Yum Brands is pulling onions from select locations following the E. coli outbreak at McDonald's

Delicious brands has removed onions from some Taco Bell, KFC and Pizza Hut locations following an E. coli outbreak linked to McDonald's.

“As we continue to monitor the recently reported E. coli outbreak and out of an abundance of caution, we have proactively removed fresh onions from select Taco Bell, Pizza Hut and KFC restaurants,” a Yum Brands spokesperson said in a statement to CNBC. “We will continue to follow supplier guidelines and regulations to ensure the ongoing safety and quality of our food.”

Restaurant supplier US Food issued a recall notice Wednesday for four onion products manufactured by Taylor Farms. It is unclear whether Yum has removed the bulbs from select locations in response to the recall.

US Foods does not distribute onions to McDonald's restaurants and the burger chain has not publicly named Taylor Farms as a supplier. Taylor Farms did not respond to CNBC's request for comment.

Health authorities are investigating the source of the E. coli outbreak, which has resulted in one death and 49 confirmed cases in 10 states, including Colorado, Nebraska and Wyoming. The Centers for Disease Control and Prevention surveyed 18 people as of Tuesday, 14 of whom recalled eating a Quarter Pounder burger from McDonald's.

In response to the outbreak, McDonald's has pulled Quarter Pounders from about a fifth of its U.S. restaurants. The investigation focused on two ingredients in the burgers: the fresh beef patties and the chopped onions.

McDonald's said the affected restaurants source all onions from a single facility that washes and cuts the onions. The beef meatballs, on the other hand, come from several suppliers in the region. If cooked to internal standards, the temperature would kill any E. coli in the patty.

– CNBC’s Kate Rogers contributed to reporting on this story.