A couple of years ago, buying chicken jerky treats for dogs almost certainly meant buying a product made in China.

Today, dog-snack aisles of the nation’s leading retailers are dominated by packages featuring prominent “Made in USA” labels, often accented with American flags.

Whether feeding dogs jerkies made in America rather than China will make a difference to their health, though, is an open question.

“I … don’t think we know that jerky treats made in the U.S. are safe, do we? But we keep specifying Chinese-made products,” Dr. Jennifer Larsen, a veterinary nutritionist, wrote recently on a message board of the Veterinary Information Network (VIN), an online community for the profession and parent of the VIN News Service.

“Until we more fully characterize this problem and can determine any treat as safe," said Larsen, an associate professor of clinical nutrition at the University of California, Davis, Veterinary Medical Teaching Hospital, "I will continue to recommend against using jerky treats regardless of country of origin."

The safety of jerky treats for dogs has been in doubt since 2007, when the U.S. Food and Drug Administration (FDA) began hearing from dog owners and veterinarians about animals becoming ill, some fatally so, after eating chicken jerky made in China.

The FDA has searched since then for a contaminant that would explain the illnesses and deaths but come up empty. Cases continue to arise, including some that implicate duck and sweet potato jerkies. The agency’s latest tally of jerky-related complaints found more than 5,600 dogs affected — over 1,000 of whom died — plus 24 cats and three people.

Meanwhile, an ample selection of jerky products remains on the market. However, consumer pressure has pushed stores and vendors away from Chinese production. The shift climaxed last month with announcements from Petco and PetSmart, the largest pet specialty chains in the country, that they would phase out within a year all made-in-China comestibles for cats and dogs.

The declarations marked the culmination of years of growing public mistrust of all pet food and treats made in China. Suspicions about the quality of imports from China date to the melamine calamity of 2007, when tens of thousands of animals were sickened, some lethally, by eating pet food contaminated by dishonest Chinese suppliers.

Despite the resulting distaste for Chinese-produced pet foods, it was nearly impossible until recently for a shopper looking for dog treats to avoid items made in China. According to Lisa Stark, a spokeswoman for Petco, more than 90 percent of treats five years ago were Chinese imports.

Whether the “made in China” part is responsible for the apparent problem with jerky is unproven.

“Are we seeing more of these cases (of illness) from jerky treats from China simply because that’s where all of them (were) made?” Larsen mused in an interview. “Or are we seeing a problem with the Chinese manufacturing process? I think it’s too early to say.”

Pet-treat makers and retailers say they are switching to domestically made treats not for safety reasons but to satisfy consumer preferences.

“Our consumers said that they really wanted to see products made in the United States, with no ingredients sourced in China,” said Chrissy Trampedach, a spokeswoman for Big Heart Pet Brands, formerly Del Monte Foods. “We decided to make a commitment to do that. It’s a choice we made based on consumer wants and needs.”

Big Heart sells the jerky brand Milo’s Kitchen. The line was made in China until last year, and is produced now with American poultry in the United States.

Nestlé-Purina PetCare, another major seller of treats, opted to continue producing its Waggin' Train brand Chicken Jerky Tenders in China, although it switched from multiple suppliers and manufacturers to a single suppler and single factory for tighter control, according to company spokesman Keith Schopp.

Milo’s Kitchen and Waggin’ Train were among several brands recalled by manufacturers in January 2013 after the New York State Department of Agriculture and Markets Food Laboratory detected illegal antibiotics in the jerkies. Although the drug residues aren’t believed to be responsible for the illnesses, their presence is not allowed.

Big Heart and Nestlé-Purina instituted manufacturing changes upon returning jerkies to the market this year.

Although some Nestlé-Purina production remains in China, the company recently introduced two products — Jerky Duos and Smoky Jerky Snacks — made in the United States from domestic ingredients, Schopp said. “We wanted to give consumers a choice,” he said.

Schopp explained that chicken tenders are made from breast meat, which is more readily available in China owing to a preference of the Chinese palate for dark meat. Conversely, dark meat is more readily available in the United States, Schopp said, so Waggin' Train U.S.-made jerky varieties for dogs contain dark meat.

A second brand of chicken jerky made by Nestlé-Purina called Canyon Creek is being phased out “for marketing reasons,” Schopp added. He acknowledged that Canyon Creek jerky was similar to Waggin’ Train jerky. “It was pretty much a name thing,” he said.

Figures from the Pet Food Institute, an industry trade group, suggest the American dog treat market is increasingly lucrative. Marketers sold $2.6 billion in dog treats in 2013, more than double the sales in 2000.

The demand for U.S.-made pet treats, in addition to influencing owners of established brands to alter their manufacturing practices, has opened the market to new brands. Delca, owner of think!dog brand, has a new line of jerkies made of creatures from Louisiana bayous — alligator, crawfish, shrimp and crab.

From the meat to the bag it’s packaged in, the product is sourced and made in America, said Delca spokesman Flynn Baglin.

A decade or so ago, Delca made pet treats in China — not jerkies but hard treats such as biscuits and cookies, Baglin said. The company became dissatisfied with conditions there. “We found it was unstable, and it was low quality and high risk,” he said. Asked to elaborate, Baglin said he could not be more specific because the treats were private-label products that remain on the market. “Some of the factories just had lower quality-assurance that we could not tolerate,” he said.

As a maker of a variety of pet products, from cat scratching posts to puppy training pads, Delca continues to manufacture some items in China. Baglin said China is extremely efficient at producing small plush toys, for instance. But Delca is striving to bring as much manufacturing as possible to the United States, Baglin said, a goal it achieved recently with poop bags. The switch required inventing machines here. “Businesses are ready to do it,” Baglin said “They’re ready to make deals happen.”

The Federal Trade Commission (FTC) oversees the use of made-in-USA claims, providing guidance to marketers about how to make the claim truthfully. The agency advises that those who promote products as “made in USA” must meet what is known as the “all or virtually all” standard.

The Association of American Feed Control Officials (AAFCO), which develops model state laws and industry guidelines on animal feed and pet food, offers this elaboration: “… the product should contain no — or negligible — foreign content. So just putting together ingredients inside the U.S. is not enough. Additionally, just getting ingredients from a broker within the U.S. is not enough. If ingredients are imported, then it is very difficult to justify the use of the phrase ‘Made in the USA.’ ”

Julia Solomon Ensor, an attorney in the FTC Bureau of Consumer Protection’s Division of Enforcement, said any questions or complaints about such labels on pet foods and treats would be reviewed in tandem with the FDA, the federal authority on food and drug labels.

Ensor noted that the majority of complaints about U.S.-origin claims come from competitors of companies making the claims. “The consumer has very little ability to analyze on his or her own whether the claim is true or not,” she said. “Usually the person in the best position to know whether it’s true or false is a competitor.”
 
The sometimes complex nature of food processing can make clear labels hard to apply. Case in point from the human-food side: A decision last summer by the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service cleared the way for poultry from the United States to be sent to China for processing, then returned for sale to the American market.

In an article about the decision, the New York Times reported that no USDA inspectors would be present in Chinese plants, and that poultry processed there wouldn’t require country-of-origin labeling. (Whether and when such processing may occur is unclear. Food Safety News reported late last year that China has yet to certify any plants to process chickens for export, and that American companies have not expressed interest in sending poultry to China for processing.)

In a similar twist, pet-food products made domestically may contain imported ingredients. Megan Bensette, a spokeswoman for the FDA Office of Foods and Veterinary Medicine, noted that no requirement exists for a package to list the source of each ingredient. “We recommend that consumers contact the company to verify the origin of ingredients if they are seeking products that contain only U.S.-sourced ingredients,” Bensette said.

Susan Thixton, founder of the website truthaboutpetfood.com, did just that, and posted the results of her inquiry. More than one pet-food manufacturer acknowledged obtaining ingredients such as vitamins and minerals from a variety of foreign countries, including China.

In deciding to eliminate products made in China from store shelves, Petco and PetSmart put themselves in a position to act as arbiters of the label. But Petco doesn’t plan to assume that role. “We’re not doing any kind of major verification,” said company spokeswoman Stark. “We just expect that our vendors are providing us with what they say they’re providing us with.”

PetSmart, for its part, will have “ongoing conversations with our vendors” to ensure they’re following the “all or virtually all” standard, said company spokeswoman Michelle Friedman.

While Petco and PetSmart are the largest pet retailers to drop Chinese-made treats, they’re not the first. Dr. Meghan Ellis, a veterinarian in Sanford, North Carolina, who operates a pet store, remarked on a VIN message board: “Lots of independents have already stopped carrying these items. Who wants to risk making a customer’s pet sick?”

Before stocking a treat brand, Ellis said she verifies its origins by asking manufacturers directly. “If they don’t answer, they’re out,” she said in an interview by email.

Ellis asks not only where a product is made but where its ingredients come from. “‘Made in USA’ only means the final product is manufactured here,” she said. “The ingredients can be from anywhere, including the dreaded China.”

She chooses to carry only products made and sourced in the United States, Canada, Australia or New Zealand. “These are countries that have at least USA standards for pet-food manufacturing,” Ellis said.

One type of product can’t be found in Ellis’s store no matter where it was made: jerky. “Since we don’t know what is causing the illness, I feel more comfortable not selling the treats,” she said.

Ellis compared jerky to grapes, which are toxic to some dogs for unknown reasons. “Some dogs eat grapes their entire lives and they’re fine. Another dog eats one grape of the same kind and goes into kidney failure, and we have no idea why,” she said. “So we say, ‘Don’t feed your dog grapes.’ Makes sense to me.”