Is Mould on Food Dangerous?

If you cut mould off your bread, you may be putting your health at risk

Exposure to mould on food can leave you susceptible to allergic reactions, respiratory problems and even more serious illness

You’re in a rush for breakfast and your last piece of bread has a spot of mould on it. If you’re like a lot of folks, you might consider removing the mouldy spot and eating the bread anyway, but you need to know that moulds can be a hazard to your health.


Moulds are microscopic fungi that live on plant or animal matter. They grow from tiny spores that are transported by air, water or insects, and their growth is encouraged by warm or humid conditions. When these spores end up on a piece of damp food, they grow into moulds that produce chemicals that break down the food and make it rot. 



The Three Components of Mould

Moulds typically consist of three parts:


• Root threads that invade the food they live on;

• A stalk that rises above the food;

• Spores that grow at the end of the stalk.


Under the right conditions, some moulds produce poisonous substances (mycotoxins) that can trigger allergic reactions, respiratory problems and even more serious illness. The only part of the mould you see is on the surface of the food. However, where there is heavy mould growth, root threads have usually invaded deeper and toxins may have spread throughout the food.



How to Avoid Mould Contamination of Food

• Always cover food when you want it to stay moist.

• Empty open tins of perishable food into clean containers.

• Put perishables in the refrigerator as soon as possible, and use leftovers within two to three days. 

• Clean the inside of your refrigerator at least once a month.

• Check best-before dates and examine food carefully before you buy it.



What to Do If You Find Food with Mould on It

• Avoid sniffing the food as the mould could cause respiratory trouble.

• If the food is covered with mould, wrap it thoroughly to prevent mould spores from spreading to other foods and discard it.

• Clean the area where the food was stored and check other foods around it.


It’s been suggested that firm fruits and vegetables and hard cheeses with a small mould spot can be eaten if you cut away an area one-inch (2.5-cm) around and deep. However, no matter how small the visible spot, mould can penetrate deep into foods, so the very best advice remains “if in doubt, throw it out.”

Originally published in Wellness Matters, Canada Wide Media’s quarterly newsletter on health and wellness.