(AP) – It’s been a choppy year for restaurants that lean into lettuce.

Lettuce prices rose sharply in the first half of 2026 due to hot weather in Arizona, where about one-third of America’s lettuce is grown. Now, restaurants are dealing with the fallout from a cyclospora outbreak linked to shredded lettuce that has sickened thousands of Americans.

Taco Bell will likely see the biggest sales impact from the outbreak, which began in late June. Federal health officials first tied the outbreak to shredded iceberg lettuce served at Taco Bell restaurants in Indiana, Kentucky, Michigan, Ohio and West Virginia. Later, the U.S. Food and Drug Administration said customers in Illinois, Kansas, Oklahoma and Pennsylvania were also affected.

Taco Bell said on July 17 that it had voluntarily removed shredded iceberg lettuce supplied by Taylor Farms from its U.S. restaurants. But its customer volume has suffered. As of July 23, Taco Bell visits were 21% lower than average across the U.S., according to Placer.ai, a market research company.

Cases have continued to grow, however, and it’s becoming clear that Taco Bell wasn’t the outbreak’s sole source, said Craig Hedberg, a food safety researcher at the University of Minnesota. As the FDA investigation progresses, officials should get a better understanding of which illnesses are connected and “how complex this outbreak actually has become.”

In the meantime, consumers remain cautious. Foot traffic at Chopt, a salad-focused chain with 105 locations, was down 12% as of July 23, according to Placer.ai. M Science, another market research firm, found that weekly spending at the salad chain Sweetgreen dropped 10 percentage points compared to last year during the first half of July.

Chopt didn’t respond to a request for comment from The Associated Press. Sweetgreen, which has 285 U.S. locations, did not confirm a drop in sales and said in a statement that its food hasn’t been connected to the current cyclospora outbreak.

“We follow rigorous food safety standards and can trace our ingredients from restaurant to farm,” the company said.

The outbreak came on top of an already difficult year for the lettuce industry and people who love eating salads. The retail price of a pound of iceberg lettuce jumped nearly 20% between January and June of this year, according to government data. Consumers paid an average of 33% more last month for all fresh lettuce compared to a year earlier, the U.S. Department of Agriculture said.

Lettuce prices advertised by major grocery stores last week averaged $1.86 for a head of iceberg, 25 cents more than the same week a year earlier, according to the USDA. A head of red leaf lettuce cost 52 cents more at $1.66, and a bunch of romaine had an advertised price of $2.49 — $1.55 higher, the department reported.

Shoppers caught a break with some types of salad mixes, though, which stores advertised at prices 7 to 24 cents cheaper than a year prior, the USDA said.

Elizabeth Canales, an associate professor of agricultural economics at Mississippi State University, said unusually hot weather in Arizona early in the year caused crops to mature too early. That caused big supply gaps until California production began in late April.

Fuel costs, which increased after the U.S. and Israel launched strikes on Iran and Iran blocked most oil tankers from leaving the Persian Gulf, have also been an issue, according to Canales. Lettuce is especially perishable and requires energy for cooling from the time it’s picked to the time it’s sold, Canales said.

“The cold chain needs to be maintained. Cooling and transporting it is very important,” Canales said.

Lettuce has been linked to multiple food poisoning outbreaks in the past, including two in 2018 involving E. coli linked to romaine lettuce grown in Arizona and California.