Clif Bar issued a voluntary recall for three flavors of the company's energy bars. 

CLIF BAR Nuts & Seeds energy bars, CLIF BAR Sierra Trail Mix energy bars and CLIF Mojo Mountain Mix trail mix bars were recalled after the company found ingredient supplier SunOpta distributed sunflower kernels that might be contaminated, according to the U.S. Food and Drug Administration. 

Clif Bar said the company has not received any reports of illness. 

The kernels might be contaminated with Listeria monocytogenes, according to the FDA. The organism can sometimes cause fatal infections for pregnant women, young children, frail or elderly people and others with weakened immune systems. Other symptoms include high fever, severe headache, stiffness, nausea, abdominal pain and diarrhea, 

Retailers have been contacted. Those with questions can call 1-888-851-8456.