Some burgers that you’ve eaten might not be what you think they are. A new report reveals that more than one in ten burger brands across the US contains pathogens, unexpected ingredients, and other contaminants — including rat DNA. Food analytics platform Clear Labs identified problems with ingredient substitutions, hygiene, and contamination in 13.6% of the 258 burger products the company analyzed on a molecular level, in a report released on Tuesday.

The company analyzed ground meat, frozen patties, fast-food burger products, and veggie burger products. Some of the most jarring numbers: 4.3% of samples contained traces of pathogenic DNA, rat DNA was found in three products, and human DNA was discovered in one frozen vegetarian burger. READ MORE