By now, we've all heard the horror stories about what goes into hot dogs, from sodium nitrate and erythorbate, to an ever-changing list of mystery meats (pig rectum!). As America continues to gear up for barbecue season, we were hoping hamburgers would remain the safer bet. But it turns out burgers, including more health-conscious veggie patties, are full of enough accidental ingredients to make your stomach churn. 

Food analytics company Clear Labs released a new study this month titled “Under the Microscope,” which examined 258 frozen, fresh and fast-food samples from 79 brands and 22 retailers. And while Clear Labs co-founder Mahni Ghorashi told Eater that the rate of “serious problems” the company found was actually lower than anticipated, the results of the study are in, and they’re still horrifying.

Clear Labs

Once thought to be a healthy alternative to the standard, all-American beef patty, it turns out veggie burgers are perhaps in the worst shape of all.

“Of the 89 vegetarian products we sampled, 23.6% were problematic compared to a problematic rate of just 13.6% for the total 258 samples,” the study reads. “While vegetarian burgers often acted as an alternative to meat, their growing popularity has solidified their stake as a burger category in and of themselves. With consumption on the rise, it’s more important than ever to fine-tune and diligently adhere to safety standards.”

What does it take for a burger to become “problematic” exactly? Most shockingly, rat DNA and human DNA were found in one vegetarian sample. And while the thought of consuming rodent may put you off burgers for life, according to the study, “the presence of human DNA or rat DNA is not likely to be harmful for human health.” Traces of DNA can be acceptable in terms of federal regulations, and the contamination is likely to occur when skin, hair, or fingernails (or rats) get mixed in during the manufacturing process.

Clear Labs

“Safe cooking is the one thing that's in the control of the consumer—as long as you cook it properly, you likely won't get sick because you'd at least be eating cooked rat DNA," Shelley Feist, executive director of temperature at the Partnership for Food Safety, told Eater. Rat DNA was also found in one fast-food burger and one ground meat sample. “The element might still be in the food, but the bacteria and pathogens will be killed."

As if vermin-infested burgers weren't enough, Clear Labs also found veggie items that contained beef, as well as a self-professed “black bean burger” that contained no black beans.

[via Eater]