why is there dates on things like jam, margarine, ketchup, salad dressing (mainly i'm speaking of those without dairy products in them...like a vinagrette), peanut butter, etc., etc,. etc. even if these items sat in the fridge/cabinet for years you could probably give them a little stir and they would still taste the same.
i dunno....i don't go by the dates...i go by "if it looks bad or smells bad....it's bad. everything else is consumable" i've been using this all my life and haven't once gotten sick. to each his own i guess......