Imagine if your beloved dog suddenly became seriously sick or even died. That’s bad enough. Now imagine finding out that the cause of his illness may have been the food you’ve been feeding him every day. That’s even worse.

In the past several years, there have been a number of recalls — many voluntary — of pet food found to contain various toxins, including the bacteria E. coli and salmonella. Most recently, two class action lawsuits were filed against a major manufacturer of pet food claiming that one of its most popular products contains substances that have sickened or killed thousands of dogs. The ingredients in question are propylene glycol, a synthetic chemical used in antifreeze; mycotoxins, fungi that grow in cereal grains; and menadione, an artificial form of vitamin K approved for animal feed. Menadione has been linked to liver toxicity, allergies and the breakdown of red blood cells.

Related: The Truth About Salmonella and Your Pet

“Those are just the substances we know about,” says Victor Dasaro, DVM, of the Newburgh Veterinary Hospital in Newburgh, New York. “There may be others. There aren’t many studies being done, largely because of financial constraints, and there’s little analysis of the products in this industry.”

With so little to go on, how do you make sure the food you’re serving up to your pup is healthy for him — and safe for both of you? (Humans can pick up bacterial infections from handling contaminated pet food.) Some tips for choosing the best food for your dog.

Look for AAFCO on the label

This is the seal of approval from the Association of American Feed Control Officials, a voluntary membership organization of local, state and federal agencies that regulate animal feed and drugs. “Essentially the AAFCO is an outside laboratory that analyzes food for companies and certifies that what’s on the label is really in the food,” says Dasaro. “In the supermarket the bags that have the AAFCO seal of approval are few and far between because usually only the bigger companies have the cash flow to have their products tested.”

AAFCO’s website contains information on pet food ingredients and how to report a pet food complaint to the Food and Drug Administration, which regulates the animal feed industry. (Yes, pet food is considered animal feed.)

Buy American

One of the major dog food recalls in the United States was of a product made with wheat  gluten from a single Chinese company that contained two contaminants: melamine, which is not FDA-approved for food, and cyanuric acid, used as a stabilizer in pool chlorine. Together the two are even more toxic than either alone and may have caused hundreds of dogs to die from renal failure. It’s best to feed pets only food and treats that are made in the USA.

Reject raw foods

The raw diet is trendy now, but just a glance at all the salmonella and E. coli outbreaks from contaminated meat and produce on the Centers for Disease Control website will tell you that the U.S. food chain isn’t totally safe, either. Cooking foods tends to kill bacteria.

Related: 10 Foods You Should Never Feed Your Dog

Be wary of health hype

Don’t assume that a food that claims to be free of grain, corn or gluten is better for your pet. “Unless your pet is allergic to one of these ingredients, he should be fine eating them,” says Dasaro. “On the other hand, you want to look for quality ingredients, like meat.” Be aware, too, that even so-called “hypoallergenic diet” pet foods may contain ingredients that an animal could be allergic to. Again, let the AAFCO label be your guide.

If you’re feeding your dog a food that doesn’t meet these standards, or if your pup shows signs that his kibble is upsetting his stomach, go ahead and switch to a different food but take it slow, advises Dasaro. Without changing the total amount of food you put in your pet’s bowl each day, gradually add more and more of the new food and less and less of the old over the course of two weeks. And  check with your veterinarian about any concerns you have regarding your doggy’s diet. 

Related: 8 Common Cat-Feeding Mistakes to Avoid

Denise Foley is a veteran health writer and a former contributing executive editor at Prevention magazine.