mouldy bread

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Matheous | 17:40 Wed 11th Oct 2006 | Science
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Is it safe to eat mouldy bread considering presumably that the mould is the basis of penicilin?


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Its just that I have in the past toasted some brown bread only to discover the rest of the loaf had some blue mould on!
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It's not advisable. I'll give you some general pointers and hopefully, answer the points made by EDDIE51

Some years ago when I first went to college, we always ended up with mouldy sliced bread in the cupboard at the various student flats. We used to throw the bread away until some bright spark had the idea of toasting the bread. I can't honestly say we suffered any ill effects. In hindsight, it was stupid. Here�s why.

The blue-green coloured fungi you see on mouldy bread are likely to be one or more species of Penicillium. It is true that one species called Penicillium notatum, from which Penicillin can be derived, may occur on bread, but the species is rarely present. Sometimes, a white rim may be seen around the infected area on the bread.

The problem is that Penicillium species hardly ever grow alone on bread. More often than not other fungi such as Aspergillus, Fusarium and others grow alongside the Penicillium. Although some Aspergillus species may be recognised by their black spores, other fungi may be whitish or transparent and almost invisible to the naked eye.

Almost all these fungi can produce poisons called mycotoxins if the conditions are right. This doesn�t happen all the time and the presence of mould does not mean that mycotoxins have to present - but it is a real risk, as mycotoxins are harmful to humans. The extent of the harm can vary from kidney disease to death depending on the amount ingested. While this is not very likely to occur following the ingestion of the odd slice of �furry bread�, the risk is there. Aspergillus species in particular produce a really nasty substance called aflatoxin, which has been known to cause hundreds of fatalities worldwide in recent centuries. Other moulds produce carcinogenic substances on occasions.


Wiping the mould off the bread is not the answer as the filamentous hyphae of the mould pervade the bread and are invisible to the naked eye. These hyphae may also contain the various mycotoxins. Toasting the bread only destroys the parts of the mould on the surface of the bread: the hyphae inside the bread may survive along with the mycotoxins they may contain.

In addition, mouldy bread will often succumb to bacterial infection with species such as Staphylococcus soon after mould establishes itself on the bread, because the bread becomes moister following mould growth. Ingestion of these bacteria will almost certainly result in food poisoning.

So, I would suggest that mouldy bread is best avoided.

EDDIE51 is correct in saying that "mouldy cheese" is eaten. Stilton and others do contain Penicillium species and people eat the horrible stuff day in and day out without any harm. The reason is simple. These cheeses and some other food products contain Penicillium roquefortii or Penicillium camembertii species, both of which are totally harmless to humans and they do not produce mycotoxins. That's the difference.
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Ok. No it's not!
Blimey prof ..... I shall look at a slice of mouldy bread in a whole new light , from now on .

Now then .... when did I open that packet of bread ... ? aah crumbs .. iv'e got to nip to the corner shop , in order to have some toast tommorow morning !!!!
Check out that use by date!
Thanks for the info guys.I accidently ate a piece this arvo and remembered that mum said that cheese was ok but not mouldy bread, so I did a 'google' and found you towards the top !
Question Author
theprof -Thanks 4 an excellent answer- if I knew how to give stars -I would do so....!

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