These High-Tech Sensors Track Exactly How Fresh Our Produce Is So We Stop Wasting Food

How often have you gone to a grocery store, picked out what seems to be a fresh pint of blueberries, and opened the refrigerator door the next day to find half of them covered in mold? If your answer is “all the time,” you’re not alone: Those best-by dates that give us such blind confidence in the shelf life of our produce are nothing more than “a soft assurance,” says Peter Mehring, CEO of Zest Labs, a Silicon Valley-based tech company dedicated to preserving produce and grocery product quality along the supply chain. And in addition to frustrating customers, inaccurate sell-by dates result $30 billion of wasted food in the U.S. each year.

Through its new Zest Fresh tool, which was rolled out last fall and is now delivering measurable results, Zest Labs is helping food retailers better identify best-by dates to reduce the food wasted in transit or tossed after rotting unsuspected in fridges. Zest Fresh, Mehring tells Fast Company, uses real-time, sensor-based tracking to consistently monitor the freshness of a product, from time of harvest to when it hits retail shelves. Given that in the U.S. around $165 billion worth of food, or 40% of the total produced, is thrown out into landfills each year–with losses related to inconsistent freshness and sell-by dates accounting for 33% of that–Mehring and the team at Zest Labs saw an opportunity to use tech to cut back on some of that waste.

For retailers and farmers, implementing Zest Fresh technology is simple: All that’s required is installing sensors, which detect temperature, moisture, and location, on the produce pallets assembled in the fields before distribution, and connecting the sensors to the Zest Fresh cloud, which disseminates data to the various players along the supply chain. Most retailers, when they source produce from growers, expect it to arrive from the distribution center with 10 days of freshness remaining. In a series of baseline studies conducted at retailers throughout the country, Mehring found that only 30% of products actually arrived with that target freshness. After installing Zest Fresh technology in the pallets of farmers they source from, the number of products that arrived with 10 days of freshness to spare jumped to over 90%.

The way Zest Fresh is able to deliver on this improvement, Mehring says, is because it’s the first technology to actually develop a reliable freshness metric. Previously, “best-by” dates were determined by a general assumption of freshness, based on product type, distance traveled, and eyeballing. The ZIPR code–which stands for Zest Intelligent Pallet Routing and was developed by Zest Labs to facilitate the Zest Fresh tool–delivers a freshness metric based on the specific conditions of each item, which allows workers along the supply chain to adjust their decisions so the produce at the store is the most fresh. The ZIPR codes are tailored specifically to each product based on their rate of respiration–the process by which produce runs through the supply of sugar keeping them edible once they’re harvested. Cooling slows the respiration rate, which varies widely by type of produce; the ZIPR code accounts for those variations and issues cooling instructions accordingly.

Say you’re a lettuce farmer, and you’re working on getting a harvest to the distribution center. “The problem is, there’s an assumption that all produce harvested on the same day will have the same shelf life,” Mehring says. “That’s historically how sell-by dates are determined.” But in reality, a pallet of lettuce assembled in the early morning and sent immediately to the cooling center will already have a longer shelf life than a round from the same crop that was cut and assembled later in the day and left out in the hot sun for a while before making it into a refrigerator.

For each product, Zest Fresh provides a target ZIPR code that a pallet must hit in order to proceed along the supply chain (the ZIPR code is derived from the data sets tracked through the Zest Fresh cloud, and reflects both the product type and its temperature and exposure to humidity over time). Based on where a pallet’s ZIPR code falls in relation to the target code, Zest Fresh offers an estimate for the days of freshness remaining for each pallet. That estimate is dynamically updated along the supply chain; any time a product is mishandled–say, left out of a cooling facility for too long–the remaining freshness estimate will reflect that. “That allows someone in the distribution center to make an intelligent decision and say, ‘Okay, I expected 10 days of freshness, but this product only has 8 days left–I better send it to the store this afternoon instead of tomorrow,’” Mehring says. “We’re giving people actionable data to take corrective steps.”

A recent study from Chainlink Research on the need for achieving consistent quality along the produce supply chain highlighted the ZIPR code and Zest Fresh as the first innovators in the space, and while the technology is still new, Mehring believes there’s room to scale. Zest Fresh uses a flexible payment model–while the retailers and farmers Zest Fresh works with won’t release financials, Mehring says they pay Zest Labs 10% of the value of the waste they avoid by using the platform. Zest Fresh, Mehring says, aims to reduce a retailer’s waste by at least 50%, so the tech company will earn 10% of that, and the retailer will still see a boost to their bottom line and efficiency. Right now, Zest Fresh is mainly working with produce, but the technology can and will scale up to beef, poultry, and seafood distribution chains this year; the technology will track the same temperature and humidity conditions, and adjust the ZIPR scores based on the specific needs of the product.

When it comes to reducing supply-chain and retail food waste in the industry, this data-driven approach, Mehring hopes, will be a game changer. Clarifying and backing up best-by dates could be a significant factor in reducing unnecessary food waste: A report from the nonprofit ReFED found that standardizing food freshness labels could divert as 400,000 tons of food waste annually, and save $4,547 per ton. Doing so, the report added, would also curb emissions by cutting back on unnecessary transit of products that end up in landfill, and save as much as 192 billion gallons of water.