If you give your dog pig ear treats, you could be at risk of contracting salmonella.

Public health and regulatory officials are investigating a multi-state outbreak of human salmonella infections and a suspected link to contact with the popular dog treat, which are made of smoked pig.

According to the Centers for Disease Control and Prevention and the Food and Drug Administration, the salmonella outbreak has sickened 45 people from 13 states. Twelve people have been hospitalized.

Pet Supplies Plus is voluntarily recalling bulk pig ear products sold in all of its locations in 33 states "due to the potential of Salmonella contamination," according to the recall notice posted on the FDA website. Prepackaged pig ears are not included in the voluntary recall.

However, the pet supplies store said in a company statement that "none of these cases are confirmed to be a result of purchasing pig ears from Pet Supplies Plus."

The CDC also said "a common supplier of pig ear dog treats has not been identified."

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Testing by the Michigan Department of Agriculture and Rural Development found that an "aging bulk pig ear product in one of our stores tested positive for Salmonella," Pet Supplies Plus said in a statement.

"We have pulled bulk pig ear product from the shelves at all of our stores and have stopped shipping bulk pig ears from our Distribution Center," the pet store chain said. "We are working with the FDA as they continue their investigation as to what caused the reported Salmonella related illnesses."

The recall affects bulk pig ears that were sold in bins at Pet Supplies Plus stores in Alabama, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Massachusetts, Maryland, Michigan, Minnesota, Missouri, North Carolina, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia, West Virginia and Wisconsin.

Salmonella symptoms

Out of the 45 total cases, the most were reported in Iowa with 12, followed by Michigan with seven and then New York with six.

Illinois, Indiana, Kansas and Missouri each had three; Massachusetts and Pennsylvania had two a piece; and California, North Dakota, South Carolina and Wisconsin each had a single case.

Salmonella can affect animals eating the products and humans are at risk from handling contaminated pet products, especially if hands have not been thoroughly washed after contact has been made with the pig ear products.

The symptoms of salmonella in humans include diarrhea, fever and abdominal cramps, and they usually develop 12 to 72 hours after eating a contaminated product, according to the CDC.

Some dogs may have a salmonella infection but may not look sick, the CDC said, noting dogs with an infection usually have diarrhea that may contain blood or mucus. Affected animals may seem more tired than usual, and may have a fever or vomit.

According to the CDC, 34 of 38 ill people interviewed by health officials reported contact with a dog before getting sick and of 24 people with available information 17 or 71% “reported contact with pig ear dog treats or with dogs who were fed pig ear dog treats.”

What should pet owners do?

The CDC recommends pet owners wash their hands thoroughly with soap and water after handling pet food and treats, including pig ears.

Store pet food and treats securely away from human food and young children.

Don't let your pet lick your face, mouth or open wounds after it eats pet food or treats.

Don't allow children younger than 5 years old to touch pet food or treats.

Contributing: Monroe Trombly, Mansfield News Journal; Kellie Hwang, Indianapolis Star

Follow USA TODAY reporter Kelly Tyko on Twitter: @KellyTyko