A company that uses genomic analysis technology to get information on the contents of food has found an unusual additive in a very small percentage of hot dogs: human DNA.
The report found 2 percent of 345 hot dogs and sausages sampled contained human DNA, which was classified as a "non-harmful contaminant," according to Clear Food, the company behind the test.
Two-thirds of the samples that tested positive for human DNA were vegetarian products, and 10 percent of vegetarian products tested contained traces of meat, the study found.
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Clear Food found about 14 percent of hot dogs tested were "problematic in some way." In its report, Clear Food defines "problematic" products as having substitute ingredients or hygienic issues.
Clear Food's report doesn't specify how human DNA ended up in the products or which brands were affected. Its founders said the test, which included food from 75 brands purchased at 10 retailers, doesn't identify where the DNA came from, but is aimed at promoting better food quality.
"We cannot actually say the source of the DNA," said Clear Food co-founder Sasan Amini.
More than 100 years ago, Upton Sinclair's novel, "The Jungle," claimed that unsanitary meatpacking plants allowed human body parts to make their way into meat products, spurring some of the United States' meat inspection and food quality laws.
Andrew L. Milkowski, an adjunct professor at the University of Wisconsin specializing in meat science and muscle biology, cautioned that the human DNA identified in Clear Foods' study may have simply been a result of regular handling or imperfect lab procedures.
"There are a whole lot of technical questions that I would ask about this. Did they really have good laboratory practices and avoid cross-contamination?" Milkowski wondered. "With this type of technology, it's key, because you’re amplifying tiny, tiny amounts of DNA."
Asked about the study's methodology, Amini said each sample was processed twice, in duplicate, and that any unexpected results were checked again with the original sample.
Clear Food identified other problems with the samples, including meat ingredients found in the food but not listed on labels, an absence of advertised ingredients and meat products in vegetarian items, the report describes. Milkowski said he'd like to know more about Clear Food's methodology.
"No system is perfect, but supervision of meat products... that’s under USDA Food Safety and Inspection Service," he said. "Ingredients that you can put into foods are vetted by USDA and FDA before you can even put them in, and mislabeling and misbranding is a serious federal offense."
Clear Food said many of the 75 brands tested, both large and small, scored well overall, according to the company's algorithm. The products were ranked based on how closely their actual contents matched their labels, the report explains.
Clear Food's top 10 major hot dog brands include:
- Hebrew National
- Simply Balanced
- Boar's Head
- Oscar Mayer
- O organics
The five highest-scoring hot dogs include:
- Taverrite's Mild Italian Pork Sausage, which sells for $5.99 at Safeway
- 365 Mild Italian Chicken Sausage, available for $5.99 at Whole Foods
- Aidells Organic Smoked Chicken Sausage, Spinach & Feta, available for $8.99 at Whole Foods
- Ball Park Smoked White Turkey Franks, available at Target for $3.89
- McCormick Grill Mates Smoked Sausage, Mesquite available at Walmart for $3.48
According to the report, there is no correlation between the food company’s overall score and the cost of the hot dog, meaning pricier products are not necessarily higher quality.
Milkowski, for his part, said he's "skeptical" of the results. He noted that Clear Food's sample size is "extremely small" and may not represent national offerings.
"I would have to take this with a big grain of salt as to whether they have accuracy or not," he said of Clear Food.
Clear Food released the study as part of a Kickstarter campaign to fund a food-analysis system that would rate food products based on how closely the food's genetics sequencing matches its ingredient list. The money will help pay for a run of 10 reports on different kinds of foods. The campaign was three-quarters of the way to its $100,000 goal on Monday.
"We think that consumers are ready for better food quality," and that the information in the report helps customers "insist on the best brands" at their supermarkets, co-founder Mahni Ghorashi said.
Hot dogs also made headlines Monday when the World Health Organization said processed meat, including hot dogs, may cause cancer.
The full Clear Food report is available online.
Correction: Because of an editing error, an earlier version of the story misstated the amount of human DNA found in vegetarian products in Clear Food's study.
NBC's Ari Mason and Asher Klein contributed to this report.