Is bread mold harmful if ingested?

Updated November 21, 2016

Mold grows on a variety of foods including bread, cheese, jelly and meat. However, many types of mould contain dangerous mycotoxins if ingested. Simply cutting away the area of mould on bread is not safe. Ingesting or inhaling mould spores can cause serious allergic reactions in some people. Even animals can have adverse reactions when eating mouldy bread.


Molds are comprised of microscopic fungi that are made of millions of spores. These spores are transported on the air or by water to infect areas of high moisture. Once the fungi find moisture, they begin to grow. Mold growth is common on bread and is made up of a stalk, spores and root threads that run throughout the food it is growing on. Root threads can run deeply inside the food and may be accompanied by invisible bacteria that can make those who ingest it sick.


Mold can grow on bread in the refrigerator or at room temperature in your pantry. Some foods are safe to eat with small amounts of mould growth, such as hard salami or cheese. However, if you find mould growing on your bread you should discard it. Since bread is a porous item, mould can be growing beneath the surface where you cannot see it. Ingesting mould can produce symptoms of allergic reactions such as wheezing or skin rash. Other adverse effects from mould ingestion include tremors and gastrointestinal distress. Ingesting mould can also be dangerous for pets. Dogs and cats that eat mouldy bread from the garbage can may develop tremors and symptoms of food poisoning.


Keeping the indoor humidity level around 40 per cent inside your home will help prevent mould growth. Examine your bread before purchase and never buy any bread item with visible mould growth. Avoid leaving any perishable items out of the refrigerator for longer than two hours and always keep food covered to avoid mould spores landing on the surface of the food.


If you find mould growing on your bread, throw it away. Do not stiff or smell the mould, as this can cause symptoms associated with allergic reactions. Always wrap your mouldy item in plastic or place in a sealed bag to avoid accidental ingestion by children or pets.

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About the Author

Tracy Hodge has been a professional writer since 2007. She currently writes content for various websites, specializing in health and fitness. Hodge also does ghostwriting projects for books, as well as poetry pieces. She has studied nutrition extensively, especially bodybuilding diets and nutritional supplements.