New Hampshire health officials are investigating an outbreak of E. coli associated with ground beef. 

Since June, 12 people in the state have been infected with the same strain of E. coli after eating ground beef, according to the state Department of Health and Human Services’ Division of Public Health Services. The safety of ground beef is regulated by the U.S. Department of Agriculture, which is assisting the state investigation.

“Ground beef is a known source of E. coli and it is important for people to avoid eating under-cooked ground beef whether at home or at a restaurant,” said Marcella Bobinsky, acting director of the state DPHS. “Young children and the elderly are especially vulnerable to severe illness with this infection.”

The people who became ill ate ground beef at a number of different locations. State health officials and the USDA are working to identify the specific source.

Ground beef should be cooked at a temperature of at least 160 degrees Fahrenheit.