The infamous “yoga mat” chemical that Subway was forced to remove from their bread earlier this year can still be found in just about every other fast food chain’s bread, from the buns at McDonald’s and Burger King to Wendy’s pretzel buns. Also known as ADA, it’s a dough conditioner that, when baked, breaks down to a chemical called semicarbazide that’s been found to increase the incidence of tumors when fed at very high levels to female mice, but not male mice or rats. According to the FDA, it poses no threat to humans at the levels it’s currently found in food.
More commonly known as PDMS, dimethylpolysiloxane is a silicon-based synthetic polymer (so plastic, basically) that’s used as an anti-foaming and anti-caking agent and emulsifier in processed foods. It prevents deep-fryer oil from foaming, preserving its shelf life — so many fast food companies, including McDonald’s, add it to their oil. It’s also used to make cosmetics, Silly Putty, shampoos, and industrial oils, but it’s non-toxic at the concentration used in fast-food restaurants, 10 parts per million, according to the FDA.
One of the world’s most commonly made chemicals, titanium dioxide can also be found in McDonald’s honey mustard sauce and Subway’s Seafood Sensation, as a coloring. It also provides whiteness and opacity to thousands of products including paints, plastics, ink, paper, toothpaste, and cosmetics, and is one of the main ingredients in sunblock. It hasn’t been found to have any negative effects when used in small quantities in food, but it can cause cancer when inhaled in its powdered form.
Commonly known as disodium ribotides in the flavor industry (which is a thing), these nucleotides are similar to MSG in that they’re flavor enhancers. Produced by microbial fermentation via tapioca starch, they’re traditionally one of the “natural flavors” that you find on a whole lot of processed food packages. They’ve been fully approved by the FDA for food use, and can be found in everything from Wendy’s chili to Arby’s chicken tenders and Subway’s chipotle sauce.
This phosphoric acid compound is an edible phosphoric salt that’s used as a leavening agent and inhibitor of food discoloration. It can be found in the biscuits served at Hardee’s as well as everything that’s fried at Burger King, including the French fries (to “preserve natural color”). While it can cause serious inflammation in super-high concentrations because it’s so acidic, the FDA has approved it in small quantities as a food additive.
These three specific compounds (monosodium, disodium, and trisodium phosphate) are primarily used as emulsifiers (to prevent fat from separating from the rest of a mixture), and can also change the texture as well as boost the shelf life of food. They’re one of the primary ingredients in Arby’s roast beef, as well as in the turkey, ham, and roast beef served at Subway, in Hardee’s Thickburgers, and in KFC’s fried chicken, and are considered to be safe when used as a food additive.
A more purified version of cochineal extract, this red dye is derived from beetles harvested from cacti and can be found in hundreds of the foods we eat, from chewing gum to soups to yogurt and ketchup. It’s safe for consumption (just like most insects), but if it gives you the heebeegeebies, don’t order the Subway Seafood Sensation, which uses it (as well as titanium dioxide) as a coloring.
This chemical has many uses, including in fertilizer, water disinfectant, and to restore soil and groundwater after oil spills. It’s also a flour bleach and a dough conditioner, which means that it will strengthen dough and provide a good texture to the finished product. Like azodicarbonamide, it’s found in plenty of fast food baked goods, including McDonald’s buns.
MSG is probably the best-known flavor enhancer, and also the most misunderstood. It’s a naturally-occurring amino acid, giving an “umami” flavor to lots of foods. Used for more than 100 years to season food, today it’s traditionally produced by extracting amino acids from sugar beets, sugar cane, tapioca, or molasses via fermentation. It’s found in just about every food item at KFC (including the original recipe fried chicken), as well as the fried chicken and sausage at Burger King, but has been taken off of the menu at McDonald’s. While there have been plenty of anecdotal reports of MSG giving people nausea, headaches, flushing, and weakness, these effects have been replicated using a placebo, and researchers have found no link between MSG and these symptoms — though a very small percentage of people may experience a mild MSG reaction.