A 14-year-old’s award-winning invention uses AI to detect pesticides on fruit and vegetables

Subash’s device can detect pesticides on produce with 93% accuracy.

When 14-year-old Sirish Subash was told to wash his produce before eating it, he did what any inquiring young mind might do: he asked himself “Why?” Then, he got to work.

Subash wasn’t satisfied with the explanation that washing removes potentially harmful pesticides from produce. He wanted to know how effective washing actually was, so for this year’s 3M Young Scientist Challenge, he set out to invent a device to answer that question.

He spent about 11 months researching and developing what ultimately became a handheld device, called Pestiscand. It attaches to a smartphone and uses AI to detect the presence of certain pesticides on common produce.

Pestiscand attaches to a smartphone to detect the presence of pesticides on produce.

To use it, you download a phone app, point Pestiscand at the fruit or vegetable, and tap the scan button, Subash told B-17. If the scanner detects the presence of pesticides, you should give the fruit or vegetable another rinse.

“It can often take multiple rounds of washing to significantly reduce the quantity of pesticide residues from produce,” he said.

The device won him the $25,000 grand prize at this year’s 3M Young Scientist Challenge, beating out nine other competitors. Gilles Benoit, a judge for the challenge, told B-17 over email that part of what set his project apart was its potential to help improve everyday health and safety.

“Diet is really one of the main roots of exposures to pesticides,” Alexis Temkin, a senior toxicologist with the Environmental Working Group who wasn’t involved with the competition, told B-17. “And there’s some evidence that shows dietary exposure can be linked with really serious health effects.”

Certain pesticides have been linked to a greater risk of type II diabetes, postmenopausal breast cancer, birth defects, and some cancers.

An AI-based handheld device that detects pesticides

Subash won $25,000 for his handheld invention.

Pesticscand relies on a noninvasive technique called spectrophotometry, which shines a light on a piece of produce and then uses AI to analyze the light that’s reflected back to identify what pesticide, if any, is present.

“His project exemplifies how AI is becoming more accessible, even to the youngest scientists,” Benoit said.

For the challenge, Subash tested four common fruits and vegetables: apples, spinach, strawberries, and tomatoes. He then divided the fruits into four batches.

The first three batches he sprayed with one of three common pesticides — azoxystrobin, imidacloprid, or cypermethrin — and the fourth batch he washed thoroughly for his pesticide-free control.

While testing the device, he scanned each piece of produce multiple times in different locations, taking over 800 samples. Pestiscand can accurately identify both the presence of pesticides and which pesticide is present 93% of the time, he said.

The device is still in its preliminary stages. Eventually, Subash hopes to develop a product that can identify the many hundreds of potential pesticides and estimate how much pesticide is left after an initial wash to determine if another rinse is necessary.

For example, strawberries have grooves and crevices that make it “easier for biological and chemical contaminants to kind of stay on those for longer and it’s harder to wash them off,” said Danya de Montagnac, a pesticide research fellow at EWG.

How to reduce your exposure to pesticides

Washing your produce is one of the best ways to remove pesticides from produce.

Even though washing produce may not remove all pesticides, it’s one of the best ways to reduce your exposure, de Montagnac said. She recommends washing for 15 to 60 seconds depending on the produce — for produce that typically contains a lot of pesticides, wash longer.

Another option is to buy organic, particularly for items that contain high pesticide levels like grapes, kale, peaches, pears, and nectarines, according to the EWG.

Organic produce still contains pesticides, but they’re natural. It’s the synthetic pesticides on conventional produce associated with adverse health effects, Temkin said.

Just because produce contains pesticides doesn’t mean you should avoid it altogether.

“The majority of the population already is not eating enough fruits and vegetables. So by no means should concerns about pesticides sort of get you to avoid fruits and vegetables,” Temkin said.