How often does pet food make a cat or dog sick? Does your pet carry the harmful bacteria without showing any symptoms and, if so, for how long? And what precautions can you take to keep you and your family safe?

These are some of the questions now under study by the Veterinary Laboratory Investigation and Response Network (Vet-LIRN) at the Food and Drug Administration (FDA). “Ultimately, we’re hoping to learn ways FDA can help minimize the incidence of foodborne illness associated with pet foods and treats,” says Renate Reimschuessel, V.M.D. (Doctor of Veterinary Medicine), Ph.D., research biologist and head of Vet-LIRN.

Under Vet-LIRN, FDA partners with 34 state and university veterinary laboratories across the country to investigate concerns reported by pet owners. Over the past two years, 11 of the Vet-LIRN labs have focused specifically on Salmonella infections in dogs and cats.

Researchers are currently analyzing the data, and hope to publish study results no later than 2016. Careful attention is given to quality control. While final results aren’t available at this time, Reimschuessel says that the news for pet owners appears to be pretty good. Out of 2,965 animals tested, researchers have found fewer than 100 actually testing positive for the bacteria.

“Pet owners should know, though, that almost half of the dogs that tested positive for Salmonella showed no symptoms,” Reimschuessel says. A dog may show no signs of illness yet still carry the bacteria, which can potentially spread to other members of the household. Moreover, for young children, older adults, or individuals with compromised immune systems, bacterial illnesses can be especially serious.

Additionally, the dogs that tested positive for Salmonella were more likely to have eaten raw pet food, study results show. Scientific literature indicates that raw foods are more likely than processed foods to test positive for Salmonella and Listeria monocytogenes, another common cause of disease, in part because they have not gone through a “kill step,” such as heat processing.

The FDA routinely conducts sampling assignments to inform its research and surveillance activities, and this year will sample raw pet food products. The results from sampling assignments help the agency target its resources to areas that have the greatest impact on public health.