does nam pla spoil?
re: JungMann's comment, it's not spoiled, it's fermented...big difference.
it is *possible* for fermented foods to spoil - they can become contaminated with mold or bacteria. the process of fermentation doesn't preserve food FOREVER, it just retards spoilage and greatly extends shelf-life. however, it's HIGHLY unlikely that a bottle of fish sauce is going to spoil when stored properly in the kitchen cabinet of a modern home...and there's no need to refrigerate it.
oh, and that expiration date means nothing. in fact, most foods that bear "use by" or "sell by" dates can be eaten safely well beyond the date. we had a discussion about this last week...
Yes, fermented foods can definitely spoil, but for the sake of argument, the salt content in this stuff is so high that I would imagine any living organism would find it hard to stay alive in there.
(But don't ask me how the fermentation took place in this case then -- thinking out loud, I realise I am contradicting myself here!)
I saw a show that showed how they make it. They clean the fish(dependent on what kind they are making), place in wooden barrels, fill with water, and put straw lid on it. Then they put outside in the elements to ferment for a long time, a year or so I believe. They then put the pour out and strain the solids from the liquid and bottle it.
I don't believe refrigeration is required here.