Why does my vegetable soup taste sour after molding?

[Irish Guy]

Thank you for the welcome. I was looking for an answer for a cooking problem and found an answer that did not quite fit.
I made a huge amount of vegetable soup, kept boiling it some of it stuck to the bottom changed pots left it for two days, some mould formed on the top sides removed the mould blended the vegetables and after tasting it tastes a bit sour. Any idea why and what can I do to rescue the big pot of soup.

 

[Evo]

I don't know what you are used to eating, but it sounds like the soup has gone bad, no telling what kind of nasty bacteria could have grown, not to mention the mould that is in there. I would not eat it. Throw it out.

 

[rootone]

A sour taste is usually associated with acidity.
The bacteria and moulds Evo mentioned often excrete organic acids as a food breakdown product.
While eating 'gone off' food isn't usually lethal, it's definitely not healthy, could easily produce indigestion or worse, such as diarrhea.

 

[NTL2009]

Coincidentally, we went to a Polish restaurant over the weekend with friends, and while researching the place, I came across recipes for a sour soup. The process is similar to the process for souring some beers, like Berliner Weisse. Some grain is left in water to sour for several days. Grain is full of lactobacillus, which produces lactic acid, which protects it from other bacteria and mold that might be bad for us.

http://www.lthforum.com/bb/viewtopic.php?p=221326

But since you did not use a controlled, documented process, I'd toss it. Lactic acid = nice bright and tangy, mold could be bad.