Can a roast that was fully cooked but left out too long be reheated enough to safe eat?

No, a roast that was fully cooked but left out too long cannot be reheated enough to be safe to eat. When food is left out at room temperature for too long, bacteria can grow rapidly and multiply to dangerous levels. Even if the roast is reheated to a high temperature, this may not be enough to kill all of the bacteria that have grown on it. Consuming food that has been contaminated with bacteria can lead to foodborne illness, which can cause symptoms such as vomiting, diarrhea, abdominal pain, and fever.

Therefore, it is important to follow food safety guidelines and refrigerate perishable foods promptly after cooking. If food has been left out at room temperature for more than two hours, it is generally not safe to consume and should be discarded.