(This blog post by Scott Witt was published May 25, 2014, at FoodSentry.org and is republished here with his permission.)
Recent reporting on chicken jerky pet treats and possibly related deaths and illnesses in thousands of dogs is something to be concerned about, and not just because families are losing their pets for no obvious reason.
Seven years seems like a very, very long time to try and then fail to discover the cause of more than 5,000 dog illnesses and deaths from a relatively small sample of foods. This is rapidly becoming a nadir in FDA’s ability to effectively protect the food supply, even though it has access to some of the best food and veterinary scientists and labs in the world. Between April 2007 and June 2012, FDA conducted 284 tests of suspected products and came up empty. How can this be?
On its face, it would appear that FDA testing for what is wrong with chicken jerky is robust. We analyzed the 284 test results reported by FDA. We were surprised to find tests for pathogens, antibiotics and other substances that would have little likelihood of causing the observed effects on dogs. A huge amount of effort was expended on these tests over several years, to no avail.
There seems to be something missing. We can find no evidence that FDA and its contract labs have actually tested the ingredients that go into the chicken jerky treats and others. Good on them for taking the time to visit factories and talk to some people. But assurances from producers are often suspect, especially in China, where most of the chicken jerky pet treats apparently come from.
According to information FDA has made public, all testing has been on product samples. We don’t understand why this is. It seems obvious to us that a close look at ingredients and their sources would be a prerequisite to the needle-in-a-haystack approach used so far.
That is what we do at Food Sentry. We are continuing this research as we write, but we wanted to give an example of what we mean.
Think about this for a moment: Chicken is a protein product. It takes chicken feed to grow the chicken. In fact, it is the primary ingredient when growing chickens. Are there any issues with the chicken feed being used in China, or, more broadly, what contaminants have been found in chicken feed in the past?
It turns out our own investigation suggests there are many issues with Chinese chicken feed. We first examined a number of types and sources of chicken feed, their prices and availability, and the locations of chicken product manufacturing plants at various places in China. In the Beijing/Tianjin/Hebei/Shandong region alone, there are more than 350,000 chicken farms that supply chicken product manufacturers in the region. This is relevant because this highly industrialized area is significantly contaminated with dozens of industrial byproducts.
Next, we compared a number of toxic contaminants for similarity with the symptoms seen in dead and dying dogs. Among few others, chromium seems to potentially fit the bill.
One of the dirtiest industries in terms of contamination is the tanning industry. One of the many contaminants in the tanning process is chromium, which leaves a residue on the tanned product. Leather scrap is left over after the manufacturing process and, because it is relatively high in protein, it is often hydrolyzed and sold as a protein feed product.
There are literally dozens of tanning factories in the area around Hebei Province/Beijing, and many sell their leather scrap to mills that hydrolyze it and sell it as a feed product. Proximity is important in terms of source availability, but companies can source their chicken feed from anywhere. We discovered that China recently closed a large number of tanneries in the region for their failure to comply with environmental standards for effluents.
Why would anyone buy a potentially contaminated product as feed for chickens? Usually it is because the price is lower than other similar products. In this case, where chicken feed is typically about 55-60 percent cornmeal, hydrolyzed protein meal is much cheaper ($0.32/kg vs. $0.11/kg). Using it can help to decrease the cost of feeding chickens while still providing the required protein. This is an excellent example of economically motivated adulteration (EMA), an increasing concern across the entire food industry.
Back to chromium. There are two types of chromium that are of interest. First is trivalent chromium, Cr (III) and hexavalent chromium, Cr (VI). Cr (III) can be found in the environment and is the type used in supplements. Cr (VI), however, is highly toxic and it is one of the byproducts of the tanning process.
There are two studies that directly measured the transfer of hexavalent chromium from hydrolyzed leather scrap feed to chicken. Each showed Cr (VI) in the gizzards, liver, brain and flesh of the chicken in volumes ranging from undetectable to 15.04 parts per million (ppm). Most samples had detectable levels of Cr (VI).
EPA has been slow to set acceptable levels of hexavalent chromium in water, but to give you an idea of how toxic the reported numbers are, consider this: In April, the California Department of Public Health submitted a final regulation that limits hexavalent chromium to 10 parts per billion (ppb) in drinking water. The studies we found showed concentrations of more than 15,000 ppb in chicken.
Experimental animal data on exposure to hexavalent chromium are limited, but oral exposure has resulted in animals developing a range of adverse gastrointestinal, liver, kidney, immunological, developmental, neurological and reproductive effects.
FDA says they are awaiting results of toxic metal testing, and chromium is in the list, among many other metals. Unfortunately, most testing for chromium tests for total chromium and does not differentiate between trivalent and hexavalent chromium. FDA has not published details on its precise testing regime, only what it is screening for.
The point of this whole discussion is to illustrate a different approach to the problem than that which the FDA has unsuccessfully taken. We recommend thinking in terms of going back to the very beginning of the supply network, learning about the environment, performance of companies, strength of the regulatory effort and specific ingredient sources to inform a more targeted approach to resolving these kinds of issues. Don’t be satisfied with just testing samples off the shelf or samples sent in from consumers. Get to the beginning of the product’s life and look deeply. That is what Food Sentry does.