I honestly think that any container that was reasonably clean and washed like in a dishwasher is safe. Dry yeast is tough stuff too so I wouldn't worry about it. Should you have sanitized it? Of course but why worry now.
I have always wanted to conduct and experiment with two identical batches at the same time, just washing everything like you would a dinner plate with one and going through the usual sanitation process with the other. That fear of dumping 5 gallons of brew keeps me from trying it.