Most of us like the idea of throwing away fewer plastic products. We try to remember our canvas tote bags before we leave for the store, and we’re eying our plastic food-storage bags with a more critical glance. Rather than throwing away a Ziploc or other zip-top bag after we’ve used it once, could we wash and reuse them?
Yes and no. If a plastic bag was used to marinate or store raw meat or fish or eggs, Ziploc says you should toss it, as it’s unlikely you could clean it thoroughly enough to remove every trace of bacteria. The same goes for common allergens like peanuts and shellfish, if that’s an issue in your home. Other toss-it factors include tears, holes, or issues with the zipper that would prevent the bag from being fully sealed. If none of those apply, a Ziploc spokesperson says the bags “are reusable by hand washing and thoroughly drying prior to reuse.”
Science backs that up.
“These bags are almost certainly polyethylene, and I see little risk of them breaking down into anything toxic on re-use,” Ronald Larson, a professor of chemical engineering at University Of Michigan and a member of the National Academy of Engineering, tells The Takeout. “Probably the main risk is that they are not made clean enough and bacteria would grow on food residue. But this is true of any kind of container that is reused.”
So if as long as you’re washing them thoroughly, reusing a Ziploc carries about the same risk as reusing a Tupperware.
But not all zip-top sandwich baggies are Ziploc, despite the Band-Aid-status ubiquity of the brand name.
A spokesperson for Glad, for example, tells me their plastic bags do not claim to be reusable. That’s not to say you can’t try to reuse them, but that Glad doesn’t promote them as such, probably because the bags will wear down at a certain point. (Also, not reusing them has the benefit of making you purchase more bags.)
Bottom line: As long as zip-top bags don’t have holes and weren’t used to store raw meat or eggs, go ahead and thoroughly wash, dry, and reuse them. And once they get worn down, don’t toss them! Ziploc says they can be recycled at any facility that accepts plastic shopping bags.