Time, yet again, to reassess your dog's diet. A growing number of dry dog foods are being recalled in the wake of a discovery of Salmonella contamination at a Diamond Pet Food facility in South Carolina.

Unlike the melamine-in-pet-food scandal that killed hundreds of dogs and cats in 2007, this tainted dog food hasn't resulted in any illnesses of pets yet, but it has sickened 14 people in nine states, due to contact either with dogs or dog food. Five of those people have been hospitalized.

The recall, which started last month, now involves 13 brands of food distributed mostly in the Eastern U.S.:

- Wellness Complete Health Super5Mix

- Canidae Dog

- Natural Balance

- Diamond Pet Food Chicken Soup for the Dog Lover's Soul

- Diamond Pet Food Country Value

- 4Health

- Diamond Professional

- Diamond Premium Edge

- Diamond Naturals

- Diamond Taste of the Wild

- Kirkland Signature Super Premium

- Kirkland Signature Nature’s Domain

- Apex Chicken and Rice Dog

For complete recall info, including lot numbers, visit diamondpetrecall.com.

Read more: Backyard chickens: Cute, innocent, delicious ... and deadly?

Diamond hasn't released any information as to the source of the Salmonella, whether it was the meat or another ingredient, which makes it difficult for pet owners to know which ingredients on the label should raise red flags when it comes to product safety. "It could be an ingredient, it could be the equipment," says Robert Downey, owner of the holistic dog-food brand Annamaet. "Not too long ago, a pet company had to recall their product because it was the packaging that tested positive for contamination."

Just like processed human food, dog food is made with ingredients from dozens of sources, says Downey, who also has a background in veterinary nutrition from the University of Pennsylvania School of Veterinary Medicine. And quality varies greatly. Between two products with identical ingredients lists, one could contain poor-quality cuts of meat with a higher potential for contamination, while the other product could contain high-quality ingredients that have been rigorously tested. Yet, government regulations restrict what pet food manufacturers can print on their packages, making it nearly impossible for you to determine which one is the higher-quality pet food.

Read more: 5 healthy, homemade dog treats

But that doesn't mean you still can't find healthy pet food. Downey recommends that you look for three specific things whenever you're shopping for a new dog food:

1. "Byproducts." "Avoid anything that says byproducts," he says. They're usually waste products, like necks, feet, intestines and feathers (in the case of chicken) that can carry a potential for contamination. For instance, some organ meats not immediately refrigerated after an animal was slaughtered for humans are considered unfit for human food but OK for use in dog food. Look for foods that list specific meats, as well, such as "chicken" or "chicken meal" rather than "poultry" or "poultry meal." Generic labels usually indicate meat from a variety of sources.

2. "Analysis." Every dog food bag is required to list a nutrient analysis that breaks down the food's protein, fat, fiber and moisture content. It doesn't give you many clues as to Salmonella contamination, but it can give you some sense of product quality. Here's what Downy recommends looking for under each term.

Protein — Aim for a protein content of 23 percent for older adult dogs, 26 percent for active dogs, and 30 percent if you're buying a grain-free dog food. Don't be tricked into thinking protein contents higher than 32 percent are better for your dog. Dogs physically can't utilize protein in contents higher than that, he says.

Fat — Pet obesity is a huge problem, pun intended. "Close to 60 percent of dogs in this country are overweight," he says. So a low-fat dog food is key. A normal-weight dog of any age should eat a food with 10 to 15 percent fat, and one trying to lose weight should eat food with 8 to 10 percent fat. "More important, though, is the ratio of fat to protein," Downey says. If you're eating a food on the low end of the protein range, it should also be on the low end of the fat range.

Fiber — "I've always believed in low-fiber diets," he says. They're healthier for dogs. So aim for a food with 3 to 4 percent fiber.

Moisture — Although this is required on dog food labels, most dry dog foods have the same moisture content, about 10 percent, says Downey.

Read more: Weight loss secrets for fat cats and plump dogs

3. Where it's from. Is it a small family owned company or a big conglomerate? "A lot of the good, smaller dog food companies have been bought out by the big boys," he says. "But are they maintaining the quality?" Downey says a number of small regional brands of dog food exist that are superior to the major national brands. Though it's not always a guarantee, smaller companies tend to have a better handle on quality control.

This story was written by Emily Main and originally appeared on Rodale.com. It is reprinted here with permission.

MNN tease photo of kibble: Shutterstock

Shopping for a new dog food? Here's what you need to know
It's hard to avoid Salmonella in dog food, but not unhealthy ingredients. Here's what you should look for and what you should avoid.