I've been experimenting cooking bacon on the George Foreman grill. I'm trying it out a little less cooked and was wondering, how do I know if it's cooked enough to be safe to eat? Recently I've tried coating the bacon in maple syrup and it really makes it difficult to see when the bacon starts to brown.
Bacon cooks to safe very quickly. Once it's opaque it is safe to eat.
Raw bacon is itself pretty low risk, provided it has been properly cured. Even if it wasn't cooked through, you are unlikely to come to harm.
The Maillard reaction happens around 140°C/284°F, which is much higher than any bacteria, which can be found under reasonable circumstances, will survive. (There are some deep ocean bacteria that might survive, but no idea how they would get onto your bacon.)
The bacon I assume is a thin slice of bacon. These are usually around 1/32 inch thick. A 1-inch steak well-done (76°C/169°F) takes 8-10 minutes. Your thin slice of bacon will have a safe temperature after a minute for sure therefore and this will be way before it gets brown.
The benefit of the George Foreman grill is that it's a stable temperature every time, unlike a coal grill. Just measure the time for your bacon without maple syrup - you will need the same time with maple syrup. The bacon is too thin to store much heat and so there is not much thermal energy lost.