Two of the nation’s top retailers of chicken jerky dog treats are voluntarily withdrawing several popular brands after New York state agriculture officials said they may be contaminated with unapproved antibiotics.

Nestle Purina PetCare Co. officials announced Wednesday that they’re withdrawing Waggin’ Train and Canyon Creek Ranch brand dog treats until further notice. Officials at Milo’s Kitchen, which is owned by the Del Monte Corp. of San Francisco, announced they are voluntarily recalling the firm's Chicken Jerky and Chicken Grillers home-style dog treats from shelves nationwide.

The move came after the New York Department of Agriculture and Marketing told federal Food and Drug Administration veterinary officials this week that trace amounts of residual poultry antibiotics had been found in several lots of each of the brands of jerky treat products.

The agriculture agency found very low levels of four antibiotics that are not approved for use in poultry in the U.S. and one antibiotic that is approved for U.S. poultry use, but is limited to nearly undetectable levels in the finished product, said Joe Morrissey, a department spokesman. The antibiotics include sulfaclozine, tilmicosin, trimethoprim, enrofloxacin and sulfaquinoxaline, he said.

The antibiotics are approved in China, where most of the treats are made, and in other countries, according to company statements. 

However, Keith Schopp, a spokesman for St. Louis-based Nestle Purina, said that the issue is not related to the ongoing FDA investigation of problems with Chinese-made jerky pet treats that may have sickened more than 2,200 pets and killed 360 dogs and one cat, according to consumer reports.

"There is no indication that the trace amounts of antibiotic residue is related to FDA's ongoing investigation," Schopp told NBC News. 

"Due to regulatory inconsistencies among countries, the presence of antibiotic residue is technically considered an adulteration in the United States," Schopp added.

FDA officials said they were confident that the detection of antibiotics "do not raise health concerns," and that they are "highly unlikely" to be related to the reports of pet illness linked to jerky treats that date back to 2007, according to a statement published late Wednesday.

FDA has conducted extensive testing and said it could find no toxins or other contaminants responsible for causing alleged illnesses ranging from nausea and vomiting to kidney failure and death. Officials said that the New York agriculture agency used a new, particularly sensitive test to detect the antibiotics. Morrissey said food specialists there tested the jerky treats because of "growing consumer concerns."

FDA officials reminded pet owners that jerky treats are not a necessary part of any animal's diet.

Robin Pierre, a New York pet owner, blames Waggin' Train chicken jerky treats for the sudden death of Bella, her 2-year-old pug in 2011. Pierre, who launched a petition urging companies to recall the treats, said she was pleased at the new move, but sorry that the FDA didn't act sooner.

"How many lives could have been saved if, six years ago, when there was first doubt that the safety of our companions was compromised, the FDA and all manufacturers of imported chicken jerky had issued a precautionary recall until the toxin was found?" she said in a statement to NBC News. "How much pain and suffering could have been avoided if only they had met their moral obligation six years ago and did the job the taxpayers pay them to do?"

Related stories:  

• 3 big brands may be tied to chicken jerky illness in dogs FDA records show
• China stiff-arms FDA on chicken jerky pet treat testing, records show
• Grieving pet owners take jerky treat fight to the stores

Kasel Associated Industries

Kasel Associated Industries of Denver has recalled Nature's Deli Chicken Jerky Dog Treats because of possible salmonella contamination.

An American maker of chicken jerky dog treats has recalled 2.5-pound packages of the product because it may be contaminated with salmonella bacteria that could cause illness.

Kasel Associated Industries of Denver has voluntarily pulled its Nature’s Deli Chicken Jerky Dog Treats, which were distributed through 57 Sam’s Club stores in a dozen states.

The recall is not related to ongoing concerns about chicken jerky pet treats made in China, which have not been recalled, according to the U.S. Food and Drug Administration.

This is the second recall in as many weeks for Kasel, which last month removed from market packages of “bully treats” -- pet snacks made from dried bull penises -- because of salmonella contamination.

The new recall of jerky treats was launched after routine sampling by the Food and Drug Administration found salmonella in the finished products. The firm has stopped distribution of any lots that were possibly contaminated, according to a company statement.

The product comes in a clear plastic bag with the Nature’s Deli logo and the UPC bar code 647263800208. The recall includes lot number BEST BY 091913.

The treats were distributed to stores in Colorado, Iowa, Idaho, Illinois, Kansas, Missouri, Montana, Nebraska, Oklahoma, South Dakota, Utah and Wyoming. No illnesses in pets or humans have been reported in connection with the recall, the company said.

Consumers who bought the 2.5-pound bags of dog treats are urged to return the products to the place of purchase for a full refund.

Related stories: 

• Bull penis pet treats recalled for salmonella risk 
• Pet jerky death toll: 360 dogs, 1 cat, FDA says
• 3 big brands may be tied to chicken jerky illness in dogs, FDA reports say

Rita Desollar

Rita Desollar of Pekin, Ill., has launched a petition calling for retail stores to stop selling chicken jerky pet treats from China. She believes her 8-year-old dog, Heidi, died in May after eating tainted treats.

Rita Desollar’s black minivan has become a rolling warning about the possible dangers of chicken jerky pet treats from China.

Everywhere the 57-year-old Pekin, Ill., woman goes, her car carries a poster detailing the May death of her 8-year-old German shepherd, Heidi.

Desollar says she gave the dog two pieces of Waggin’ Train chicken jerky tenders on a Wednesday and by the next Monday, Heidi was dead.

“I didn't know what it was. I just couldn’t figure out what made her so sick,” said Desollar, who turned to the computer for answers. "It was breathtaking what came up."

Desollar found dozens of news stories and blog accounts detailing government cautions about possible links between Chinese-made chicken jerky treats and illnesses and deaths in hundreds of U.S. dogs.

Manufacturers have issued no recalls for the products and Food and Drug Administration officials say repeated testing and investigation has revealed no contaminants that would lead the agency to advise pulling the treats.

But Desollar said she never saw any warnings and didn’t know about a potential problem -- until it was too late.

Outraged, the retired paralegal said she had no choice but to take matters into her own hands.

“They’re leaving a product on the shelf that can potentially harm a dog. There was no warning. There was nothing to tell me this was under investigation. They just left it out there.”

She launched a Change.org petition Sept. 5 calling for stores to pull the products voluntarily; since then it has gathered more than 60,000 signatures. She stuck the fliers on her car and ordered magnets that say “Stop the Cycle of Death,” along with hundreds of business cards that say “Beware... Chicken Duck and Sweet Potato JERKY TREATS are not safe!” 

“I leave the cards on the shelves by the dangerous treats everywhere I see them,” she said. “I have distributed over 1,500 of these cards to date and I have another order of 1,000 on the way.”

Desollar is not alone. Across the U.S., some pet owners -- frustrated by what they say is a lack of government or industry action to get dangerous treats off the market --  have started warning others themselves.

Retailers, pet treat manufacturers and FDA officials all say that there’s no confirmed connection between the Chinese-made jerky treats and pet harm, despite reports of at least 2,200 illnesses and deaths of 360 dogs and 1 cat blamed on the products since 2007.

“This is a very complex public health investigation,” the FDA’s Steven Solomon, a veterinarian and deputy associate commissioner of compliance policy, told NBC News this week. “The tests have not demonstrated significant toxicants.”

Another FDA official, Tracy DuVernoy of the agency’s Coordinated Response and Evaluation Network, told a gathering of veterinarians this summer that the complaints should be put in perspective.

“Two thousand complaints since 2007 is an incredibly small subset of the 15 million animals estimated to consume these treats,” she said, according to an account of the American Veterinary Medical Association conference. “Therefore, it seems that this may very well be some sort of intermittent issue, or it might just be an idiosyncratic reaction within that individual animal.”

Officials with Nestle Purina PetCare Co., which sells the popular Waggin’ Train and Canyon Creek brands of treats, have repeatedly said that internal testing has found no problems with their product and that the treats are safe to feed as directed.

But that hasn’t stopped consumers like Susan Nichols, 64, of Grand Blanc, Mich. She believes that jerky treats caused kidney failure in her 11-year-old Cocker spaniel-dachshund mix, Lucy, last year. So she printed up fliers that she surreptitiously leaves in stores where the products are sold.

“If I’m in Walmart or wherever, I will take my little Scotch tape out of my purse and tape it there,” she said. “It’s just a little thing I do. I’ll just slap one up.”

Jeff Zolman

Jeff Zolman, 42, of Aurora, Colo., said his 9-year-old dog, Bandit, died after eating chicken jerky treats. He asked to put up fliers at a local store, but was turned down.

In Aurora, Colo., Jeff Zolman, 42, was so distraught about the death of his 9-year-old dog, Bandit, that he, too, made posters with the dog’s picture and headed to the Big Lots store where he bought the treats he believes led to her death.

“The manager said he couldn’t post anything up unless it came from corporate,” said Zolman. “I understand where he’s coming from, but I wanted to get it out there for other people.”

Despite such consumer passion, retailers across the country have resisted calls to remove the pet treats from commerce, saying they need more than anecdotal reports to justify the action.

“We’re really sticking with the science at this point,” said Craig Wilson, vice president of food safety and quality assurance at Costco, one of seven stores specifically targeted in Desollar’s petition.

The chain is known for its aggressive food safety monitoring system, which includes stringent tests on jerky treats, Wilson said. So far, repeated examinations have revealed no contaminants that can be linked to reports of animal illness, including kidney failure and Fanconi syndrome.

“I don’t think people understand how hard Costco looks at this,” he said. “If there’s a hole in this boat, I’d like to be the guy who finds it.”

The other stores named in Desollar’s petition include Walmart, Sam’s Club, Target, Safeway, Kroger and Walgreens.

An official with Target noted that the jerky treats are the subject of ongoing lawsuits and said the company could not respond. Several consumers have sued the manufacturers and sellers of the jerky treats in lawsuits filed from California to Connecticut.

Officials with Kroger and Walgreens said those stores abide by FDA guidance on the jerky treat issue. 

"If the FDA determines that these or any products are potentially unsafe, they would contact us and we would immediately pull the product," Kroger spokesman Keith Dailey said in an email to NBC News.

Dianna Gee, a spokeswoman for Walmart, added that in addition to FDA standards, that firm requires pet treats to meet requirements of the Global Food Safety Initiative. She said the firm was not aware that any consumers had left behind fliers or cards protesting the treats, but she said shoppers with questions about the products should consult the manufacturers, the FDA or a Walmart manager. 

Officials with Safeway did not respond to NBC News phone calls and emails.

One store not named in the latest petition, PetSmart, said in a statement that the firm is monitoring FDA and manufacturer guidance. “At this time, we have no immediate plans to remove product from shelves," they said.

The efforts of Desollar and others may pay off, said Tony Corbo, a lobbyist for the group Food & Water Watch.

“Consumer pressure can be instrumental in getting these treats out of the marketplace,” he said.

“The easiest way to get them out of commerce is for FDA to issue an import alert against these products.”

For their part, FDA officials said they’re continuing to investigate the production processes at the Chinese plants that make chicken jerky and other types of jerky products. A small number of complaints also have cited duck and yam jerky treats.  

Inspections of five Chinese plants in April yielded valuable information that has led to increased surveillance, said Solomon. Next month, FDA inspectors will visit Chinese plants that irradiate finished jerky treat products to investigate whether that process is tied to the reports of illness and death. Officials are also examining the sources of glycerin used by the Chinese manufacturers to make the treats.

Desollar is glad that the government is continuing to look into the problem. But she said she’ll continue to take personal action to warn fellow pet owners about the possible danger.

“The FDA is a huge government office,” she said. “Purina is a huge corporation. I can’t walk into the FDA and say, ‘Do something.’ But I can walk into Kroger and say, ‘These treats killed my dog.’”

Related stories: 

• Pet jerky treat death toll: 360 dogs, 1 cat, FDA says
• 3 big brands may be tied to chicken jerky illness in dogs, FDA reports show
• Jerky treats from China blamed for pet deaths; owners sue
• FDA data dump shows few toxins in treats; complaints rise to 1,800

courtesy the Mawaka family

Toby, a 6-year-old Boston terrier, died in May after his owners say he was sickened by chicken jerky pet treats made in China. At least 360 dogs and one cat have died in the past 18 months after eating the treats, according to reports to the FDA.

At least 360 dogs and one cat reportedly have died in the U.S. after eating chicken jerky pet treats made in China, even as claims of illnesses tied to the products have topped 2,200, federal veterinary health officials said.

Food and Drug Administration officials this week issued the first summary of reports of pet deaths linked to the jerky treats in the past 18 months, along with the strongest suggestion to date that owners might want to avoid the products all together.

“The FDA is reminding pet owners that jerky pet treats are not necessary for pets to have a fully balanced diet, so eliminating them will not harm pets,” agency officials said in an online report.

At the same time, the FDA said it will begin testing treats to see whether irradiation of the products may have contributed to reports of treat-related problems ranging from diarrhea and vomiting to kidney failure, Fanconi syndrome and death.  

In 2009, the Australian government halted irradiation used to sterilize cat food after reports of paralysis and other problems appeared to be linked to the process. Ninety cats were sickened, of which 30 died, according to press reports at the time.

U.S. regulations allow pet food, including pet treats, to be irradiated up to a maximum of 50 kiloGrays to provide microbial disinfection or elimination of other pathogens. By contrast, most foods for human consumption are limited to far lower levels, 1 kiloGray maximum for fresh foods and 3 kiloGrays for fresh shell eggs to eliminate salmonella, for instance. The upper limit is 30 kiloGrays for spices or dry dehydrated seasonings -- except for frozen packaged meats for astronauts, which may be irradiated at levels up to 44 kiloGrays.

It’s not clear whether or how irradiation may contribute to illnesses in pets. The process is widely regarded as safe and even necessary by food safety experts such as Christina Bruhn, a researcher in food science and technology at the University of California at Davis.

Keith Schopp, a spokesman for Nestle Purina PetCare Co., confirmed that his firm's Waggin' Train brand products are irradiated. 

"This is similar to what is used in sterilizing spices, apples, tomatoes and meat for human food," he said in an email to NBC News. "The extra precaution is taken to assure pet owners the treats they buy are safe and healthy."

FDA officials indicated they would ask NASA -- which has expertise in the effects of irradiated food -- for help in their analysis.

Investigating irradiation's effects on pet treats will be the latest avenue for an agency stumped by rising reports of deaths and illnesses in pets. The treats are part of an estimated nearly 86 million pounds of pet food imported to the U.S. from China each year.

In China, people mostly prefer the dark meat of chicken, leaving a large amount of light meat products available for export. Much of that has been funneled into pet treats, including pet jerky treats that are considered the fastest growing segment of the pet food market, the FDA indicated.

Courtesy Susan Rhodes

Susan Rhodes of Port St. Lucie, Fla., believes her dog, Ginger, developed kidney failure after eating chicken jerky pet treats made in China. The Food and Drug Administration has received some 2,200 reports of illnesses or deaths tied to the treats.

Since 2007, the FDA has received growing numbers of reports of illnesses and deaths in pets fed the jerky treats. Repeated tests at FDA laboratories, at the agency’s Veterinary Response Laboratory Network, and by other animal health diagnostic labs across the country have failed to detect any microbiological, chemical or other contaminants in high enough levels to cause the symptoms in the pets.

“To date, none of the testing results have revealed an association between a causative agent and the reported illnesses,” the FDA said.

Most of the complaints concern treats made of chicken, including chicken tenders and strips, but the FDA also has cautioned consumers about treats made of duck and sweet potato and products where chicken or duck jerky is wrapped around dried fruits, sweet potatoes or yams.

The situation has frustrated pet owners who blame the deaths and illnesses of their animals on tainted treats. Several lawsuits have been filed against the firms that sell the treats and the companies that make them, including Nestle Purina, which makes the popular Waggin’ Train and Canyon Ranch jerky treat products, and Del Monte Corp., which makes popular Milo's Kitchen Home-style Dog Treats.

Last month, Food & Water Watch, a consumer advocacy group, along with pet food safety advocates Mollie Morrissette and Susan Thixton, delivered a letter to the FDA and a petition signed by 18,000 consumers urging the agency to take stronger action, including recalling the treats.

"I could not believe FDA was being pushed around by the Chinese," said Tony Corbo, the Food & Water Watch lobbyist for safe food. "That infuriated me. This is the impotent FDA."

The pet treat manufacturers have repeatedly said their products remain safe to feed as directed. The FDA has said it cannot recall products based on consumer complaints alone.

The agency sent inspectors to five plants that make pet treats in China in April, but Chinese officials refused to allow the investigators to take samples of the treats for analysis in a U.S. lab. Instead, Chinese officials insisted they be tested only in China.

The FDA released inspection results for four of the plants, but not for the fifth. In their latest update, FDA officials said one firm had falsified receiving records for glycerin, which is a primary ingredient in nearly all jerky treat products. After that inspection, the Chinese authority, the Administration of Quality Supervision, Inspection and Quarantine, or AQSIQ, told FDA it had seized products and suspended their export until the problem was corrected.

FDA officials declined to tell NBC News the name of the firm, the levels of glycerin detected or the volume of pet treats seized and banned from export. An agency spokeswoman said that information would be available only through a public records request.

For his part, Corbo said he plans to attend the last Pups in the Park event of the season at the Washington Nationals vs. Milwaukee Brewers baseball game on Sept. 22. He'll hand out leaflets warning pet owners about the dangers of jerky treats because he believes FDA isn't doing the job. 

"If the FDA wants to join me, they're welcome to," Corbo said. 

Related stories:

• China stiff-arms FDA on jerky pet treat testing, reports show
• 3 big brands may be tied to jerky illness in dogs, FDA records show
• Jerky treats from China blamed for pet deaths; owners sue

Courtesy the Mawaka family.

Elizabeth Mawaka of Hartford, Conn., has sued makers and sellers of chicken jerky dog treats, which she blames for the death of two dogs, including Toby, shown above. She called on Nestle Purina PetCare Co. officials to allow U.S. inspectors to test samples from China plants.

Chinese government officials overseeing plants that make chicken jerky pet treats blamed for thousands of illnesses and deaths among American dogs have refused to allow U.S. inspectors to collect samples for independent analysis, newly released records show.

Investigators with the federal Food and Drug Administration came away empty-handed after conducting April inspections at four jerky treat manufacturing sites in Liaocheng and Jinan, China, according to the records.

The plants make pet treats sold by the St. Louis-based Nestle Purina PetCare Co., including the popular Waggin’ Train jerky brands.

Chinese officials stipulated that FDA officials could collect samples only if they agreed to specific conditions, including a requirement that the samples be tested in Chinese-run laboratories.

As a result, “no samples were collected during this inspection,” wrote Dennis L. Doupnik, an FDA investigator who visited the sites.

In addition, the reports showed that the Chinese plants conducted either no laboratory tests or only sporadic tests of the raw materials, including meat used in treats fed to many of the 78.2 million pet dogs in the U.S.

The FDA found no significant violations and issued no citations, but warned plant owners about problems that included broken supports on metal screens, a torn gasket door on a mixer and failure to file proper paperwork to list actual treat manufacturers instead of shippers or brokers in FDA records.

That means the agency appears to be no closer to solving the mystery of about 2,000 reports of illnesses or deaths in U.S. dogs that ate jerky treats made in China, lawmakers and pet owners said on Tuesday. Despite tests of hundreds of treats in the U.S. over five years, the FDA has found no significant levels of contaminants in the products.

“It’s hard to believe the FDA would send a team of inspectors over to China without first getting a guarantee that they could bring samples back,” said Rep. Dennis Kucinich, D-Ohio, who has been tracking the jerky problem. “They’re doing nothing of consequence. The FDA’s tone-deaf on this one.”

Elizabeth Mawaka, 57, a Hartford, Conn., woman who says her two Boston terriers, Max and Toby, died after eating tainted treats, called on Nestle Purina to demand that samples be released to the FDA.

“It really comes down to the company,” said Mawaka, who is suing jerky treat makers and retailers. “We can talk all we want about China, but it’s really the company.”

However, a Nestle Purina spokesman said the inspections demonstrated no problems with the firm's products and no evidence that they’ve led to illnesses in animals in the U.S.

Keith Schopp, the firm’s vice president of public relations, said that it’s common for countries to refuse to have samples tested outside of the country of origin and that the terms of the inspection were set by the U.S. and Chinese governments, not by Nestle Purina or the manufacturing site officials.

“There was no attempt by Nestle Purina or the Chinese facilities to restrict sample collection,” said Schopp said in an email to NBCNews.com.

"Nestle Purina will continue to cooperate fully with FDA to assist its investigation," added Schopp, who has consistently said the treats are safe to feed as directed.

Tamara N. Ward, an FDA spokeswoman, said in an email that the inspections helped to identify additional areas that the agency may investigate, but there is "no evidence indicating that these firms' jerky pet treats are the cause of pet illnesses in the United States."

Ward did not respond to NBC News questions about the impact of the Chinese officials' refusal to allow FDA to collect samples. 

Last November, the FDA issued its third warning since 2007 about potentially dangerous chicken jerky treats after new reports of health problems in dogs surfaced, ranging from diarrhea and vomiting to kidney failure and death. In the months since then, the agency has been swamped with reports of animal illness. Last month, it expanded the caution to include duck and sweet potato jerky treats.

The FDA sent a letter to Chinese officials in March identifying five Chinese firms for inspection. Investigators were sent for several days to each of four plants: Gambol Pet Products Co. Ltd.; Shandong Honva Food Co. Ltd.; and Shandong Petswell Food Co. Ltd., all in Liaocheng, China, and Jinan Uniwell Pet Food Co. Ltd. in Jinan, China, according to reports posted this week on the agency’s animal and veterinary website. The fifth report is pending because of the need for additional information and will be posted later, said Ward, the FDA spokeswoman. 

The inspections were pre-arranged and supervised by officials with China’s General Administration of Quality Supervision, Inspection and Quarantine, known as AQSIQ.

AQSIQ officials refused to allow FDA inspectors to collect samples unless they agreed to “certain sampling conditions,” including having the jerky analyzed only in a Chinese government-run laboratory, or a third-party lab in China, wrote FDA investigator Doupnik. FDA investigators would have been allowed to witness the analysis, but not to remove samples.

“I was informed that FDA would not be allowed to ship any samples outside of China for testing in an FDA laboratory due to the issue of national sovereignty among other reasons,” Doupnik added.

Before each inspection, the reports indicated that Doupnik asked AQSIQ officials if their position on the sampling had changed. When he was informed it had not, Doupnik wrote that he did not ask to collect samples during the inspections.

The heavily redacted documents, known as Establishment Inspection Reports, traced the production of jerky treats from raw meat through final packaging. In each case, plant officials said they were aware of few complaints of any kind and none about the treats causing death or illness in dogs. That's despite documented FDA reports of complaints related to each site, Doupnik noted.

At the Shandong Petswell plant, an unidentified plant representative told inspectors that “it is her perception that the firm is making a good product.”

No FDA import alerts or import refusals have been issued for the firms, Ward said. However, she added that the FDA is conducting increased surveillance of shipments of jerky treats from China to provide guidance on possible products to target for sampling and analysis.

But Kucinich said that Chinese officials' refusal to release samples to U.S. inspectors should be grounds for banning the products from import -- or for a mandatory recall.

“That would do it for that product. I would pull them all off the market,” said Kucinich. “Fine. You’re done.”

Consumers have petitioned the FDA to urge Nestle Purina and other jerky treat manufacturers to recall the products. However, FDA officials have said they can’t force a recall based solely on customer complaints.

Related stories on Vitals: 

• Jerky treats from China blamed for pet deaths; owners sue
• 3 big brands may be tied to chicken jerky illness in dogs, FDA records show
• FDA data dump shows few toxins in jerky treats
• Arthur Dogswell recalls cat chicken jerky treats, FDA says

One of the nation's leading manufacturers of pet treats has issued a voluntary recall of chicken breast treats because of the potential to cause health problems in cats. The recall follows reports of more than 1,800 dogs in the U.S. sickened or killed after eating chicken jerky treats from China. 

Arthur Dogswell LLC issued a recall late Friday for its Catswell Brand VitaKitty Chicken Breast with Flaxseed and Vitamins treats because of potential contamination with high levels of propylene gylcol. High levels of propylene glycol in the treats could result in serious in serious injury to cats, according to the notice posted by the federal Food and Drug Administration. 

The Los Angeles-based firm is voluntarily recalling 1,051 cartons of the treats packed as either 10 or 50 packages per case of the Catswell Brand VitaKitty with Chicken Breast with Flaxseed and Vitamins, the company said in a press release. 

Health effects could include inducing anemia and making cells more susceptible to oxidative damage. The company said no illnesses have been reported to date. 

Arthur Dogswell LLC also produces chicken jerky dog treats made in China. The FDA has warned about treats made in China, which have been cited in more than 1,800 reports of illnesses and deaths in the United States. Friday's recall is the first associated with chicken jerky pet treats since the FDA issued a third warning about the products last November.

A Dogswell spokesman, Brad Armistead, sent an email statement to NBCNews.com late Friday that said the company hopes to return the products to the marketplace in the near future. 

"We have voluntarily withdrawn a small number of chicken products for cats. This is an isolated situation and does not affect any other products for cats or dogs," Armistead said. "We are committed to providing safe and healthy products to our customers and their pet companions."

The FDA has repeatedly said it has tested pet treats in the U.S. for the presence of many toxins, including propylene gylcol, but agency representatives said they found no levels high enough to urge a product recall. 

The VitaKitty treats were distributed nationwide via retail stores and mail order from April 13th through June 14th, 2012.
This product is packaged in a re-sealable 2 ounce orange plastic bag with a clear window. The VitaKitty Chicken Breast with Flaxseed and Vitamins lot codes affected are as follows: SEW12CH032701/03c and SEW12CH032702/03c with a best before date of 09/10/13 and 09/11/13, respectively (UPC code 8 84244 00057 2). Lot codes can be found on the bottom right backside of the package.

“We are taking this voluntary action because it is in the best interests of our customers and their feline companions,” said Marco Giannini, CEO and Founder. “We will be working with the FDA in our continued commitment to ensure that we meet FDA guidelines.”

The recall resulted from a routine surveillance sample collected by Dogswell and the FDA. The firm has ceased manufacture of the affected item, though it's not clear if that action extends to other products. 

Consumers who purchased the VitaKitty products are urged to return them to the place of purchase for a full refund. If the product was purchased online, consumers should contact the Internet retailer to pursue a specific return and refund. 

FDA officials did not immediately return NBCNews.com calls for more information about how the recall may relate to the ongoing issue of contaminated chicken jerky treats made in China. 

On the company website, www.dogswell.com, officials said that many of their products are made in the U.S., but some are made in China. It was not immediately clear where the recalled treats were manufactured. Dogswell brand chicken breast treats for dogs were among those tested by the FDA in 2007, when the agency first became concerned about reports of illness in pets linked to Chinese-made products. Those treats, tested in an FDA southwestern regional lab in August 2007, were found to be in compliance. 

Related stories: 

• FDA data dump shows few toxins in jerky treats
• Nearly 1,000 dogs now sick from jerky treats, FDA reports say
• FDA inspectors probe chicken jerky treats in China

waggintrainbrand.com

Waggin' Train chicken jerky tenders, sold by Nestle Purina Pet Care, are among top brands of Chinese-made pet treats linked to illnesses and deaths in U.S. dogs.

Newly posted results of more than five years of testing chicken jerky pet treats made in China appear to confirm assertions from government officials that they don’t know what’s making America’s dogs sick, even as complaints about the products have nearly doubled.

Federal Food and Drug Administration officials unexpectedly posted summaries this week of lab results of nearly 300 jerky treat samples collected and tested in the U.S. between April 2007 and June 2012.  To see the results, click here.

The documents indicate that FDA scientists at labs nationwide tested for bacterial contamination, for mold and for chemicals used in antifreeze, resins and plastics that can harm pets. They tested for heavy metals and for the melamine and melamine analogs detected in pet food that sickened thousands of animals in 2007.

At the same time, new FDA figures indicate that the number of complaints of animal illnesses and deaths blamed on the treats has risen to more than 1,800, according to Tamara Ward, an agency spokeswoman. 

The lab results show a mere handful of adverse findings related to the popular Chinese-made treats. None of the reports rose to the level of needing regulatory action, such as a recall, the documents indicate.

“This does not represent ALL testing that has and is being conducted by FDA,” Ward said in an email. “Additional testing is currently being conducted through other avenues.”

The FDA released the data a day after NBCNews.com reported that the agency had refused to release results of February inspections of the Chinese plants that make the treats. The agency said releasing the information would violate rules protecting trade secrets and confidential commercial information and that it would interfere with enforcement proceedings. That data remains confidential.

Pet advocates critical of the FDA said that while they welcome the release of the domestic data, the results indicate that the agency is not looking hard enough for the source of the illnesses, including hundreds of reports of vomiting, diarrhea and kidney failure.

“When I scanned down through the list of testing, they all seemed to be centered around the same handful of tests,” said Susan Thixton, who writes the blog TruthaboutPetFood.com. She believes the FDA needs to broaden its view to include other potential toxins. 

"You can't find what you don't look for," she said.

FDA covered bases, experts say
But animal health experts not affiliated with the FDA said the agency appears to be using due diligence to track the source of the problem. Tina Wismer, medical director of the ASPCA Animal Poison Control Center, said the review appears to be complete.

“Looking at what they’re testing for, I’m looking at the list of poisons that we know affect the kidneys and they’ve got their bases covered,” she said.

That’s a view echoed by Marion Ehrich, a professor of pharmacology and toxicology at the Virginia-Maryland College of Veterinary Medicine.

“From the website provided, it seems analyses of submitted samples have not yet led to the discovery of anything toxic that is consistently present in the samples,” she wrote in an email. “They have been looking at possible suspects (melamine, bacteria, molds, etc.) but nothing is standing out.”

The FDA is working to develop and validate new ways to detect toxic substances for which there are no current tests, said Ward, the agency spokeswoman.

The 284 samples included in the new data were collected after consumer complaints, as part of routine surveillance or as an assignment, Ward said. Of those, only six indicated adverse findings.

Those included salmonella found in three samples, including Dingo and Waggin Train chicken jerky products and in one unidentified product. Mold was found in a sample of Waggin’ Train jerky, too. Low levels of melamine were detected in one sample of Del Monte beef flavor jerky treats, the tests showed. Another Dingo treat had a questionable genetic fingerprint that was sent for further analysis.

In addition, a few samples were positive for undeclared propylene glycol, but not at levels that would have prompted regulatory actions, the documents said.

Most of the tests were like one posted on Aug. 20, 2007 for Waggin’ Train chicken jerky tenders. No melamine or related compounds including ammeline, ammelide or cyanuric acid was found, the test showed. No ethylene glycol or diethylene glycol -- toxic components of antifreeze -- were found.

The FDA has issued three warnings about jerky treats since 2007, including the most recent one last November. That’s a fairly strong action for an agency that typically keeps mum on investigations, said Kimberly May, a veterinarian and assistant director in the communications division for the American Veterinary Medical Association.

“This is as close as they’re going to come to saying there’s a problem,” May said. Officials with Nestle Purina Pet Care Co. and Del Monte Foods, which make the top brands of treats, insist that their products continue to be safe to feed animals as directed on the packages.

But some experts say it’s up to pet owners to be cautious.  

“At this point in time, until we figure out exactly what is going on, I probably wouldn’t feed these,” the ASPCA's Wismer said.

To report complaints about animal illness, visit the FDA’s Safety Reporting Portal.

Related stories on Vitals: 

• Jerky treats from China blamed for pet deaths; owners sue
• Nearly 1,000 dogs now sick from jerky treats FDA reports say
• 3 big brands may be tied to chicken jerky illness in dogs, FDA records show

courtesy the Mawaka family

Toby, a 6-year-old Boston terrier, died in May after his owners say he was sickened by chicken jerky pet treats made by Nestle Purina. The Connecticut family is among several nationwide suing the maker of the treats and stores that sold them.

Dog owners in eight states who believe contaminated chicken jerky treats from China sickened or killed their pets are banding together in a class-action lawsuit against Nestle Purina, the maker of two popular brands of the canine snacks, and several mega-stores that sell them.

They are suing just as Food and Drug Administration officials have refused to release results of inspections of Chinese plants that make the jerky treats blamed for at least 1,000 illnesses and deaths in U.S. pets.

“I don’t have any new information,” FDA spokeswoman Tamara Ward said in an email to msnbc.com.

The inspections were expected to shed some light into what toxins may have caused pet problems ranging from nausea and vomiting to kidney failure. Despite repeated tests, the FDA has identified no problems with Chinese-made chicken jerky treats.

In a letter dated July 5, FDA officials denied entirely an msnbc.com public records request for results of the February inspections of treat plants, saying release would violate rules protecting trade secrets and confidential commercial information and that it could also interfere with enforcement proceedings. Msnbc.com is now NBCNews.com.

The lawsuit filed in federal court expands an April complaint by Dennis Adkins, 57, of Orland Park, Ill., who said his 9-year-old Pomeranian, Cleo, died in March after eating Waggin’ Train “Yam Good” dog treats produced by Nestle Purina Pet Care Co.

It adds six pet owners in states from coast to coast who are suing not only the treat maker, but also Wal-Mart, Target and Costco, three big retailers that sell the products.

And it seeks to join with a lawsuit filed in federal court last month by a Connecticut family who believe their two Boston terriers, Max and Toby, died after eating chicken jerky treats they didn’t realize were suspect.

 “Toby was falling over and crying out in pain and we would give him another treat because we thought we were doing something nice for him because he was hurting,” said Philip Mawaka, 69, a Hartford, Conn., pastor whose wife, Elizabeth, is named as the plaintiff.

Lawyers for Nestle Purina and the three store chains said they couldn’t comment on the specifics of the suits because the litigation is pending.

“We believe the claims made in the suit to be without merit and we intend to vigorously defend ourselves,” said Keith Schopp, a spokesman for Nestle Purina and Waggin’ Train. “We can say that Waggin’ Train products continue to be safe to feed as directed.”

Three top brands of chicken jerky treats were among those most recently cited by pet owners and veterinarians in complaints of harm, FDA records obtained by msnbc.com showed. They included Waggin’ Train and Canyon Creek Ranch, brands produced by Nestle Purina, and Milo’s Kitchen Home-style Dog Treats, produced by the Del Monte Corp.

Import data compiled by the firm ImportGenius showed that Waggin' Train and Canyon Creek Ranch treats are produced and supplied by JOC Great Wall Corp. Ltd. of Nanjing, China. 

The expanded lawsuit claims to represent nearly all pet owners in the U.S. who bought any dog treat product made or sold by Nestle Purina containing chicken imported from China in the past four years, court records show.

The dog owners say they’re frustrated that the makers and distributors of the treats have failed to recall the products voluntarily, despite three federal warnings since 2007 about possible safety issues and nearly 1,000 reports to the FDA of dogs sickened or killed by the products.

They also say the companies have violated implied warranties of safety and healthfulness of their products and commerce rules governing sale of sound merchandise.

"Just because they haven't found something doesn't mean it isn't there," said Barbara Pierpont, 47, of Stewartstown, Pa. Her 7-year-old rescue dog, Honey, died of kidney failure in April, three weeks after Pierpont started giving her Waggin' Train jerky tenders bought at Sam's Club, a subsidiary of Wal-Mart. The treats were the only change in Honey's diet, she said.

In addition to Pierpont, the suit includes other pet owners from California to New Jersey:

• Mary Ellis of Ontario, Calif., who claims that the Waggin’ Train treats she bought in February sickened two of her dogs, Buster and Boomer, both 9, and killed Maggie, 12.
• Maria Higginbotham, Gig Harbor, Wash., who contends that Chik n’ Biscuit dog treats sickened her two rat terriers, Bandit, 3, and Kali, 8.
• Dwayne and Kaiya Holley of Hempstead, Long Island, N.Y., who say that Waggin' Train Yam Good treats bought from Wal-Mart led to the death from kidney failure of their 5-year-old Yorkshire terrier, Bootsie, in March.
• Deborah Cowan, Perryton, Texas, who believes chicken jerky tenders caused kidney damage that sickened her 8-year-old dog, Rowdy.
• Cindi Farkas, of Howell, N.J., who says her dog Chanel, 6, was diagnosed with kidney disease after eating one half of a treat each day for three weeks this spring. 

Those owners are among thousands calling for the recall of the chicken jerky treats and for more vigorous FDA efforts to identify the source of the problem.

“It has been way too quiet,” said Robin Pierre, 50, of Pine Bush, N.Y., who contends that Waggin’ Train jerky treats killed her previously healthy 2-year-old pub, Bella, last fall. “They [FDA officials] are not responding to anything at this point. No emails, no phone calls. Everyday there are more and more victims added to our list.”

More than 15,000 people have signed Pierre’s petition calling for the treats to be removed from the market.

Many pet owners say they're reminded of the 2007 scare in which melamine-tainted pet food from China sickened and killed thousands of dogs in the U.S., leading to mass recalls and criminal indictments of Chinese and American pet food executives. The problem was not detected immediately then, either, said Bruce Newman, the Connecticut lawyer representing Mawaka. He represented dozens of pet owners whose animals were sickened then. 

The FDA has tested for melamine and melamine analogs, along with other chemical and microbiological toxins, but found no evidence of harmful levels, said Ward, the FDA spokeswoman. The treat makers could recall the products voluntarily, but in the absence of an identified toxin, FDA officials say the agency can't force a recall. 

The FDA remains aware of and concerned about the problem, Ward said. Officials are developing new methods for testing for compounds in the jerky treats that could cause illness. It could take months to develop and validate the tests, she said.

The agency also has formed an internal task force to study jerky treats that includes players such as Costco’s Craig Wilson, vice president of quality assurance and safety.

“FDA is working and discussing with industry and retailers how we can mutually collaborate and share data, scientific exchanges, etc,” Ward wrote in an email. “We are committed to solving the problem and Costco is one of several parties interested in determining the root cause of the illnesses.”

Costco tests the jerky treats regularly at every step of production and distribution, Wilson told msnbc.com. So far, the retailer has detected nothing that could explain the reports of illness in dogs. He said FDA officials and Costco representatives will travel later this fall to the Chinese plants that make the Costco treats.

 “Our testing program is very solid,” he told msnbc.com. “We actually test these at a higher level than some human food.”

Wilson declined to comment on the lawsuit, but he said he believes government animal health experts are working hard to find the source of the problem.

“The FDA is really on this,” he said. “I applaud their efforts.”

More coverage of tainted jerky treats:

• Nearly 1,000 dogs now sick from jerky treats, FDA reports say
• 3 big brands may be tied to chicken jerky illness in dogs, FDA records show
• FDA inspectors probe pet jerky treats in China

Courtesy Robin Pierre

Bella, a 2-year-old pug, died last fall after her owner, Robin Pierre, said she ate Waggin' Train chicken jerky treats.

Nearly 1,000 dogs reportedly have been sickened by chicken jerky pet treats from China, according to a new tally of complaints from worried owners and veterinarians submitted to federal health officials.

The Food and Drug Administration has logged some 900 reports of illnesses and deaths since November, when it warned owners about continued problems with the products known variously as chicken jerky strips, treats and nuggets, a spokeswoman said.

Back then, the agency already had heard from 70 owners about problems ranging from vomiting and diarrhea to kidney failure and other serious ailments after animals reportedly consumed the treats.

Since then, complaints have mounted steadily, putting growing pressure on the FDA to solve the problem.

The agency sent inspectors earlier this year to Chinese plants that make the jerky treats, two Ohio lawmakers previously told msnbc.com.  No results of those inspections are yet available, FDA spokeswoman Tamara Ward said Monday. 

Despite repeated tests since 2007, FDA scientists have been unable to detect any toxin responsible for the animal illnesses, officials said. The agency has asked certain pet owners to send in samples of suspect treats along with their animals' veterinary records.

Three top brands of chicken jerky treats were among those most recently cited by pet owners and veterinarians in complaints of harm, FDA records obtained by msnbc.com showed. They included Waggin’ Train and Canyon Creek Ranch brands produced by Nestle Purina PetCare Co., and Milo’s Kitchen Home-style Dog Treats, produced by the Del Monte Corp.

Import data compiled by the firm ImportGenius showed that Waggin' Train and Canyon Creek Ranch treats are produced and supplied by JOC Great Wall Corp. Ltd. of Nanjing, China. 

Both manufacturers have insisted their chicken jerky treats are sound and that any illnesses are unrelated to the products.

But representatives from Milo’s Kitchen confirmed that the firm has paid at least one owner who complained about a sick dog $100 in exchange for a release of all liability.

The company examined treats submitted by the pet owner and reviewed veterinary records for the animal, according to Joanna DiNizio, a spokeswoman for the firm.

“Following the evaluation, the veterinarian consultant concluded the symptoms experienced by the pet were not related to consuming Milo’s Kitchen chicken jerky treats,” DiNizio said in an email statement.

The dog owner has declined to be identified, but Milo’s representatives said they provided the $100 as a “goodwill gesture” and asked that the consumer sign a “standard release form.” Firm officials said such arrangements are conducted on a case-by-case basis and they declined to confirm how many similar agreements are in place. 

A spokesman for Waggin' Train, Bill Salzman, said last month that the firm also negotiates agreements with complaining pet owners individually.

Such signed agreements do legally absolve firms of future claims, said Ron Simon, a Texas food safety lawyer.

“What the company is up to is to try to assuage consumer complaints without accepting liability,” said Simon.

However, he noted that in most states, pets, no matter how precious, are regarded as property with little change of recovering damages beyond the animal’s literal worth. Most lawyers probably wouldn’t accept such a case, he added.

“You don’t get mental anguish,” he added.

That’s outrageous to pet owners who believe their animals were harmed or killed by contaminated jerky treats.

Robin Pierre, 50, of Pine Bush, N.Y., contends that Waggin’ Train chicken jerky treats were responsible for the sudden death last fall of her previously healthy 2-year-old pug, Bella, who developed kidney failure. 

"Right now the laws are protecting the rights of these manufacturers and we as victims/consumers have none," Pierre wrote in an email to msnbc.com. 

Pierre is the founder of a petition to ban the jerky treats which now has logged more than 10,445 signatures.

FDA officials have said companies are free to recall the treats at any time but regulations do not allow for products to be removed based on complaints alone. 

Pet owners can submit complaints to the FDA's safety reporting portal.

More chicken jerky treat news:

• FDA inspectors probe pet treats in China
• 3 big brands may be tied to chicken jerky illness in dogs, FDA records show
• More dogs sick as FDA steps up scrutiny of chicken jerky pet treats
• Chicken jerky treats linked to mystery illnesses in dogs
• VIDEO: Dog owner claims treats killed his dog

Federal health officials have sent inspectors into Chinese plants that make chicken jerky pet treats to investigate potential links to illnesses and deaths in hundreds of dogs in the United States, two lawmakers say.

Staffers for Sen. Sherrod Brown, D-Ohio, and Rep. Dennis Kucinich, D-Ohio, confirmed Wednesday that Food and Drug Administration officials were conducting the inspections.

“Based on our ongoing discussions with the FDA, we are expecting important new information soon,” Vic Edgerton, a spokesman for Kucinich said in an email to msnbc.com.

It’s not clear exactly how many inspectors are involved or which plants the officials will visit as they attempt to solve the mystery behind at least 600 reports of illnesses including abrupt kidney failure after dogs have been fed chicken jerky treats made in China.

FDA officials declined to comment on the inspections.

waggintrainbrand.com

Waggin' Train Wholesome Chicken Jerky Tenders were among 13 Nestle Purina brand treats listed among 22 complaints being investigated by the Food and Drug Administration. The treats, made in China, have been tied to reports of illnesses and deaths in dogs.

Stumped by mysterious illnesses in at least 600 dogs in the U.S., federal health officials have turned to consumers for help investigating problems possibly tied to chicken jerky pet treats made in China.

A log of complaints collected from pet owners and veterinarians contains references to at least three popular brands of jerky treats that may be associated with kidney failure and other serious ailments, according to internal Food and Drug Administration documents obtained by msnbc.com.

Of 22 “Priority 1” cases listed by the FDA late last year, 13 cited Waggin’ Train or Canyon Creek Ranch jerky treats or tenders, both produced by Nestle Purina PetCare Co., the records show. 

Another three listed Milo’s Kitchen Home-style Dog Treats, produced by the Del Monte Corp. The rest listed single brands or no brand.

Priority 1 cases are those in which the animal is aged 11 or younger and medical records that document illness are available, an FDA spokeswoman said. In many cases, samples of the suspect treats also are collected.

The report, obtained through a public records request, is the first agency indication of any brands linked to illnesses that have climbed since the FDA warned pet owners about jerky treats in November. That was the FDA's third caution about the pet products since 2007.

Nestle Purina and Del Monte officials said their treats are safe and FDA regulators said repeated tests have shown no absolute tie to any brand or manufacturer.

“No specific products have been recalled because a definitive cause has not been determined,” FDA officials said in a statement.

The internal report, overseen by the FDA’s Coordinated Outbreak and Response Evaluation, or CORE, group, is one of several ongoing assignments in which FDA regulators are seeking jerky treat samples and medical records of dogs that may have developed kidney failure, liver disease or Fanconi syndrome, which can lead to serious illness and death.

The recent complaints were filed from October through December by people in cities from California to New York, but the agency will continue to accept them.

“We still invite owners and veterinarians to submit complaints and samples,” said Siobhan DeLancey, an FDA spokeswoman. “The more information we have, the more likely we can find a link.”

The move comes as the FDA is under growing pressure from consumers and lawmakers to address rising numbers of illnesses blamed on the China-made treats. Before the warning was issued in November, the agency had logged 70 reports of illnesses tied to the treats last year. Since then, more than 530 additional complaints of illnesses and some deaths have been filed, officials said.

Courtesy Robin Pierre

Bella, a 2-year-old pug, died last fall after her owner, Robin Pierre, said she ate Waggin' Train chicken jerky treats.

Consumers who say their dogs were sickened or killed have launched at least three petitions demanding recalls of jerky pet treats made in China, including one begun in December that has more than 3,400 signatures from the U.S. and around the world.

“At the slightest doubt, these products should have been recalled, especially knowing there was a link or at the very least a caution/warning label put on the packaging warning the consumers,” said Robin Pierre, a co-founder of “Animal Parents Against Pet Treats Made in China.”

Pierre, 49, of Pine Bush, N.Y., believes Waggin’ Train chicken jerky treats were responsible for the sudden death last fall of her previously healthy 2-year-old pug, Bella, who developed kidney failure. 

“The last week of her life was nothing but misery and pain, separated from her family, she died all alone, in a cage, despite the fact that she had a family who loved her,” Pierre wrote in an email to msnbc.com. “She meant the world to me and my family.”

Courtesy Susan Rhodes

Ginger, a 14-year-old family dog, sparked one of three petitions after she developed kidney failure possibly tied to chicken jerky pet treats. Her owner, Susan Rhodes, 51, of Port St. Lucie, Fla., wants the treats pulled from the market.

More than 375 people have signed a petition launched last week by Susan Rhodes, 51, of Port St. Lucie, Fla. She believes her 14-year-old dog, Ginger, may have developed life-threatening kidney failure after eating chicken jerky treats. She was stunned to hear that consumer complaints alone can’t force the FDA -- or a company -- to recall potentially tainted products.

“That is just unreal. I am not happy with that,” Rhodes said.

For their part, FDA officials said the companies are free to enact a voluntary recall at any time.

Lawmakers call for action
Lawmakers, however, are demanding stronger FDA action. Ohio Democrats Sen. Sherrod Brown and Rep. Dennis Kucinich in February called on the FDA to step up investigation of tainted pet treats.

In a response sent late last week, an FDA official told Brown the agency “continues to actively investigate” the reports and to pursue testing for chemical and microbiological contaminants.

On Monday, Brown called the agency’s response “inadequate” and urged prompt release of results of 153 pending tests on the Chinese-made treats.

“I will continue to press the FDA on this issue because Ohio consumers shouldn’t have to worry about the safety of their pet’s food,” he said in a statement.

Since 2007, FDA scientists have analyzed jerky treats for evidence of dangerous toxins, including heavy metals, melamine, melamine analogs and diethylene glycol, chemicals used in plastics and resins.

So far, they’ve found nothing convincing, a point emphasized by Keith Schopp, director of communications for Nestle Purina.  He noted that FDA officials also suggest that illnesses may be a result of causes other than eating jerky treats.

“Our chicken jerky treats are safe to feed as directed,” said Schopp. “The safety of our products -- and the pets who consume them -- are our top priorities.”

The company has a comprehensive food safety program in place, he said, including at manufacturing plants in China.

Pierre, who lost her dog, has little faith in pet food manufacturers -- or in the FDA.

“Actions speak louder than words and there has been no action from them up until now,” Pierre said. “Waggin’ Train has hid behind the technicality that the FDA cannot find the link and the FDA has let them.” 

Consumers can report illnesses to the FDA's pet food complaint site.

Related stories:

Chicken jerky treats linked to mysterious illness, deaths in dogs

More dogs sick as FDA steps up scrutiny of chicken jerky pet treats

Government health officials have received more than 500 reports since November of illnesses in dogs who ate chicken jerky pet treats.

Amid reports of more than 500 dogs sickened by chicken jerky pet treats imported from China, government health officials are ramping up port inspections for dangerous toxins.

Food and Drug Administration officials have begun collecting and testing chicken jerky treats upon import, analyzing samples for evidence of melamine and melamine analogs and diethylene glycol, chemicals used in plastics and resins, a spokeswoman said.

Melamine-tainted imported pet food sickened and killed thousands of dogs and cats in the U.S. in 2007, leading to massive recalls and criminal indictments of Chinese and American pet food executives.

So far, FDA officials have found no evidence of harmful levels of melamine or other substances in the chicken jerky treats, said spokeswoman Tamara Ward. But the agency has increased its surveillance of the products, even as repeated chemical and microbial tests have failed to reveal a source for illnesses that continue to mount.

FDA now has received 537 reports of illnesses in dogs, including 467 reports since it issued a renewed warning about chicken jerky treats from China in November. That number includes 353 reports logged in 2011 and 184 submitted so far this year, Ward said.

Pet owners and veterinarians are reporting that animals have been stricken with a range of symptoms within hours or days of eating chicken jerky treats, including serious problems such as kidney failure and Fanconi syndrome, a condition marked by low blood sugar.

The illnesses appear tied to imported Chinese chicken jerky products, also sold as chicken tenders, chicken strips or chicken treats.

FDA scientists have worked for months to detect a source of illnesses, Ward said. Samples have been tested for drugs, poisons and mycotoxins, as well as for heavy metals and certain chemicals.

Still, the source of the problem remains a mystery and no specific brands or products have been named or recalled in connection with the illnesses, FDA officials said.

The November warning was the agency’s third alert about chicken jerky treats in four years. Previous cautions were issued in 2007 and 2008. In 2007, 156 reports of dog illnesses tied to chicken jerky were logged, but the number fell sharply, to just 41 in 2008, according to FDA reports.

Consumers can report suspicious illnesses to the FDA’s Pet Food Complaint site.

Related stories:

Chicken jerky treats linked to mystery illnesses in dogs

Chicken jerky treats sicken 353 dogs, owners report

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