We’ve all been there: discovering mold on a forgotten piece of bread or a container of berries. Beyond the initial disgust, it’s natural to wonder about the potential health consequences. The question, “Will Mold On Food Make You Sick?” is a common one. What happens if you accidentally ingest mold? How much mold is too much? And what about foods like blue cheese, which are intentionally moldy?
Let’s explore the science behind mold growth on food, the potential risks of eating it, and practical tips to keep your food mold-free and safe.
What Exactly is Mold?
Molds are microscopic fungi, related to mushrooms and yeast, that thrive in moist environments, explains Josephine Wee, Ph.D., an assistant professor of food science at Penn State University. They’re a natural part of our environment and can be found virtually everywhere where moisture and oxygen exist, according to the U.S. Environmental Protection Agency.
These fungi spread by producing tiny cells called spores. “The spores are everywhere; they are on our skin, in the air that we breathe, on our foods,” says Wee. While molds play a vital role in breaking down organic matter outdoors, indoor mold can lead to food spoilage and should be avoided on damp surfaces.
“Molds grow in the right conditions. … They like higher humidity and warmer temperatures,” says Wee. Refrigeration slows down mold growth, but doesn’t eliminate it entirely.
Randy Worobo, Ph.D., professor of food microbiology at Cornell University, explains that molds also need oxygen to grow. This is why cheese and other high-moisture foods are often vacuum-packed, as mold can quickly develop once exposed to air.
“One of the unique characteristics of molds is that they’re really good at growing on just about anything. … They’re scavengers,” says Worobo. Even in the refrigerator, mold can eventually appear on forgotten leftovers.
Identifying Harmful Molds: The Good, the Bad, and the Toxic
When it comes to mold, not all types are created equal. “There’s the good, the bad and the ugly,” aka toxic, says Wee.
“Good” molds are intentionally used in the production of certain cheeses. For instance, penicillium roqueforti is used to create blue cheeses like Roquefort, Gorgonzola, and Stilton. Penicillium camemberti gives Camembert and Brie cheeses their characteristic white mold surface, explains Worobo.
The mold found in and on these cheeses is safe for consumption, according to the U.S. Department of Agriculture. “These are intentionally added to the milk cultures,” says Wee.
“Bad” mold, on the other hand, grows on food due to spoilage, says Wee. Food mold exhibits a variety of colors and textures. On bread, it might appear as green or black spots, while berries often develop a white, cotton-like fuzz. Mold on citrus fruits can look like green or gray dust.
Mold can also be red, pink, or orange, with the color changing based on the mold’s life cycle, adds Wee.
The Impact of Eating Mold: What Happens When You Ingest It?
In most instances, accidentally eating food with mold will not cause any harm, experts assure. “When you ingest the mold, the acids in your stomach, as well as the digestive enzymes, will break the cells down,” says Worobo. Generally, healthy individuals will not get sick from a few bites of moldy food.
“For the general population, it’s not a big deal,” Worobo adds.
However, immunocompromised individuals face a higher risk, as mold can potentially colonize and cause fungal infections. They should exercise extra caution and avoid any mold.
Furthermore, certain types of mold – the “ugly” ones – can produce mycotoxins under the right conditions, says Wee. These toxins can make anyone sick and pose serious health risks.
Exposure to toxic molds can lead to both short- and long-term adverse health effects, according to the World Health Organization. Aflatoxins are among the most dangerous mycotoxins and can be carcinogenic to humans, according to the USDA.
Because it’s impossible to identify the type of mold or its toxicity simply by looking at it, it’s best to avoid eating moldy foods whenever possible.
Mold Exposure and Sickness: How Much is Too Much?
The quantity of mold consumed also plays a role. Small amounts of mold are unlikely to cause illness in the average person, according to experts. However, consuming larger quantities can result in nausea or stomach upset.
People naturally avoid spoiled food, limiting the amount of mold they ingest, Wee explains.
“You’re not going to eat a slice of moldy bread because it does not taste good and it’s not appealing to the eye. It’s a sensory issue,” she says, adding that moldy food may have a bad smell or an earthy flavor, like dirt.
People will likely spit the food out or discard it before finishing it, Wee notes.
Even small amounts of any type of mold can cause problems for individuals with mold allergies, experts warn. While this often occurs through inhalation, eating mold can also trigger a reaction. “Even though there are no toxins that are present, there are people who cannot eat even small amounts (of moldy food) because of the spores,” says Wee.
Symptoms of an allergic reaction to mold can include sneezing, a runny nose, or an itchy throat, according to Mayo Clinic.
Ingesting large doses of certain mycotoxins can cause acute poisoning or life-threatening liver damage, according to the WHO. Fortunately, this is relatively rare.
Can You Salvage Moldy Food by Cutting Around the Mold?
The visible mold on food is often just the tip of the iceberg, experts caution. Think of the roots of a tree growing underground, says Wee.
The body of mold consists of thread-like roots that invade the food, a stalk that rises above the food (which may not be visible), and spores that form at the end of the stalks, according to the USDA. The spores are what you see growing on the food.
Therefore, cutting out the mold may not eliminate it entirely. Slicing a knife through a moldy spot can actually spread the spores to other parts of the food, warns Worobo.
Moldy, spoiled foods may also contain unseen bacteria that can cause illness. To err on the side of caution, discard any food with mold growth or that has come into contact with moldy food, says Wee.
When to Seek Medical Attention After Eating Mold
If you’ve accidentally eaten moldy food, don’t panic. Unless you are immunocompromised or consumed a large quantity of mold, you will likely be fine. However, it’s important to monitor for any symptoms, experts advise. If you feel well, you can proceed as usual.
Seek medical attention if you develop severe gastrointestinal symptoms or signs of an allergic reaction, such as shortness of breath, elevated temperature, vomiting, or wheezing, according to the Cleveland Clinic.
If you have any concerns or questions about eating mold, consult your healthcare provider.
Preventing Mold Growth on Food: Practical Tips
You can take steps to minimize your exposure to mold spores and prevent mold from growing on your food, according to experts and the USDA:
- Discard any food exhibiting mold growth.
- Avoid sniffing moldy food to prevent inhaling spores.
- Thoroughly clean any surfaces and containers that have come into contact with moldy food.
- Refrigerate all perishable items at 40 degrees Fahrenheit or lower.
- Store and refrigerate cooked food within two hours of serving.
- Cover food during serving to prevent exposure to airborne spores.
- Consume or discard leftovers within three to four days.
- Inspect all food for signs of mold before purchasing.
By understanding the risks associated with mold and following these preventative measures, you can protect your health and keep your food safe.
