The ingredient you'd be surprised to find in the Subway breakfast sandwich you're eating

Consumers tend to understand that typically, some degree of preservatives will be found in many of the processed foods sold in grocery stores. However, it could be surprising for some to find out that even fresh foods made at restaurants can contain preservatives. For example, the breakfast sandwich at Subway, which is comprised of a flatbread, cheese, egg, and an optional protein like steak, ham, or bacon (via Subway), contains propylene glycol, which is an artificially-made ingredient that helps to absorb excess water (via Food Network). 

The scary part: propylene glycol has other uses, including the lubrication of machine parts, and it's an ingredient in deodorant and antifreeze. If this isn't enough to put you off Subway breakfast sandwiches, there are almost a dozen additional additives or preservatives contained in the "premium egg blend" that the restaurant chain uses (via Forbes). This list includes TBHQ (tertiary butylhydroquinone), which is also found in varnishes and perfumes, and dImethylpolysiloxane (say what?), which while used to prevent cooking oil from foaming, is also an ingredient in Silly Putty!

More additives you'll find in Subway breakfast sandwiches

We're not done. The Subway egg blend also includes glycerin, a solvent which can also be found in personal hygiene products like soap, shaving cream, and some moisturizers. Calcium silicate, which is also a sealant used in roofing and for other construction purposes, is used in the blend to prevent caking. Appetizing? Not so much, right?

While it might stand to reason that adding preservatives and additives is the norm for fast food restaurants, it turns out that Subway is a "winner" in this category when it comes to their breakfast sandwich. Hardee's, for example, uses only a single preservative in its eggs and it's only citric acid, which can be found naturally in citrus fruits like lemons and limes (via Healthline). And quick-stop restaurants like Panera also offer fresh egg sandwich options — in fact, Panera is petitioning the FDA to more clearly outline what can be counted as an actual egg in sandwiches like what is offered up on Subway's menu (via Shape).