I have a bottle of Mustard at work that I use every once in a while… Does Mustard ever rot? How often should I get a new bottle?
Mustard is highly acidic (due to the vinegar used). That keeps it from spoiling.
I vote for checking the label.
If it is a container that is reusable, then introducing air and bacteria to it will affect it at some point.
Some foods are so salty and or acidic (vinegar) that they have longer shelf lives, but it doesn’t mean endless.
Mustard and Mayo packs apparently last forever, provided they are kept sealed from day one (so says the SDMB when I asked!) - I have a 10 year old mayo pack - never opened - but I ain’t eating it!
I ** Make** mustard and I vote for it eventually goes bad. yes, it’s highly acidic, but also some varieties (check lable) have ingredients in them (eggs for instance) that need refrigeration.
I’ve had some that went bad after being left out, unrefrigerated for over a year.