Davis, California, USA
December 2, 2025
Tomatoes leaving a field in Firebaugh, California, after harvest. (Hector Amezcua/UC Davis)
Researchers Analyzed Traffic, Temperatures and 1.4 Million Tomato Truckloads
California’s $1 billion processing tomato industry is highly efficient and likely will be able to withstand higher temperatures and traffic congestion with minimal postharvest losses, according to research conducted at the University of California, Davis.
The research, published in the American Journal of Agricultural Economics, analyzed 1.4 million truckloads of tomatoes transported from thousands of farm fields to processing facilities between 2011 and 2020.
“It’s rare that we find an example where climate change is expected to have a negligible effect,” said Sarah Whitnell, who led the research as a postdoctoral scholar at UC Davis and is now at University of Western Australia, Perth. “Ultimately, the supply chain is a well-oiled machine. The losses are relatively small, and while temperature does increase them, it’s not by a huge amount.”
Researchers matched each truckload to California state highway traffic data and hourly temperatures, which ranged from 48 degrees to 108 degrees Fahrenheit. They compared truckloads of tomatoes from the same field and same growing season: for example, one travelling at 5 a.m. when temperatures are cooler and traffic is light with one travelling at 5 p.m. when the opposite is true.
Optimal conditions: Cool weather and traffic
The best-case scenario was when cool temperatures coincided with heavy traffic. The worst-case scenario was hot temperatures combined with heavy traffic. When it’s hot, slow traffic speeds cause spend more time in damaging temperatures.
“If you have this magic scenario where temperatures are cool but there is traffic, you actually have the lowest losses,” Whitnall said. “This is because faster speeds cause vibrations that can increase damage in fresh produce.”
Comparing best- and worst-case scenarios, the share of soft, split or squished tomatoes doubles from about 1% to 2%. This equates to modest losses, the researchers also found.
The findings show that California’s processing tomato industry is highly efficient and could be a model for others, said senior author Tim Beatty, who is chair of the Department of Agricultural and Resource Economics at UC Davis.
“Most supply chains aren’t nearly as efficient as the California supply chain, so what this says is if you’re a very efficient supply chain, you can mitigate the losses associated with climate change,” Beatty said. “It says that adaptation is possible to really reduce loss past the farm gate.”
Industry relationships made research possible
Eighty-four cents of every farm dollar is generated after the product leaves a farm, but most climate change research has focused on how growing is affected. This research looks at that second stage and was possible because of comprehensive public data and detailed transport, tonnage and quality data supplied by industry, Beatty said.
“We know very little about the effects of climate change once product leaves the farm gate,” he said. “I think this paper is one of the very first to actually tackle that.”
The U.S. Department of Agriculture’s Agriculture and Food Research Initiative supported this research.
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