The Food and Drug Administration has issued another warning, this time for pet food made at a Menu Foods plant in Canada that used melamine-tainted wheat gluten, as well as a Health Hazard Alert for certain dog chews that may be contaminated with salmonella.

This follows shortly after the recalls of dog and cat food by several companies that produce pet food after melamine was found in wheat gluten imported from China and used in New Jersey and Kansas factories.

As of yet, the two different contaminants do not appear to be connected.”My impression is that they are unrelated, but we need to wait and see,” said Patrick Halbur, professor and chairman of veterinary diagnostic and production animal medicine.

According to a news release by the FDA, samples were collected from three different sizes of packages of dog chews, manufactured by T.W. Enterprises, Ferndale, Wash.

Salmonella was found in one of the samples. T.W. Enterprises has recalled pet chews and treats based on salmonella once before, in June 2005.

Salmonella can manifest in many different ways. It might not even cause illness, and the pet owner often cannot tell the pet is infected. It also ranges to more severe cases, Halbur said.

“There are more variant strains that in different species produce a variety of signs, from diarrhea to what we call systemic illness that goes throughout the body and causes a variety of clinical signs depending on the organ that it affects,” Halbur said.

Salmonella carried by animals and handled in pet chews has the potential to infect humans as well, according to the FDA.

The FDA encourages pet owners with pets that have consumed the recalled chews or have the symptoms of salmonella to contact their veterinarian.

No cases of salmonella have yet been submitted to the Veterinary Diagnostic Lab, said Halbur.

The pet chew warning follows closely on the heels of the recalls of many different brands of pet food.

According to the FDA, some samples of pet food have been found to be contaminated by melamine. Melamine is a substance used as a fertilizer in Asia, but not licensed for use in the United States.

Wheat gluten from China, used to make some kinds of pet food, has been found by the FDA to be contaminated by melamine. Tests are still ongoing to see if this is what is causing kidney failure in pets.

“There are animals that have become ill or animals that have died, and they have a history of having eaten the recalled food. These patients also have kidney failure and that’s the primary thing we know so far to look for,” said Claire Andreasen, professor and chairwoman of veterinary pathology.

“The recommendation now is that if an animal has consumed the food, they should be checked by their veterinarian,” she said.

Andreasen said the College of Veterinary Medicine is involved with all aspects of the issue. These include examining and treating pets and testing blood, urine and tissue samples from pets as well as pet food samples.

She said laboratories around the United States will all be contributing their cases to an online database to share their findings.

“We have had 51 cases submitted to date from vets who are working with pet owners who think illness in their pets may be associated with eating pet food. Of those 51 cases, we have 24 to date that fit the case description provided by the FDA,” Halbur said. “So we are first working to prove that the cause of death is consistent with toxicosis [a disease resulting from poisoning].”

Voluntary recalls on certain products have been issued as a precaution by Del Monte Pet Products, Hill’s Pet Nutrition, Menu Foods, Nestle Purina PetCare Company, P&G Pet Care and Sunshine Mills. Menu Foods was the company that reported animal deaths from kidney failure after the animals consumed their product.

According to the FDA’s Web site, the investigation is ongoing.

People have been returning recalled foods for refunds, said Chris Friesleben, assistant director of communications for Hy-Vee. However, there is pet food considered safe that is sold at Hy-Vee stores.

The manufacturers have been giving notices to the places that sell their product when a product is recalled. These products are identified by Universal Product Codes and easily removed from the shelves on notice of recall.

“We compiled a list of all affected products and we sent it out so our stores have an updated list,” Friesleben said.

“When a manufacturer voluntarily recalls a product they have a variety of options available to them. Some of them will ask that the stores return the product to them, some will ask that it be destroyed.”

For now, Andreasen recommends pet owners to go to Web sites that list recalled food to check what they are feeding their pet. Another resource for pet owners is www.avma.org.