Is eating mould as bad as we think it is?
The first question is, what are moulds?
Moulds are microscopic fungi that spread very easily. They have roots and branches and the colourful part we see is usually only like the top part of the iceberg.
Some moulds can cause allergies as well as respiratory problems. Some can even produce poisonous mycotoxins. According to the Food and Agriculture Organisation, those toxins can affect around 25% of the food in the world. The most famous are aflatoxins that can even cause cancer.
How does mould spread in food?
The basic rule to remember is that moulds spread very easily in soft food but have much more difficulty with hard food.
Bread for example should be thrown away as soon as you spot a little bit of mould, because the roots probably already grew everywhere inside. The same applies to most dairy products such as yoghurt or cream, pasta or casseroles and most meat.
For cheese, fruits and vegetables it is a little bit more complicated than this. You need to find out first if those are soft or hard ones as it depend. Cabbage or carrots are hard, while tomatoes or peaches for example are soft. Throw the soft ones away if you think there might be mould. The same applies to cheese. Soft cheeses like brie or camembert and obviously cottage and cream cheese are more risky than cheddar or gorgonzola.
If hard food is not as risky as soft aliments, it does not mean you can eat the moulds on it! You need to cut off the mouldy part (and about 1 inch around it as well) and then make sure to keep it protected under plastic film.
What about cheeses that are made with moulds? Are they safe to eat?
Specific types of moulds are used to give taste to those cheese (Penicilium roqueforti and Penicilium glaucum) and those are perfectly safe. They cannot produce any kind of toxins in cheese. However, other kinds of moulds can still grow in cheese so try to stay careful.
The moulds that are use to make cheeses such as Blue, Roquefort, Stilton come from the same moulds that are used to make penicillin. If most people allergic to penicillin can eat those cheeses without an issue, some can have allergic reaction. Do tests with your allergist beforehand.