About a month ago, I froze some ground sirloin on the same day that it expired. Is it still safe?
It's gonna be a surprise. You have to eat it and find out.
Sell by date and expiration date are different things, and both are conservative guesses to avoid lawsuits.
Ground beef goes rancid as an early stage of "going bad" sniff it.
Your omnivore instincts will tell you if it is rancid or not.