Chris,
That's what they say--it's convenient--but it is not accurate. Though total time is a concern, potential for bacterial growth depends on likelihood of which bacteria might be present, whether one is dealing with raw food, food in the process of being cooked, or already cooked food, the specific food in question, and the actual unsafe temps involved. E.g., a bowl of pulled pork served hot at a summer picnic but allowed to cool on the table--well, you're looking at more like 2 hours max as you have three major issues at play: it was already cooked, it was handled, as the pork cooled on its own on the summer day it would end up hanging in the far more dangerous zone of 85-105.
Conversely, a package of steaks left out on the counter to thaw would be safe to cook and consume 6 hours later. Though the surface temp of the steaks would warm first they would stay cold enough, though above 41, not to cause concern (pathogenic bacterial growth is low below 55 on uncooked foods); the bacterial issues with raw meats meant to be cooked are different from those already cooked (spoilage bacteria compete and prevent growth of many pathogenic bacteria); the steaks are going to be cooked and thus pasteurized (bacteria are not a concern within intact cuts), etc. It's not cut-and-dried, as you see.
The 'danger zone' top end is not 140, it is 130. 140 is a political number. If your therms are accurate feel free to use 130. This has been a known quantity for some time--FSIS started pushing to change the number in the late 1970s--but lobbying from several states caused the FDA to cave. Instead, they compromised at 135 and it's 135 that's codified (it's in the FDA's Food Code). (No one trusts consumers to know what they are doing but rather than actually instructing the public on the importance of using accurate tip-sensitive thermometers...) Use whatever number above 130 you prefer but I think it is worth knowing the accurate number.
Mike,
Happy it went well. Good show.
