I can't imagine how it would go bad, it's so salty. Like soy sauce or Worcestershire sauce.
I think it might be because it is seafood-based.
It's kind of like Better than Bouillon. It's such a concentrated, salty substance that I can't see how any pathogen could survive, much less reproduce, in it. All food pathogens require moisture to reproduce and salt absorbs water.I think it might be because it is seafood-based.
I just looked at the bottle I bought a couple months ago. The expiration date is in April 2023.Shelf life of oyster sauce is 18 to 24 months after purchase, 3 to 6 months after opening.