Earlier quoted context omitted.
I'm curious. Do you mean spoiled during the production process (ie was inedible to begin with) or spoiled in storage (ie was edible at time of purchase)?
Since fermentation is involved, I don't think there's a clear line between the two.
Fermentation is traditionally a process for preserving things. Provided it's carried out correctly the result will often be shelf stable for quite some time. Another important aspect is that if something does contaminate it there will usually be obvious evidence.
I was curious if this was an inherently dangerous dish or if locally a lack of effective regulation of industry was to blame. It sounds like it really is unsafe to at least some extent.