Mould – what’s the big deal? Mould can be responsible for whole families suffering from sinusitis, and other allergic symptoms, even unexplained and repeated flu. Moulds can play havoc with health as they produce compounds called mycotoxins, which if consumed over enough time, can cause serious illness, including liver cancer. “A lot of these compounds are carcinogenic,” says Dr Ailsa Hocking, of CSIRO Food and Nutritional Sciences. “Mould resides in most places and we really do need to know if we need to avoid it in our food and homes to stay healthy”.

There are many different types of moulds that grow on our food that can make us ill. The most common include Aspergillus and PenicilliumBotrytis is the fur you see on strawberries. Moulds are tough survivors; they can grow in the fridge and survive freezing, making them difficult to avoid.

Mouldy bread is better thrown away, because the mould would be growing beyond the areas you can see. “If you can see mould growing, there can be other microbes in it as well.” Hocking says. “If yoghurt is old enough to have mould, it could cause a bout of diarrhoea,” she says. You can keep the cheese after cutting off the mould though; the low moisture content and its hardness means the mould is only on the surface.

The key to judging whether to throw out food that you see with mould is the moisture content of the food. Foods like cooked casseroles, soft fruit and vegetables and soft cheeses can have mould growing below the surface, because moulds send branches and roots down into the food that you just can’t see. For this reason, all cooked food should be refrigerated two hours after serving. Porous foods like bread and cakes that you can see mould on should be discarded, as invisible moulds will have penetrated them. Some domesticated moulds as found in blue cheeses are safe, but if a soft cheese starts growing other types of mould, it should be discarded. You can tell by its different colour.

What about jam? The US Food Safety and Inspection Service says moulds on jam could be producing mycotoxins and the whole lot should be discarded.

Guidelines from the US Food Safety and Inspection Service are:

Discard the following if found with mould: 

Luncheon meat, bacon, hot dogs, yoghurt, sour cream, soft cheese, soft fruits and vegetables, bread, baked goods, peanut butter, nuts and legumes, jams and jellies.

Foods that you can rescue from mould are:

Hard salami – scrub mould from the surface.

Hard cheese – cut off at least an inch around and below the mould and use fresh wrapping. Firm fruit and veg – small mould spots can be cut off.

Airborne moulds

If you notice that your sinus and allergy symptoms disappear when you leave your home for a few days, and return when you come back, there is a good chance you have pinpointed the cause of your allergies.

Moulds grow on wallpaper, carpet, under the floorboards in heating and air-conditioning systems and produce spores, which become airborne after drying out or if disturbed.

About 20 per cent of the population is allergic to mould spores. Apart from being allergenic, some also contain the toxic mycotoxins. Mould spores can cause allergy, headache, fatigue, running nose, sneezing, coughing, pneumonia and asthma. 

Keeping houses and offices dry eliminates or slows the growth of most mould species. The best way to control mould growth is to fix leaks, attend to condensation, and increase ventilation. Dry any water leaks within 48 hours. The earlier the mould is discovered the cheaper and easier it is to get rid of the problem.

Not all moulds are dangerous to health, and not everyone’s health is affected by airborne moulds, but mould should be removed as soon as it is noticed. A simple way to reduce mould growth is to wipe surfaces, including the bathroom, with vinegar to prevent regrowth.