[Jersey Kid]

I seriously doubt that Carbon dating would distinguish between fresh and 3 year old antrax... It's not that accurate when we talk about such a short periods of time...

In my opinion it can be done much easily by by C13 NMR, same general technique as for determening for example, if caffeine came from coffee, tea or was synthesyzed in the lab...

[Jersey Kid]

As for ways to kill it, tons,
depending where you want to kill it...
Radiation (either Microwave, Gamma-Cobals 60 or E-beam), Plasma (either Hydrogen peroxide or paracetic acid),
Liquid chemicals wash (for example chlorox, formaldehyde,propylene oxide, hydrogen peroxide, acetone, toluene)
Gases of vapors (for example Ozone, Ethylene oxide gas, Hydrogen peroxide vapor).
Also UV from sun or from UV lamps

[Paleo Conservative]

I seriously doubt that Carbon dating would distinguish between fresh and 3 year old antrax... It's not that accurate when we talk about such a short periods of time...

That's what I thought. From geolomorphology papers I read where carbon 14 dating was used, the labs results could date materials to a century or half century.