Can You Eat Moldy Bread? Here's What Food Safety Experts Say

If you buy or bake bread, you've probably found mold on your loaf at some point. That white or green fuzz is annoying and unappealing, and it’s a clear indication that your bread is past its prime. But what happens if you eat moldy bread—is it safe to eat? And is it safe to remove the moldy slices and eat the rest of the loaf? We consulted food safety experts to find the answers.

What Happens if You Eat Moldy Bread?

When it comes to bread, surface mold isn't just ugly and unpalatable; it can be unsafe. "Mold can trigger respiratory issues such as asthma and allergic reactions, which will range in severity depending upon the sensitivity of the individual," says Nicole Garrison, a nutritionist, chef, food scientist, and mycology specialist, as well as a ServSafe Manager.

It's hard to say for sure how dangerous a particular loaf of moldy bread can be to your health. "Without testing the sample in a lab, you cannot be certain that a particular mold strain will or will not produce mycotoxins, which could be fatal," says Garrison.

But it's best to play it safe and not eat bread with mold. Garrison and Gevork Kazanchyan, environmental health professor at Cal State University Northridge, agree that populations at higher risk, such as babies, young children, pregnant individuals, older people, and those with compromised immune systems, should avoid contact with mold whenever possible.

What Is Mold?

Mold is a fungal growth that forms and spreads on various kinds of damp or decaying organic matter. Mold is all over the place, and not all of it is bad. Blue cheese is blue, thanks to mold—and mold is also in bread. Spores are everywhere and can be introduced into bread at every stage of its processing. In fact, we intentionally introduce yeast (microscopic fungi) into bread for its ability to leaven, improving texture and adding flavor as a result of yeast's reproductive process, says Garrison.

Why Mold Grows on Bread

When it comes to unintentional mold, it's thanks to fungi, Garrison says. "Bread becomes moldy as a result of the presence of fungi. When fungi mature, they will produce spores; this is how fungi will spread their genetic material," she says. "It does this much like a dandelion spreads its seeds, making the genetic material easily airborne so it may reproduce elsewhere." 

"The reason why we see food spoilage in bread is if food has been warm or moist, or it has been around long enough for a disease-growing organism to grow," says Kazanchyan. "The mold would not have grown if a food-preserving environment had been maintained."

Garrison agrees, "Mold spores take hold when moisture and a food source are present, and we will say it activates the spores." The best way to prevent your bread from becoming moldy is to remove as much moisture as possible. 

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The Whole Loaf Is Likely Problematic

Kazanchyan explains that moldy bread is a sign that it is spoiled, and once food spoils, it can be hard to isolate what is most harmful. So even if it's not the mold that's the problem, moldy bread is problematic. And while you might not be able to see mold on every slice, that doesn't mean it isn't there. 

"There is a lot of microscopic activity going on that the eye cannot see. The spores are like the tip of the iceberg; the majority of the fungal growth is actually beneath the surface. By touch, you may feel slightly more density in the area where the mycelium is present. Mycelium is a web-like structure that breaks down nutrients visually, similar to the root system of a tree," says Garrison.

How to Store Bread to Prevent Mold

Generally, bread is stored at room temperature because refrigeration causes the starches in bread to recrystallize and become dry. Our experts suggest freezing bread you don't intend to eat in a day or two, rather than refrigerating it. They say freezing is best for longer storage, helping prevent spoilage, including mold, and preserving not only freshness but also flavor and texture.