Sorry, but There’s No Such Thing as the “Clean Part” of Moldy Bread

We’ve all been through this scenario: You get hungry, stroll over to the kitchen, and decide you’ll make the perfect sandwich, layered with your favorite deli meat (or veggies), a slice of lettuce, some tomato, a dab of mayonnaise (which is not dead for this millennial), all in between your favorite sliced bread.

But what do you do if you pull out a packaged loaf and discover it has a teeny little bit of mold at the top? Do you take it and slice off the bad part and go on with your sandwich fantasies? Do you toss that slice, and maybe the next one down for safety’s sake, and then continue with your lunch dreams? Or do you go for the low-carb option and toss that whole loaf away? Unfortunately science suggests you stick with the third option.

Last week YouTube channel Science Insider released a video about what’s going on with the mold on your bread, and why under no circumstances should you eat any of that bread. “That seems so wasteful!” you may be saying, just like I did before I watched host David Anderson’s enlightening video.

You might not know this, but mold has a part that you can see, and also a microscopic part that you can’t see.

That’s right. The video uses a great analogy of mushrooms growing in a forest. The part any human can see, the caps that grow above ground, are actually joined by an underground network of microscopic roots called hyphae. That’s also what is probably happening in your sliced loaf of seemingly fine-looking bread, which is why you should not eat the moldy slice, nor any of the slices it was hanging out with in that warm, growth-friendly bag.

“But what about cheese? We eat that even though it’s moldy!” is what my mother, an avid save-the-loafer said when I told her to stop doing this immediately. While it’s true that mold grows on cheese, it’s a different, benign sort of mold. Blue cheese mold is actually beneficial to the body, and the types in blue, penicillium roqueforti and penicillium glaucum, have natural antibacterial properties and an ability to overtake pathogens in your body.

In contrast, some of the molds that develop in bread are poisonous and sometimes lethal, because they contain mycotoxins. For instance, Rhizopus stolonifer is commonly called black bread mold and can cause intestinal infections if ingested. It’s also one of the first kinds of mold to develop on bread when it turns, which makes it one of the most common of the over 100,000 types of food molds that exist. I’m not even sure with that many types how an expert would differentiate the safe mold from the unsafe kind.

So, essentially, don’t take your chances: Toss that loaf and make a salad instead.