Many of us tend to follow the rules for Serv-Safe requirements for food safety. That means we try to avoid letting the meat or food of any kind sit in what is commonly considered to be the danger zone for bacterial growth. In a way, it is safer to rely on scientists who understand the risks of spoilage mechanisms.
That being said, most spoilage mechanisms we worry about are bacteria, and these little guys are remarkably resilient. While it is commonly considered safe to eat food at the temperatures we cook at, some spoilage bacteria are not killed at temperatures below boiling. That would be 212F. Even at that temperature, some bacteria can survive these temperatures for 15 to 20 minutes. If you think about it, your meat internal temperature will never achieve these temperatures, hopefully. So, if you allow the bacteria to start growing, and you have held the meat in a stage on your cooker or in storage that these bacteria have time to get into the meat, you have created a situation where you cannot kill them under even rather extreme cooking temperatures.