Some 500 dogs and nine cats may have died after eating chicken jerky pet treats made in China, according to updated complaints logged by federal veterinary health officials.

A new tally of reports filed with the Food and Drug Administration shows the agency has received 2,674 reports of illness involving 3,243 dogs, including 501 deaths. The agency also has received reports of nine illnesses in cats, including one death, the FDA said.

That’s up from an estimated 2,200 reports of illness, 360 dog deaths and one cat death reported last summer. So far, though, FDA has not been able to confirm a link between the treats and the ailments. 

The new figures come less than a week after two of the largest retailers of pet chicken jerky treats issued voluntary recalls of several popular brands after New York state agriculture officials detected unapproved antibiotics in the products.

Nestle Purina PetCare Co. recalled its popular Waggin’ Train and Canyon Creek Ranch brand dog treats, and Del Monte Corp. officials recalled their Milo’s Kitchen Chicken Jerky and Chicken Grillers home-style dog treats from shelves nationwide.

In addition, two more firms have recalled their treats as well, including Publix stores, which recalled its private brand Chicken Tenders Dog Chew Treats and IMS Pet Industries Inc., which withdrew its Cadet Brand Chicken Jerky Treats sold in the U.S.

The voluntary recalls effectively remove the pet treats from store shelves nationwide, but FDA officials say they still haven’t solved the mystery of what’s been making animals sick. They say tests by the New York State Department of Agriculture and Markets found trace amounts of antibiotic residue, but that the levels don’t pose a threat to animals or people.

“Based on the FDA’s review of the NYSDAM results, there is no evidence that raises health concerns, and these results are highly unlikely to be related to reports of illnesses FDA has received related to jerky pet treats,” the agency said in a statement.

The New York agriculture agency used a common test to detect chemical contaminants in foods, said Joe Morrissey, a department spokesman. They relied on liquid chromatography-tandem mass spectrometry, or LC-MS/MS. The tests revealed four antibiotics not approved for use in poultry in the U.S. and one antibiotic that may be used, but is limited to nearly undetectable limits in the finished product.

FDA officials will continue to investigate animal illnesses tied to jerky treats. Since 2007, the agency has warned consumers several times that jerky treats are not necessary for pet health and that eliminating them won’t harm animals.

The agency last spring inspected five Chinese plants that made jerky treats. Officials weren’t allowed to take samples for testing. Now, inspection reports released about the fifth site, Yantai Aska of Yantai, China, shows that plant officials falsified records regarding imports of glycerin, a key component in the jerky treats.

Officials with China’s regulatory agency, the General Administration of Quality Supervision, Inspection and Quarantine, or AQSIQ, suspended the firm’s export certificate as a result of the March 2012 inspection.

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A Colorado company is refusing to recall chicken jerky dog treats potentially contaminated with salmonella bacteria, prompting federal health regulators to urge consumers to keep them away from pets.

The Food and Drug Administration warned pet owners Thursday not to feed dogs certain Nature’s Deli Chicken Jerky Dog Treats packaged and distributed by Kasel Associated Industries of Denver.

The warning is not related to the ongoing investigation of reported illnesses and deaths in pets that consumed chicken jerky treats made in China.

Kasel officials previously recalled additional lots of Nature’s Deli chicken jerky treats, Boots & Barkley Roasted American Pig Ears and Boots & Barkley American Variety Pack Dog Treats, and Boots & Barkley American Beef Bully Sticks -- bull penis treats -- after they tested positive for salmonella that could cause illness.

But FDA officials said firm officials “declined” to conduct a voluntary recall of the newly implicated treats.

The products in question are Nature’s Deli Chicken Jerky Dog Treats sold in 3-pound packages with a lot code of BESTBY061913DEN. A retail sample of the treats tested positive for salmonella in November, Colorado Department of Agriculture exams showed.

The products are sold at Costco, which has pulled them from store shelves and is working to notify customers who bought them, an FDA spokeswoman said.

No reports of illness have been linked to the treats, the FDA said.

People and animals could contract salmonella either by handling or eating the contaminated products.

Infection with salmonella bacteria typically causes short-term illness in healthy people, but can cause serious complications in those with weak immune systems.

Related stories: 

• Chicken jerky dog treats recalled by US firm over salmonella risk
• Bull penis pet treats recalled for salmonella risk
• 3 big brands may be tied to chicken jerky illness in dogs, FDA records show