Some ground beef samples and vegetarian patties were found to contain pathogenic DNA, rat DNA and even human DNA, according to a recent report provided by Clear Labs.

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The lab sampled over 250 food products, including fast-food burgers, ground beef and other products from 79 brands and 22 retailers. The testing included verifying whether ingredients listed on the labels matched what was found in the product. Other testing examined whether the nutrient information found on the packaging accurately reflected the nutrients within the product.

According to Fortune, nearly 14 percent of the samples were problematic. In some samples, the meat had a presence of DNA from cheaper products, such as chicken or turkey. Pork DNA was found in one sample of beef patties and in another sample of ground beef, which might be an issue for those who avoid certain meat for religious purposes.

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Nearly one in four vegetarian products were found to have problems. In two cases, meat was found in a vegetarian product and more than a dozen products were missing ingredients that were listed on the packaging, including a black bean burger that contained no beans.

One of the most disturbing results from the testing was the presence of both rat and human DNA in food product samples. Rat DNA was found in three products, one of which was vegetarian. Human DNA was found in only one sample, also a vegetarian product.

Clear Labs suggested that the presence of DNA from humans was most likely caused by hair, skin or fingernails accidentally mixed during the manufacturing process.

In the report, Clear Labs says:

"While unpleasant, it's important to note that it is unlikely that human DNA or rat DNA is harmful to consumer health. What many consumers don't know is that some amounts of human and rat DNA may fall within an acceptable regulatory range. The amounts we detected in our research most likely fell within the acceptable regulatory range as we understand them."

Rat feces is likely the source of the contamination of the affected products, according to Clear Labs.

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The tested burgers and vegetarian products were selected from retailers and fast-food chains in northern California, according to Fortune.

Read more here.