I cooked a pot roast in a crockpot yesterday and it cooked all day. We ate some of it for dinner, but some of our family was out late last night and so we left the roast cooking in the crockpot for them to eat when they got home. When I got up this morning the crockpot had been turned off and the roast/drippings were still inside. Is the roast "contaminated" with bacteria now? Or will it be okay if I heat it to boiling? Thanks!