Confession time. When presented with mouldy or slimy food, I spend some serious time in my head weighing up whether I should throw the food out (whereas others with higher food quality standards may toss the whole thing straight away). I have been known to ... push the boundaries ... of what may be considered safe from a food perspective.** This, coming from a girl who is terribly prone to food poisoning.
Bizarre! But I really struggle with food waste, which is part of my rationale for pushing those boundaries. Did you know that Australians toss out $5.2 billion (!!!) worth of food each year?! As a nation, we're throwing away more food than the amount we spend on digital equipment such as flat screen TVs. And I sure could use a flat screen TV!! I also feel developed-nation guilt for throwing food away, when I know people not far away (including in my own country) aren't eating well. So I sometimes persevere. Particularly when it comes to cheese and tomato paste - I just cut it off/scoop it out and hope for the best. And to be honest, so far I have NEVER poisoned myself. So it can't be all bad, right? Right??
So. Today's burning question - and source of useless but useful trivia (useful to food non-wasters such as myself, anyhow) - is: which foods are ok/safe to eat if they have been attacked by mould? The subtext to this question is: am I being as repulsive as my flatmates think I am when I lay into cheese that only moments before has had spots of black chopped off?
The answer is: some foods are ok, others are not. (Derrr).
Dr Ailsa Hocking of CSIRO Food & Nutritional Sciences says hard cheese is one of the few foods where what you see is what you get, at least from a mould perspective. Apparently the low moisture content of hard cheese and its dense structure means mould will usually survive only on the surface, rather than spreading invisibly into the cheese. So it should be safe to cut around the affected area and eat the rest of block. (Score! I am not disgusting!)
But many other foods, including mouldy bread, are better off thrown away. (It's ok, folks. I already don't eat mouldy bread) Not only might the mould be growing beyond the areas you can see, but if a food like yoghurt is old enough to have mould (yikes!), it might also contain harmful bacteria which could cause a bout of diarrhoea (hey... that's the poor girl's weight loss!).
"If you can see a mould growing, there can be other microbes in it as well. It's really not worth making yourself sick," Hocking says.
Authorities suggest that a good rule of thumb to judge whether a mouldy food can be saved is its moisture content. Foods with a high moisture content such as cooked casseroles, soft fruit and veg and soft cheeses can have mould growing below the surface – branches and roots they send down into the food – and you won't necessarily be able to see them.
The same rule goes for porous foods such as bread and cakes which have become mouldy. All of these foods should be binned if you spot mould on the surface.
Of course, certain domesticated moulds are deliberately introduced into our food as part of the production process - think blue cheese. While these are safe to eat, if a soft cheese that has been made with domesticated mould starts growing other types of mould, it should be discarded.
On to jams and - by extension - tomato paste. Hocking says if you are careful, you can try to scoop off the affected parts and it might be ok – but it can be hard to do this without spreading the mould around and back into the jam. This happens because all moulds produce spores. These can float in the air and once they settle, start a fresh crop of mould on your food.
As mould on our food is so hard to avoid, here are some general guidelines:
Discard all of these foods if mouldy:
• Luncheon meat, bacon, and hot dogs
• Yoghurt, sour cream and soft cheese
• Soft fruits and vegetables
• Bread and baked goods
• Peanut butter, nuts and legumes
These foods can be saved from mould:
•Hard salami – scrub mould from the surface.
•Hard cheese – cut off at least an inch around and below the mould. Don't let the knife touch the mould and recover the cheese with fresh wrap.
•Firm fruit and veg – small mould spots can be cut off.
**Note: For all those who I cook for, I do NOT give you slimy and/or mouldy food.