Mmmmm! Antifreeze. Sounds yummy, no? Well, the Food and Drug Administration says propylene glycol, one of the chemicals used in the manufacture of your car's engine coolant is, well, cool to eat and drink, too. At least in small doses.

Propylene glycol doesn't usually make for interesting dinner conversation, but the reason it's on anyone's tongue these days is because the European bottler of the popular cinnamon-flavored whiskey Fireball announced it had accidentally shipped to Finland, Sweden, and Norway batches containing the chemical, which is more tightly regulated in Europe. What's got tongues wagging, though, is that U.S. and Canadian regulators have no such qualms about letting us ingest more of it.

Glass of whiskey with whiskey bottles in the background

Image source: Getty Images.

With all the engineering companies are performing on our food, propylene glycol is likely one of the more innocuous additives found therein. But if Fireball can make a recipe for Europe that contains lesser amounts of the ingredient, why would it want to continue selling one in North America that has more?

Fire in the belly
The Daily Beast has pointed to the whiskey's college campus popularity, and Bloomberg Businessweek cited the market researchers at IRI highlighting its phenomenal growth trajectory, noting sales have surged nearly 3,000% over the last three years, hitting $61 million in 2013. That's more in one year than either Pernod Ricard's Jameson Irish whiskey or Patron Spirits' tequila.

Bloomberg further points out that those numbers don't include sales made at bars, so they're likely even higher.

Whether news that it's made with an ingredient used in antifreeze will hurt sales now remains unknown, but we probably ingest a lot of propylene glycol and don't even realize it because the FDA has classified it as "generally recognized as safe" (GRAS), meaning it can be used as a food additive.

In a statement on Fireball's website, Sazerac says the North American recipe is not being recalled and is perfectly safe to consume, pointing out propylene glycol has been "used in more than 4,000 food, beverage, pharmaceutical and cosmetic products for more than 50 years."

And the only reason it's found in antifreeze today is due to a spate of news reports a few years back saying pets were being sickened and killed from lapping up the coolant, which contained the chemical's toxic cousin, ethylene glycol. Antifreeze manufacturers have also added bitter-tasting chemicals to the mix to stop pets, particularly dogs, from eating the slightly sweet-tasting compound.

A full plate of chemicals
But because propylene glycol is considered a safe food additive -- up to 50 grams per kilogram (and for the record, Fireball uses less than an eighth of what's permitted) -- it's found in many consumer products today.

Propylene glycol might not be the only thing you want to check the label for. Image: Breyer's Ice Cream.

Some of your favorite ice cream flavors from Breyer's and Stone Cold Creamery contain propylene glycol because it helps prevent ice crystals from developing, while Corona Extra adds it to its beer. McDonald's  (MCD -0.91%) uses it in its Big Mac, salad sauces, and bagels, and Tom's of Maine uses it as a base for its deodorants (OK, hopefully you're not eating your deodorant). And if you're smoking electronic cigarettes, propylene glycol is in the e-liquid that carries the nicotine, flavorings, and other additives, which are then heated, vaporized, and ingested.

A witch's brew
Propylene glycol is a colorless organic liquid that's manufactured by treating propylene with chlorinated water to form the chlorohydrin, which is then converted to the glycol, an alcohol, by treating it with a sodium carbonate solution.

According to the FDA, in alcoholic beverages, it shouldn't exceed 5% of the amount needed to achieve its desired effect, but no more than 24% for confections and frostings. In frozen dairy products it shouldn't be any more than 2.5%, yet it can go as high as 97% for seasonings and flavorings.

Though toxic to animals and humans if consumed in large enough quantities, industry trade groups that represent manufacturers like chemical giants Archer-Daniels Midland (ADM -1.48%)BASF, and Dow Chemical (DOW) say that since it's not available to consumers as a pure substance it's nearly impossible to actually ingest enough to be harmful.

You are what you eat
Beyond whether propylene glycol will actually kill you, the use of such unnatural ingredients in food and drink we're consuming should give us pause. Additives of all sorts have polluted the food chain, and a diet of processed foods such as those Americans are fond of eating is probably a greater health risk than the minuscule amounts of antifreeze we're consuming in a shot of whiskey.

With all the engineering companies are performing on our food, propylene glycol is likely one of the more innocuous additives found therein. But if Fireball can make a recipe for Europe that doesn't contain the ingredient, why would it want to continue selling one in North America that does?

Editor's note: Corrected claim that propylene glycol is a banned substance in Europe. Propylene glycol is authorized for use in food and beverage products in Europe but the allowable level of food grade propylene glycol is lower in Europe than in the United States.