Best if used by dates

I forgot to mention that refrigerating things like Worchester sauce will prolong their useful lives considerably. The cold slows down the loss of flavor, nutrients and oxidization. Won't do anything for baking powder though...

While I certainly would continue using either, I wouldn't panic. Your family was fine before you realized and they'll stay that way. Plus, don't forget, mushrooms are nothing more than fancy fungus spores and mold is a fungus too lol.

Killing? No. But those two products are far past their prime. Baking powder loses effectiveness over time. Worcestershire sauce is basically pickled fish. Twenty year-old fish doesn't sound too appetizing plus the oils will have oxidized which is a long-term health concern.

For the baking powder, test a spoonful in a glass of water. If it still fizzes vibrantly, then it's still good. The Worcestershire sauce should be trashed since it's been ~20yrs.

The baking powder won't be effective so I wouldn't use it. If the Worcestetshire sauce has been opened but you don't know when, I wouldn't use it