Monique Y. Mudama wrote:

About a week ago we added sauteed green onions and mushrooms, as well
as grilled bell peppers and zucchini, to spaghetti sauce (the kind in
a plastic jar).

I was thinking that with no meat, it would still be good, but someone
told me that mushrooms go bad in 2-3 days.

Thoughts? Do I need to toss all that sauce?

Under REFRIGERATION???? (And COOKED?) Unless there's
something radically wrong with your refrigerator, cooked
foods are good for at least a week or two in the 'fridge.
.....Heck, I've kept RAW mushrooms that long! (They get a bit
too discouraged looking to use in salad by then, but they're
perfectly fine if you cook them.) People living in
temperate climates used to keep cooked food for several days
in their "larders" WITHOUT refrigeration. Nowadays everyone
seems to think even things like honey and olive oil (which
kept for hundreds of years in Egyptian tombs) not only
require refrigeration, but will spoil within a few days,
even so. Get REAL, people!