Is it rat poison that has sickened and killed an unknown number of pets across the country or is it melamine, a fertilizer and plastics ingredient? Should consumers be wary only of wet pet food sold in packets and cans, or has dry food been contaminated as well?

Media reports Friday about tainted pet food left Mainers wondering whether any of it is safe. Some are taking action. Attorneys for a woman in Portland whose cats are ill have filed a class-action lawsuit against a major pet food manufacturer. Many Mainers are seeking alternative pet foods, according to retailers.

Meanwhile, veterinarian Michael A. Wing of Meadow Wood Animal Clinic in Cornville said Friday he was just as confused as other pet owners.

“They change the information every day,” he said. “You’ve got me. I don’t know what to feed my own dog.”

An official with the U.S. Food and Drug Administration said the organization has received more than 8,000 food-connected complaints from pet owners in recent weeks. PetConnection.com, a Web site that is tracking the issue, said it received reports of 2,400 pet deaths as of Friday morning, although that number has not been confirmed through testing.

Until Friday, many believed that if they fed their pets only dry food, all would be well. New information now has raised questions about any pet product containing wheat gluten, said Wing.

“I would just avoid anything with wheat gluten,” Wing said.

The FDA confirmed that melamine-contaminated wheat gluten from China was shipped to a U.S. dry pet food company but would not name that company until it determined whether any of the wheat gluten was used in making the dry food.

Hill’s Pet Nutrition recalled its Prescription Diet m/d Feline dry cat food late Friday. The food included wheat gluten from the same supplier used by Menu Foods, a company found to have tainted food. The recall didn’t involve any other Prescription Diet or Science Diet products, said the company, a division of Colgate-Palmolive Co.

People for the Ethical Treatment of Animals has asked for a total recall of all pet food, both wet and dry, after a Pennsylvania woman said her cat died of kidney disease after consuming nothing but dry food.

In Maine, sales of natural and organic pet food are soaring and some pet owners have resorted to making their own food.

“That would be great,” said Wing, “but I would be concerned about balancing the animal’s diet.”

Pet Quarters on Stillwater Avenue in Bangor has seen a large increase in sales of canned organic food. “We carry a brand called Wellness that has no wheat gluten,” said manager Laurie Curtis.

“A lot of the owners that come in here are frightened and afraid,” she said. “We just put their mind at ease and show them the options.”

In the wake of a massive recall of wet dog and cat food sold by Toronto-based Menu Foods based on fears they were tainted with rat poison, the FDA revealed Friday that the deadly culprit may be melamine.

Government officials say no trace of rat poison was found during tests of the food at Cornell University and they said it is unclear whether the melamine found in the samples of Menu Foods pet food was responsible for the deaths of more than 18 cats and dogs.

Melamine was found in the urine of cats that died of kidney failure and in the kidney of another dead cat.

Stephen Sundlof, director of the Center for Veterinary Medicine at the FDA, said that melamine could not be conclusively said to be the cause of the pets’ deaths.

“At this point, we do not know how melamine got into the wheat gluten,” Sundlof said at a news conference in Rockville, Md., Friday. Normal inspections of pet food wouldn’t have detected melamine, Sundlof said.

The unexplained deaths prompted Menu Foods to recall 60 million cans and pouches of pet food March 16. The company uses imported wheat gluten to thicken the gravy in pet foods.

Menu Foods recalled wet food sold under brands such as Procter & Gamble Co.’s Iams, Nestle SA’s Mighty Dog and retailers’ own labels, including Hannaford.

Iams dry food isn’t made by Menu Foods and doesn’t contain wheat gluten, Cincinnati-based Procter & Gamble said Friday in a statement.

Sundlof said that FDA investigators found no trace of the rat poison aminopterin in tests of Menu Foods pet food, a chemical that New York state officials said last week was the likely culprit.

The FDA said it had no indication that melamine had been found in any food used for human consumption.

Attorneys for a Maine cat owner Friday filed a federal class-action lawsuit in U.S. District Court in Portland against Menu Foods.

Plaintiff Mara Brazilian of Portland said her two Persian hybrid cats, Fred and Barney, were healthy and active before consuming pouch food made by Menu Foods in January. Within days, both cats became ill and later were diagnosed with severe kidney failure.

The suit seeks damages for medical costs and emotional pain and suffering associated with the loss.

Brazilian said she spent more than $1,200 on initial veterinary care, and spends $200 to $300 a month on medication to keep her cats alive.

The class-action lawsuit is the first in Maine against Menu Foods. At least three other federal class-action lawsuits have been filed in other parts of the country over dog and cat deaths and illnesses caused by the tainted food. Brazilian purchased pet food marketed under the Iams brand, which also has been named in the suit.

For recall information go to petconnection.com. The Associated Press contributed to this story.