A report in the Centers for Disease Control and Prevention’s publication on Thursday links dry dog food to an outbreak of Salmonella infections affecting people in 19 states.

This is the first investigation to identify dry dog food as the source of human Salmonella infections, Dr. Casey Barton Behravesh, co-author of the report said, according to the Washington Post.

Symptoms of Salmonella infection include nausea, vomiting, fever, diarrhea and abdominal cramps. It is also known to become life-threatening usually for people in bad health or weakened immune systems, such as young children and the elderly.

CDC officials are unsure how the bacteria got into the dog food, as Salmonella usually comes from undercooked meats and eggs.

“They are a number of possible ways that that could happen. That’s something we are still trying to figure out,” Dr. Barton Behravesh said.

According to the report in CDC’s Morbidity and Mortality Weekly Report, at least 70 people in 19 states became infected with Salmonella in 2006 and 2007 from dry dog food produced by Mars Petcare in Pennsylvania. About 40 percent of the cases involved infants. The pet food plant shut down from July to November 2007 for cleaning and disinfection. Also, two brands of the dry dog food were recalled to stop Salmonella infection from spreading.

In response to the findings of the report, Dr. Barton Behravesh urges pet owners to wash their hands immediately after handling pet food. He further recommended parents keep their infants away from pet feeding areas. Also, children younger than 5 should not be allowed to touch or eat pet food, treats or supplements.