Yum! Brands removed fresh onions from some of its Taco Bell, Pizza Hut and KFC locations as the restaurant industry contends with an E. coli outbreak. 

The company is pulling the ingredient “out of an abundance of caution,” it said in a statement Thursday to Bloomberg News, without disclosing which stores and regions were affected or naming suppliers.

“We will continue following supplier and regulatory guidance to ensure the ongoing safety and quality of our food,” the company said.

Also read: Marketing experts react to McDonald’s E. coli response 

Yum shares fell 0.5% at 1:48 p.m. ET, paring an earlier steeper decline. The stock has advanced about 2% so far this year, well below the 22% gain for the S&P 500 Index over the same period. 

The restaurant industry is on alert after the U.S. Centers for Disease Control and Prevention said Tuesday that an E. coli outbreak likely tied to onions served on McDonald’s Quarter Pounders killed one and sickened dozens of people in the U.S. 

McDonald’s pulled the popular product from about 20% of its more than 13,000 US restaurants, and it’s working with health authorities to confirm the source of the contamination.

Taylor Farms, which supplied onions to the impacted McDonald’s restaurants, recalled some batches of its yellow onions out of caution, even though it hadn’t found traces of E. coli as of Wednesday. Restaurant distributors US Foods Holding Corp. and Sysco Corp. notified customers of the recall as well.

—Bloomberg News