So you went on a shopping spree at the grocery store last week, stocked up on more fruits and veggies than you normally do, and kept some of them in your fridge for longer.

Now, you opened the fridge, only to see that some of them had caught mold. What should you do? Do you have to throw those moldy food items away, or are they still safe to eat?

Moldy foods in your fridge, with a few exceptions like dry salami and blue cheese, are generally unsafe to eat and should be discarded of immediately. This is because they produce spores and mycotoxins, which can agitate your allergies and make you sick.

Penicillium, the mold that grows on the casing of dry-cured salami and gives Roquefort, Gorgonzola, and Stilton cheese their distinct aroma and flavor, is different from the black molds that grow on most other foods in your fridge when they start to rot.

Unlike them, Penicillium won’t produce toxins that can get you sick. So what are those black molds, exactly?

It’s hard to determine just how many species of fungi exist, the USDA’s Food Safety and Inspection Service says on its website. Estimates range anywhere from tens of thousands to 300,000 or more.

There’s no single type of mold specifically called “black mold,” most people use the term to refer to Stachybotrys chartarum. Also known as S. chartarum, this type of mold tends to favor the moisture and warmth of most households over the harsher conditions out in the open.

Other molds commonly found in households include Alternaria, Aspergillus, Botrytis, Cladosporium, Fusarium, Geotrichum, Monilia, Manoscus, Mortierella, Mucor, Neurospora, Oidium, Oospora, Rhizopus, and Thamnidium.

Scientists have a hard time determining the exact number of molds out there. And, if they’re in your fridge, it’s hard-to-impossible to decide on which kind you actually have.

One thing’s for sure: you don’t want them on (and in) your food. Molds produce mycotoxins, toxic organic compounds potentially harmful to your health when ingested in large quantities.

Why Does Mold Grow in the Fridge?

The short and sweet answer is that your fridge provides a humid, mostly dark, and not overly cold environment that’s ideal for mold growth.

Molds reproduce through airborne spores, which can easily spread in your fridge as it circulates the air inside it. Since they like moisture, one moldy food item can quickly contaminate others and even lead to mold growth on the shelves and walls of your fridge.

The good news?

Cleanliness can help you to prevent that from happening.

To inhibit mold growth in your fridge, turn the following two things into a habit:

Store food items prone to rotting separately in airtight Ziploc bags or Glasslock food storage containers.

Clean out your fridge every few weeks. Sanitize the walls, shelves, and drawers every 2-3 months with a solution of 3 teaspoons of bleach in a quart of water (in this concentration, bleach is effective at killing mold on non-porous surfaces).

For mold growing in tiny holes and small corners, use a cleaning spray like RMR-86.

Which Foods Are Prone to Catching Mold?

Fruits and vegetables with a higher moisture content, such as citrus fruit, tomatoes, and cucumbers, are more susceptible to mold than their low-moisture counterparts as they can be contaminated below the surface.

For a longer list of fruits and vegetables to avoid when moldy, check out Medical News Today’s roundup of the top 20 most hydrating foods.

This rule of thumb also applies to packaged goods like milk, cream, yogurt, non-blue cheeses, butter, peanut butter, and jams, as they hold a high amount of liquids. As well as soft and porous baked goods like bread, pizza crust, cake, pie, and cookies, Business Insider reports.

When is it okay to cut out the mold and eat the fruit or veggie in question? 

Only when you’re talking about food items lower in moisture content, like puffed carrots, celery stalks, and all-purpose potatoes, which still have some firmness to them.

Unpleasant odors and excessive mushiness are typically signs of decay and bacterial growth; don’t ignore them.

How Dangerous Is the Mold in Your Fridge?

Okay, so you saw a few moldy strawberries in the refrigerator. What’s the big deal?

Is this something you can turn a blind eye to and ignore for a while, at least until you find the time (and crank up the will) to clean it out?

Health experts advise otherwise.

Mold in your fridge is a problem not only because it looks icky but because, as Mayo Clinic explains, breathing in its reproductive spores can cause allergic reactions for you and your family members, especially those with a history of allergies.

If you see moldy food, the best thing to do is get rid of it immediately and check the other items in your fridge for mold. Don’t try to smell it, as you can inhale mold spores that trigger your allergies. For extra safety, wrap the moldy items tightly in plastic wrap before throwing them in the bin.

Can Mold Spread From One Food to Another?

The short answer is yes, mold can (and very often does) spread from one food item to another. Once it has infected a single food item, the fungi that we call mold will start to release airborne spores that can easily land on other foods, the walls and doors of your fridge, and even your kitchen sink.

Uncovered foods are more likely to catch fold than those stored in plastic bags or food storage containers. So it’s a good practice to keep food items tightly sealed and well compartmentalized in your refrigerator.

What Temperature Will Kill Mold?

Mold can be difficult to remove for a reason; your house provides a warm and humid environment for it to grow in.

Most molds have a hard time growing below 40°F, thrive between 77°F and 86°F, and are typically destroyed at temperatures above 140°F. However, some molds produce heat-resistant spores that can survive high heat, including the heat treatment of pickled vegetables (yet they need access to oxygen to grow).

This is why the U.S. Food and Drug Administration (FDA) recommends refrigerator temperature to be below 40°F, though frequently opening the door can raise the internal temperature of your fridge well above that level.

In Conclusion

Thanks for reading this far! Moldy food items in your fridge, as you know by now, are dangerous, as they can agitate your allergies and, in extreme cases, make you sick.

Do the responsible thing for yourself and your family by immediately discarding them. And what’s good for the environment by throwing them in the compost bin (yes, moldy food is okay to use in it).