A moldy fruit is no reason to discard the rest; meats or breads, yes

If I open a fruit box and one is moldy, do I need to throw the entire box away?

Fresh strawberries, blueberries and blackberries are among America’s favorite fruits, but their lifespan can be fleeting. A few days after bringing them home from the fair or the supermarket, it is common to find that a gray or white fluff has taken over some berries, leading many to wonder: is it safe to eat the others?

Food safety experts say that while you shouldn’t eat obviously moldy fruits, those with no visible signs of spores are fine to eat. And luckily, unlike other food safety concerns that may be invisible to the naked eye, mold on berries is easy to spot, said Benjamin Chapman, a professor and food safety expert at North Carolina State University.

(Botanically-minded readers may note that many fruits commonly known as berries, such as strawberries, raspberries, and blackberries, are not true berries, but we’ll treat them that way for simplicity.)

If the package is stained by a moldy berry or two, “don’t throw it all away,” Chapman said. Instead, he recommends discarding molds and carefully examining neighbors for fluff, which often appears around a bruise or where the stem attaches. The rest are good to eat right away, because lingering mold spores can spread and develop more fluff in a day or two.

Molds or molds are a type of fungi that, under a microscope, often “look like skinny mushrooms,” according to the US Department of Agriculture. They create threadlike roots that invade the interior of the food and small spore-covered stalks on the surface. Certain types of fungi produce toxins that can be harmful if ingested and, in some people, can trigger allergic reactions, Chapman said.

The good news for berry connoisseurs is that the fungi commonly found on berries “are not actually known to produce toxins like some others, and so there’s less risk,” said Elizabeth Mitcham, professor and director of the Center for Post-Bullet Technology. Harvest from the University of California at Davis. Foods that generate more dangerous fungi include nuts, grains and apples, she said.

Because berry mold is generally harmless, even accidentally eating a moldy berry — although it’s not recommended — likely won’t make you sick, Mitcham said. Also, “you’d probably spit it out before you swallow it” because moldy berries “taste really bad,” she added.

Mold is a common enemy of fruit growers and traders, so it’s not surprising to find it in your berry crate, Mitcham said. Mold spores are ubiquitous in the environment. They can be transported by air or water and live in the soil of agricultural fields.

Spores normally infect the flowers or fruits of a berry plant and then lie dormant until the fruit fully ripens. Given enough time, these spores eventually germinate and can spread to adjacent fruit, especially in warmer temperatures, Mitcham said.

Because mold spores are so widespread, they can be present in small amounts in most of the fresh produce you eat. “I’m probably consuming mold spores all the time, and they’re not making me sick,” Chapman said.

Fungi become more dangerous as they grow and penetrate deeper into the food product, where some types produce toxins.

While this is usually not an issue with berries because of their shape, small size, and types of molds that grow on them, it is a bigger concern with larger foods that are moist or have a soft or porous texture, such as leftover meat or stir-fries. jams and jellies, soft cheeses and breads. If there’s mold on the surface of these foods, you should assume they’re contaminated and throw them away, according to the US Department of Agriculture.

Before buying berries, inspect them carefully and avoid buying if they have signs of mold, Chapman said. At home, do another quick check and remove any fruit that is visibly moldy. Then refrigerate the rest as quickly as possible, Mitcham said. Don’t wash the fruit until the moment you plan to eat or cook it, because moisture encourages mold growth, he added.

Spores can settle and survive on surfaces, so it’s a good idea to clean your fridge regularly “to break the mold spore cycle,” Chapman said.

The Department of Agriculture recommends cleaning the inside of the refrigerator with a tablespoon of baking soda dissolved in a liter of water every few months. And if you discover food that is “extremely moldy” in the fridge, it’s a good idea to clean it right away to prevent spores from spreading to other foods, he added.

Translated by Luiz Roberto M. Gonçalves