I'm not a botulism expert. What I know comes from food preservation by pressure canning. Also, there have been other threads on this forum that discuss botulism. Here is my meager knowledge:
1. Botulism is the oft-fatal paralytic illness that comes from consuming botulin toxin.
2. Botulin toxin is the by-product of anaerobic
proliferation of the bacteria clostridium botulinum.
3. In pressure canning (for non-acid foods), the temperature of the food needs to be raised for a sufficiently long time to kill the clostridium botulinum and
the opened canned food must be boiled in an open pot for at least 15 minutes in case botulin toxin is present. So,
...if there is botulism present is there anything you can do...
means you can use the open-pot boiling method at your own risk
. (My attorney made me say that.)
There are other anaerobic bacteria that form toxins, so the advice to let air circulate around raw meat does not only apply to prevention of botulism.
...if you put raw meat in a bag and evacuate the air as you do with these vacuum baggers you run the risk of botulism? How long would it keep before that risk arose?
I'd say that vacuum-bagged meat is supposed to be frozen, or at least refrigerated for a short period of time. I don't know what kind of time-frame we're talking about here.