What Is It?
Mold is a type of fungus made up of tiny spores that float through the air. Spores are microscopic reproductive particles that allow mold to spread and grow when they land on damp surfaces. When these spores land on food in warm, moist environments, they begin to grow into visible colonies. Mold does not just grow on the surface, but it often sends thread-like roots called hyphae deep into the food. These roots can spread far beyond what you can see, which means that even if you cut off the moldy part, the rest of the food might still be contaminated. This means that what you see is only a small part of its structure! In addition, moldy foods may also have bacteria that are not visible growing with the mold.
Structure
Under a microscope, mold looks like thin, branching mushrooms. Its body has three main parts: thread-like roots that grow into the food, a stalk that extends above the surface, and spores that form at the ends of the stalk. The spores give mold its color and allow it to spread when they become airborne. The roots can grow deep into the food, which makes the mold difficult to remove completely.
Environment
Most molds thrive in damp or humid areas and can grow on a wide variety of foods such as bread, fruits, meats, and dairy products. Mold reproduces by producing spores. These spores are very small and light, so when they dry, they can float through the air. If they land on a surface with enough moisture and warmth, they can begin growing again, creating new mold growth. On bread, it looks like fuzzy green dots, on cheddar it is white dust, and small velvety circles on fruits.
Is It Harmless?
Certain molds produce toxic substances called mycotoxins, which can appear in foods such as grains, nuts, fruits, and vegetables. These toxins can cause a range of health problems, including nausea, vomiting, stomach cramps, and, in some cases, more serious effects like liver damage or immune suppression. For this reason, fuzzy spots that appear unexpectedly on bread, fruit, or leftovers in your fridge are not safe to eat! Even if you cut off the visible mold, microscopic filaments may still remain, which makes the food unsafe. However, some molds are safe and even intentionally used in food production such as those that create blue cheese or salami.
What Are The Exceptions?
Dense foods like hard cheese, firm fruits, or firm vegetables may sometimes be saved. In these cases, you can cut off at least one inch around and below the moldy spot, making sure the knife does not touch the mold itself. This only applies to firm, low-moisture foods. For anything soft, wet, or spongy, it is best to throw it away. Remember that even small amounts of mold can hide deeper in the food than you think.
Mold Prevention
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Clean the inside of the fridge every few months.
- Keep dishclothes and sponges fresh and clean because they can spread mold around your kitchen.
- Ensure that your fridge is set at a cold temperature, which is between 3 to 4 °C.
- Always buy small amounts of food and use it quickly.
A simple rule: if you see mold, do not overthink it and just toss it!
References:
https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/molds-food-are-they-dangerous
https://health.clevelandclinic.org/what-happens-if-you-eat-moldy-food
https://ucfoodsafety.ucdavis.edu/sites/g/files/dgvnsk7366/files/inline-files/26438.pdf
