What happens when two eighth grade girls and 2 ½ year old cheeseburgers and fries meet at a science fair? The young ladies come in first place after demonstrating the meals’ unchanged appearance, proving fast food contains too many preservatives.

In October of 2014, Catherine Goffard and Ava Van Straten, who entered the Notre Dame Academy Science Fair in Wisconsin, stored several fast food cheeseburgers and fries in open jars at room temperature. Two and a half years later, the results showed that slight molding only occurred in one cheeseburger, whereas the rest of the food had no bacteria growth. They young ladies compared the fast food meal to a healthier cheeseburger and fry meal that was prepared using local products. After letting the healthier meal sit for one week, it was found to be entirely covered in mold.

There was a reason why the girls were interested in this food experiment that exposed how preservatives can affect foods. “We want them to know what’s in these burgers that causes them to not mold, and how they’re unhealthy to eat,” said Ava.

Catherine added, “It makes you kind of think, like, ‘What am I actually eating?’ because there are so many other things that are not included in their ingredients list that are definitely dangerous for you.”

Over the last decade, lots of stories have been written about the after lives of fast food meals. Here’s a breakdown of some of the preservatives that can be found in the very popular fast food meal of burger and fries:

TBHQ

French fries can sometimes keep their crispy look because of TBHQ, which is a simpler way of referring to tertiary butylhydroquinone. TBHQ is a petroleum-based substance used to stop fats and oils from oxidizing, but TBHQ is also used in butane lighters, lacquer and varnish. Children are more prone to experience nausea, vomiting and tinnitus, or hearing loss, when exposed to this substance.

Calcium Sulfate

Hamburger buns stay mold-free thanks to ingredients like calcium sulfate. It is usually listed among most fast food restaurants’ nutritional data information, but it doesn’t mean it isn’t a questionable ingredient to include in a food product. This crystalline powder is white, odorless and more commonly used for vehicles, plastics, metal and pesticides.

Additives

Many hamburgers contain as little as 2 percent meat and instead contain ingredients normally found in hamburgers like blood vessels, nerves, plant material, cartilage and bone. These beef patties are also high in fat and cooked at high heat, which helps it to lose moisture, thus helping to give it a longer shelf life. Sometimes, a wide variety of additives are used to preserve and texturize the meat, like sodium phosphate and nitrates. Sodium phosphate is considered generally safe but it can disrupt how your body absorbs iron, calcium and magnesium and is not recommended for people with kidney problems. Eating too many nitrates has been linked to a variety of cancers including colorectal and stomach cancers.