It’s one of those food safety questions that doesn’t seem to go away: Is aluminum foil safe for cooking and storing meals? How about those metal tins? Here, USDA and FDA experts weigh in.
Photo: Getty Images
| Credit: Getty Images

Whether you’d heard that you could contract botulism by cooking food in aluminum foil or you’ve been worried about metals migrating into your food, aluminum foil safety concerns crop up periodically. What’s fact and what’s a myth? We reached out to the USDA and FDA to get to the bottom of your questions.

Marianne H. Gravely, MS, the Senior Technical Information Specialist at the Food Safety and Inspection Service of the USDA who staffs the meat and poultry hotline and has given us lots of great tips, thinks some fears about aluminum foil stemmed from a 1994 botulism outbreak involving baked potatoes. Some digging revealed that 30 people got sick after eating a potato-based dip at a Greek restaurant where staffers had “held” baked potatoes wrapped in aluminum foil for some time at room temperature. The problem here was not the foil, however; a study concluded that “toxin formation resulted from holding aluminum foil-wrapped baked potatoes at room temperature, apparently for several days, before they were used in the dips.”

This, said Gravely, was a food safety situation; those potatoes should have been put in the refrigerator or served fresh from the oven, not held at room temperature, since staffers had created a perfect breeding ground for bacteria by not storing the potatoes at the correct temperature.

Another question she frequently encounters is whether aluminum foil is safe to put in the microwave. “It’s best to avoid using aluminum foil in the microwave but it’s OK in small amounts,” she says, adding the important caveat that you need to keep an eye on it! Often people will want to cover part of a small piece of poultry with foil to avoid its overcooking, but there is a risk of “sparking,” so “don’t go off to feed the dog,” says Gravely, and watch your microwave closely. (For a deeper dive into general microwave safety, check out this USDA link!)

And if you’re worried about aluminum migrating from tins you’re cooking in the oven, such as casserole dishes, know that the FDA is not. We reached to them, and they emailed,

“Historically, the FDA has not objected to the use of aluminum metal as a food contact surface, including for use in cooking, on the basis that no more than an insignificant amount of the aluminum would migrate to food. Aluminum metal, such as that used to make cookware, reacts rapidly with the oxygen in air to form a thin, protective surface coating of alumina, which renders the aluminum corrosion resistant and less likely to migrate to food. The FDA’s position remains that the normal dietary intake of aluminum—whether from food or the use of aluminum cookware—is safe.”

They also added, “Consumers should follow the manufacturer’s instructions on food packaging labels for information on proper product use in the refrigerator, oven, or microwave.”

So that tin of lasagna from your neighbor? Probably oven-safe.

Additionally—laughs Gravely, “I’ve answered this question for almost 30 years,”—yes, you can store food in the fridge covered with aluminum foil. Occasionally, she says, “you’ll see pitting on the foil where the food came into contact with it,” especially if you’ve made something acidic, such as pickles. “It’s just something that happens from time to time,” she says. “If you can see a bit of foil on the food you can certainly cut that away, but it’s not going to make the food harmful.

Lastly, you can use the shiny side or the plain side, folks. “Doesn’t make any difference,” says Gravely. “Both sides work the same, it’s just which side came off the roller.”

Alex Van Buren is a food and travel writer living in Brooklyn, New York whose work has appeared in, Bon Appétit, Travel & Leisure, New York Magazine, Martha Stewart Living, and Epicurious. Follow her on Twitter and Instagram @alexvanburen.