To quote a friend, "It is best to be comfortable when making any choices that relate to safety. Harder cheeses such as Monterey generally do not possess the characteristics (such as high moisture) that make pathogens happy. As a result, the risks are not high of pathogen survival. The aging time helps to reduce possibilities of pathogen survival, because starved of hospitable conditions, pathogenic microbes die. That said, it's up to you. People have been living well eating cheese that has had much worse hygiene practices. Without testing there's no 100% way to tell."
The thing is, yes, there are pathogenic bacteria everywhere, and yes, you technically can't tell when some of them are there by looking at them. However, the age, acidity, and salt combined make it a hostile environment for said bacteria.
I'd eat it, for what it's worth.