Tracing the untraceable: why contaminated jerky is still on the shelves

When a food product sickens - or worse, kills - consumers, authorities don’t rest until the cause of the contamination is found and action taken to prevent it happening again. Pet owners would like to think that these same standards would apply if food produced for their furry friends made them sick. But a product that is suspected to have sickened thousands of pets in the US alone is still on the shelves.

The reason this product - chicken jerky, sold as treats for dogs and cats - hasn’t been withdrawn from sale is that the authorities have no idea what the contaminant is.

Thus far, 3600 dogs and 10 cats in the US have been affected by the jerky, with 580 deaths attributed to the product, the US Food and Drug Administration (FDA) says. And these are just the reported cases. While the FDA has identified jerky products generally as the common factor in these cases, it is stumped as to exactly what it is that’s in the jerky that’s causing these pets to perish.

Detecting the undetectable

“This is one of the most elusive and mysterious outbreaks we’ve encountered,” said Bernadette Dunham, director of the FDA’s Center for Veterinary Medicine (CVM).

Since the first reported cases in 2007, the CVM has reportedly conducted more than 1200 tests for microbiological contaminants, heavy metals and elements, pesticides, rodenticides, moulds, antibiotics and other compounds. It has gone as far as visiting jerky treat manufacturers in China in an attempt to track down the cause.

Unfortunately, because no one particular contaminant has been identified, a recall of the suspect products has not been issued in the US. While several US companies have voluntarily recalled their products after they were found to contain traces of unapproved antibiotics, the manufacturers said such minute quantities of antibiotics were unlikely to have caused such widespread issues.

In Australia, dried pigs’ ear and vegetable chews have also been implicated in cases but, to make things even more baffling, some of the sick dogs have no history of eating commercial treats of any kind, Dr Linda Fleeman, author of a paper on the topic that was published in the Australian Veterinary Journal, told VIN News.

“I am aware of several cases in Europe that were not associated with treats but responded to diet change,” Dr Fleeman said. “It might be preferable to change the focus from ‘pet treat’ to ‘food associated acquired proximal renal tubulopathy’.”

The FDA has narrowed down the list of suspected culprits to treats sold as jerky tenders or strips made of chicken, duck, sweet potatoes or dried fruit. Within hours of eating these treats, affected pets exhibit symptoms such as decreased appetite, vomiting, diarrhoea, increased water consumption and/or increased urination.

Severe cases have involved kidney failure, gastrointestinal bleeding and a rare kidney disorder.

“Most of the jerky treats implicated have been made in China,” the FDA said in a statement. “Manufacturers of pet foods are not required by US law to state the country of origin for each ingredient in their products.”

Collaborative research

The FDA has issued a call to veterinarians and the public to report any suspected cases of pet illness or death due to jerky in an effort to gather as much information about the situation as possible. Vets across the US have been requested to contact the CVM with details of any animals they suspect have been sickened or died after eating jerky.

An FDA-developed fact sheet has been made available at veterinary clinics, pet supply stores and other locations frequented by pet owners that similarly urges consumers to get in touch with the CVM if they suspect their pet has been affected. It also outlines the symptoms to watch for and what to do with uneaten jerky treats if a pet appears to have become sick after eating them.

“We hope that these tools will help prevent more pets from becoming sick and will provide us with the clues we need to crack the case,” vet Linda Tollefson, associate commissioner for FDA’s Office of Foods and Veterinary Medicine, wrote on the FDA blog.

In particular, one piece of information that the FDA is lacking is lot numbers of the suspected products. “If we have the lot numbers, we can identify whether particular lots triggered more complaints, trigger products back to specific manufacturing facilities and identify lots for testing,” the agency said in a statement.

The mystery continues Down Under

The mystery of what’s in the jerky isn’t limited only to the US: cases have also been reported in Australia.

According to Dr Fleeman, cases of renal illness in dogs started appearing after chicken jerky treats became available in Australian stores.

Dr Fleeman and fellow researchers reviewed cases of 108 dogs in Australia who developed kidney disease after consuming Chinese-made chicken jerky treats, VIN News has reported. One in three of the affected dogs recovered without medical treatment once their owners stopped feeding them the jerky, the researchers found.

“We unfortunately did not have follow-up information for all 108 cases and so do not know for certain whether or not they all recovered after the treats were discontinued,” Dr Fleeman told VIN News.

“However, anecdotal information is that almost all 108 cases recovered with discontinuation of treat feeding. I feel certain that we would have received feedback if the dogs had not recovered as expected.”

In Australia, the cases seem to be linked to a range of KraMar chicken jerky dog treats, which were recalled in 2008 and 2009. However, Dr Fleeman told VIN News, several other products have been implicated, including dried pigs’ ears from Australian-raised pigs.

“Unless a complete diet history is obtained each time a case is diagnosed, there will be a risk of attributing blame or causation to a variety of individual treats and missing data that will help establish true associations,” Dr Fleeman told VIN News. “It is also important to clearly demonstrate resolution of the problem following diet change.”

Despite her research, Dr Fleeman admits that she knows no more than the US authorities.

“After the AVA (Australian Veterinary Association) issued an alert to members, the media picked up the story and the treats were recalled from the market, but we haven’t ever been able to discover a definite cause for the problem,” Dr Fleeman said in an AVA statement.

“We don’t really know what’s currently happening in these cases. Some seem to be associated with other dog treats, while a number seem to be linked to pigs’ ears.”

While the Great Mystery of the Chicken Jerky continues, vets are recommending pet owners avoid jerky products altogether - or feed with caution - until more is known about what’s causing the problem.

Even though pet owners are taking responsibility for their pets’ wellbeing by avoiding the suspect products, some are calling for action to ensure that incidents like this don’t occur again.

“The Obama Administration needs to release the proposed rule on preventive controls for animal feed, including pet food, under the FDA Food Safety Modernization Act,” said Wenonah Hauter, executive director of Food & Water Watch.

“This proposed rule has been held up by the Office of Management and Budget for nearly two years.”