The U.S. Department of Agriculture issued a public health alert Thursday for ground beef sold by supermarket operator Safeway Inc.

The USDA said the meat could have been contaminated with Salmonella Newport, a bacterium that can cause severe gastrointestinal illness. The health agency is advising people to check their freezers and to discard any ground beef products that were purchased between September 19 and November 5 from any Safeway supermarket.

The Pleasanton, California, food and drug retail said ground beef in its stores today is not the subject of the alert and that no Safeway product has tested positive for Salmonella Newport to date. No illnesses have been reported in Hawaii or New Mexico. A single case was reported in Idaho, but it seems to have no connection with Safeway, the company said, according to Forbes.

Food contaminated with Salmonella can cause salmonellosis, one of the most common bacterial foodborne illnesses, which can be life threatening, especially for those with weak immune systems, such as infants and the elderly. The most common symptoms of salmonellosis are diarrhea, abdominal cramps and fever within eight to 72 hours. People may experience additional symptoms like chills, headache, nausea and vomiting that can last up to seven days.