SmartPak Canine has voluntarily recalled all lots of LiveSmart Adult Lamb and Brown Rice dog food after samples tested positive for the presence of melamine, the chemical blamed for sickening and killing cats and dogs.

The company, as well as veterinary experts, are especially concerned because the recalled pet foods were not made with contaminated wheat gluten or rice protein concentrate, but they apparently were produced in plants where melamine-tainted wheat or rice products were used to produce other formulas.

"It appears that the products may have been cross-contaminated" at the plant of SmartPak's contract manufacturer, Chenango Valley Pet Food, according to a press release from SmartPak.

The U.S. Food and Drug Administration and a variety of other testing laboratories have determined that wheat gluten and rice protein concentrate are the pet food ingredients that have been contaminated with melamine.

The latest pet food company recall came one day after Menu Foods added more than 220 pet food products to an ever-growing recall list because of fears of cross-contamination.

The pet food recall, which began on March 16, is a "crisis" that "is far from over," according to the veterinary toxicologists and internists at the American Society for the Prevention of Cruelty to Animals. The agency operates a national poison control center and a veterinary hospital in New York City.

"Given the fact that there is new evidence of cross-contamination in ingredients that may have been considered safe prior to this news, we need to be much more aware of where the ingredients in our pets' food are coming from," said Dr. Steven Hansen, a board-certified toxicologist who manages the ASPCA Animal Poison Control Center.

Vegetable proteins contaminated with melamine have been traced back to two plants in China.

The ASPCA (www.aspca.org/recall), FDA (www.fda.gov) and the American Veterinary Medical Association (www.avma.org) are cautioning pet owners to make daily checks on the growing list of recalled products. Their Web sites are providing running updates.

Staff at ASPCA "are strongly recommending" that pet owners investigate where the ingredients in their own pet food come from. They suggest consumers call their pet food manufacturer or check company Web sites.

ASPCA veterinarians are also urging pet owners to consult their own vets at the first sign of possible kidney damage: lethargy, loss of appetite, vomiting, diarrhea or excessive thirst. Now that veterinarians know what they are dealing with, cats and dogs have been recovering if they receive prompt treatment after eating tainted food, officials said.

The release from SmartPak said the company has telephoned or e-mailed 99 percent of the pet owners who feed LiveSmart Adult Lamb. The product is shipped directly to the homes of consumers and only about 220 pet owners had received it.

"There are no bags of potentially affected product on store shelves anywhere in the country," the company said.