The majority of Wellness natural products for pets are produced in WellPets facility in Mishawaka, Indiana. WellPet said it no longer purchases any products from Diamond Pet Foods.

Solid Gold Health Products for Pets, Inc. also announced a voluntary recall of two batches of their products distributed in the United States and Canada. The company is recalling one batch of WolfCub Large Breed Puppy Food and one batch of Solid Gold WolfKing Large Breed Adult Dog, both with a Best Before date of December 30, 2012, and an "X" in the 11th digit of the date code.

Solid Gold said the recall was precautionary, as the products were manufactured at the South Carolina facility that has been linked to recent recalls of Diamond brand pet foods.

Natural Balance Pet Foods had also issued a voluntary recall of certain dry pet food formulas manufactured by Diamond at the same facility. Visit the Food and Drug Administration (FDA) website for a list of the recalled Natural Balance formulas.

According to the American Veterinary Medical Association (AVMA), contaminated additives that are added to pet foods after cooking can cause contamination of the food.

"Because pet foods and treats contain animal-origin products, they are at risk of contamination with Salmonella, E. coli, and other organisms," the AVMA wrote in a FAQ. "In general, these products are cooked to temperatures that will kill these organisms – however, if a contaminated additive (a flavoring, for example) is added to the food after cooking or if the food comes in contact with contaminated materials, the food will be contaminated. There are many safeguards in place to minimize the risk of contamination during the manufacturing process, but using caution when handling these foods is always recommended."

Individuals handling dry pet food can become infected with Salmonella, especially if they have not thoroughly washed their hands after having contact with surfaces exposed to this product. People who believe they may have been exposed to Salmonella should monitor themselves for some or all of the following symptoms: nausea, vomiting, diarrhea or bloody diarrhea, abdominal cramping and fever.

According to the Centers for Disease Control, people who are more likely to be affected by Salmonella include infants, children younger than 5 years old, organ transplant patients, people with HIV/AIDS and people receiving treatment for cancer.

Pets with Salmonella infections may have decreased appetite, fever and abdominal pain. If left untreated, pets may be lethargic and have diarrhea or bloody diarrhea, fever and vomiting. Infected but otherwise healthy pets can be carriers and infect other animals or humans.