Clean Crop Technologies deploys high voltage atmospheric cold plasma technology (HVACP) to inactivate a broad spectrum of contaminants from seed surfaces in a dry, automated, and residue-free process, says CEO Dan White.

“We’re using electricity to generate ionized or highly energetic gases to preferentially break down certain microbes, without harming the quality [of the food] in the process. We have the ability to tune those gases so we’re preferentially breaking down stuff that is traditionally very hard to do, so things like Salmonella, Listeria, E. coli, and a wide range of mycotoxins.”

Clean Crop Technologies team
Quality assurance officer Michaela Elliott and senior R&D process engineer Sandon Hess. Image credit: Clean Crop Technologies

The regulatory pathway

Under the US Environmental Protection Agency (EPA), Clean Crop Technologies’ cold plasma tech is considered a pesticidal device, White explained.

“There’s a decision tree they go through where they say, are you making pesticidal claims? If so, do you leave residues on the product that you’ve treated? If the answer is yes, which is the case with 98% of pesticide products, you have to go through the pathway that most people think of, which can involve years of validation and environmental studies.

“If you don’t leave residues in the seed, and we don’t, so there’s no difference being treated and untreated seed, you can be fast tracked as a pesticidal device. But for every claim we make, we have to have scientific evidence to back it up, we have to be a registered manufacturer and keep the EPA apprised of all of our activities and claims. So it has required a fair amount of due diligence and data collection.”

The business case for HVACP

A sizable percentage of food crops never leaves the farm, in part because market prices may be too low to justify the cost of making additional passes through fields or orchards to harvest crops, labor is scarce, or produce is too ripe or ugly for its target market, according to USDA.

But molds, pests and other pathogens also play their part, said White. “The vector for those contaminants is either the soil or it comes in from the seed itself. Today the tools that are mostly used to address those are fairly limited, such as hot water, chemical washes, and fungicidal coatings, which tend to force seed companies and growers to choose between seed that is clean or seed that has good vigor, germination, and viability.”

Every crop is different, he stressed, “but we found that for seed companies that use our treatment, they can sell safely to growers a higher percentage of their crop. Then at the grower level with some of our customers, they’ve been able to see an increase in yields either from reducing that pathogen pressure, or because they can stop using existing controls such as wet chemical treatments that can harm germination.”

On cost, Clean Crop’s tech tends to be “benchmarked against the cost of hardware and labor for wet treatments, which are very labor intensive,” he said.

“It can take multiple days to wet and dry seeds and if you dry them too fast seeds can die and if you dry them too slowly, they can start germinating. We’ve only gotten into applications where we’ve been able to show out of the gate that we are at cost parity or below the existing technology.”

Cold plasma for seed treatment: We’re finally at the point where it’s starting to get taken seriously’

While cold plasma is not a new concept, it is only now beginning to pick up traction in the seed treatment arena, said White, who said Clean Crop has “a robust IP portfolio protecting both our process and hardware… It’s something that’s been around for decades within academia, but we’re finally at the point where it’s starting to get taken seriously [in crop protection].

“So in this space now there is us and [UK-based startup] Zayndu, and a few university labs that may spin out companies in the next few years. It’s still early days, but we’re finding that this treatment is a lot more robust, a lot more dynamic, than we thought a few years ago. Now we have a strong handle on what are the key questions to ask, what are the key tests to run, and we’ve collapsed that adaptation process from months to weeks [for a new crop].”

He added:Our key differentiators are a cluster of process innovations that enable a fully automated and scalable treatment system, achieving customer requirements in minutes, where most batch processes we are aware of require hours. 
“We are using atmospheric plasma today, but have built our company to leverage the state of the art in plasma to enhance seed cleanliness and performance. We are constantly iterating across a wide range of process conditions to achieve this, including pressure.”

Given that soil, as well as seeds, can be a vector for pathogens, how much difference will cold plasma seed treatments make? According to White: “Season over season, there’s no persistent effect [of our seed treatment] on soil, but what’s really interesting is that as seeds travel the world, they’re spreading diseases that then become endemic in the soil.

“So over time, if you’re able to reduce that pathogen load on the seeds before they go into the field, over 10 or 20 seasons, you may be able to reduce that overall pressure as long as growers are rotating crops effectively.”

Unit economics and funding

Asked about funding, he said, “We’ve now raised $13 million and we’ll be going back to market later this year, early next year [to raise more]. I think the one thing that has definitely shifted compared to say two years ago, is that there is now much less of a focus on growth at all costs and much more interest in unit economics.

“So that’s really where we are focused and we have very good unit economics today. We have the fundamentals of a really scalable, profitable business. There are obviously hardware costs upfront, but we’ve developed a pretty a pretty solid financing strategy that’s enabled us to onboard machines without putting them on our balance sheet and pay them off as a function of recurring revenue in a really competitive way.

“We’ve built a flywheel that is going to enable us to build and deploy these machines without having to finance them with equity financing.”

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