In the latest development in the pet food scare, the Federal Drug Administration (FDA) said that it had not found rat poison in the tainted pet food, but melamine, a chemical commonly used to make plastic cutlery, and also used in fertilizer in Asia.

Hours after the announcement, the nationwide pet food recall, which had involved only so-called wet foods — all manufactured by Menu Foods and sold under a variety of brand names — was expanded to include one brand of dry cat food, Prescription Diet m/d Feline, made by Hills Pet Nutrition.  The brand was found to have been made with a batch of wheat gluten shipped to the United States from China that the FDA said was laced with melamine.

Gluten is a glycoprotein that's found in wheat, oat and barley. It's used to thicken, and to make gravy in wet food. It may also be used in dry food as part of a protein supplement or a carbohydrate source.

You want to pick a dog food that conforms to minimal AAFCO (Association of American Feed Control Officials) standards because AAFCO officials strictly regulate pet food.

You want to pick pet foods that have good sources of animal protein. If you look at the ingredient list, it is listed in descending order by amount — just like humans. So the first two or three ingredients should be some type of animal protein — chicken, beef, fish, lamb, beef or turkey. They shouldn't be vegetable, wheat or grain, or animal by-products.

The pet food — can or bag — should have an expiration date. And it should have a phone number and/or website, so you can call the company and ask questions. These are the things that are going to be on high-quality pet foods. You also want to look for natural preservatives, like vitamin C or vitamin E, and stay away from chemical preservatives. Ethoxyquine is one that they used years back that was determined to be a carcinogenic, and are no longer using.

Avoid generic-label or store-label brands because the food is probably from bulk suppliers. Do not pick products that have unidentified meat or bone meal. It's got to specify the protein(i.e. chicken, turkey, salmon).  Avoid preservatives that are controversial: BHT, ethoxyquine, BHA and propolyneglycol. Those are things you don't want to see on the label.

Make sure there are no wheat or wheat gluten products in your pet food, and monitor your pet's behavior to be sure your pet is well.