Taco Bell and Sweetgreen Face Supply Chain Fallout as Parasitic Outbreak Spreads Across U.S.

A fast-spreading parasitic outbreak that has sickened thousands of people across the United States is sending shockwaves through the restaurant industry, prompting Taco Bell to preemptively pull ingredients from select locations and triggering a sell-off in restaurant stocks.

The outbreak is caused by cyclospora, a microscopic parasite that infects the small intestine and causes severe diarrhea, stomach cramps, and fatigue. While federal investigators have yet to pinpoint the exact source of the contamination, the U.S. Centers for Disease Control and Prevention (CDC) reported that more than 30 states have recorded infections within the last two weeks. Michigan has emerged as the apparent epicenter of the cyclospora outbreak, where local public health officials warn that the illness may be linked to contaminated lettuce or salad greens.

In response, Taco Bell—a subsidiary of Yum! Brands Inc.—announced it has “voluntarily and temporarily” removed certain ingredients from select restaurants as a precautionary measure. The fast-food giant did not specify which ingredients were removed, and emphasized that investigators have not officially linked the chain to the outbreak.

“Public health officials haven’t confirmed a link to Taco Bell, to any specific ingredient or supplier, or to other businesses,” the company said in an official statement. “We will continue to closely monitor the situation and follow the guidance of public health authorities.”

Because Taco Bell operates under a hybrid model—directly running some locations while franchising others to independent operators—the response has varied by region. In Michigan, some franchised locations have already stopped serving lettuce entirely, acting on early warnings from local health departments.

The preemptive measures highlight the high stakes of food safety in the modern restaurant industry. For major brands, even the suspicion of foodborne illness can inflict severe reputational and financial damage. Investors reacted quickly on Tuesday; shares of Yum! Brands Inc. fell 2.7% by 3:40 p.m. in New York trading, though the stock remains up about 4% for the year.

However, the market pain was far more acute for Sweetgreen Inc., a fast-casual chain whose business model relies almost entirely on fresh, raw produce. Sweetgreen shares plummeted by as much as 13% on Tuesday, marking its steepest intraday decline since February. Sweetgreen did not immediately respond to requests for comment regarding its supply chain or safety protocols.

“For Sweetgreen if they can’t get lettuce or if lettuce prices skyrocket, it’s a bigger problem,” said Bloomberg Intelligence analyst Michael Halen. “Salads are a massive percentage of what they sell.”

The vulnerability of companies like Sweetgreen underscores a systemic challenge within the agricultural supply chain. Leafy greens and fresh herbs are notoriously difficult to trace. Unlike beef or poultry, which undergo cooking processes that kill pathogens, salad greens are consumed raw. Compounding the issue, processing facilities often co-mingle crops from multiple farms, making it incredibly difficult for federal regulators to isolate the source of an outbreak quickly.

This lack of clear answers has forced independent restaurant owners to take matters into their own hands. In Monrovia, Maryland, The Buzz cafe announced it is removing some menu items due to the cyclospora outbreak. Similarly, Aberrant Ales in Howell, Michigan, has temporarily taken lettuce off its menu.

In Florida, Niki Becker, the owner of a vegan restaurant chain called The Green Table Restaurant, decided to completely remove lettuce from the menu at all of her locations. She also advised her kitchen staff against using raw scallions and fresh basil until the source of the outbreak is identified.

Becker noted that while she has not received any formal recall notices from her commercial food distributors, she felt compelled to act proactively to protect her customers.

“What has me bothered, is that nobody is really saying where it’s coming from,” Becker said.