I wouldn't bet on that. Anthrax is actually very, very hard to kill. It can spore up for a long time waiting for the correct conditions. Treatment is possible, but the Reich can't do it, all they have are 1st Generation Sulfa drugs and they are ineffective.Yeah, I think that the whole white powder Anthrax circus has made people drastically overstate the deadliness of Anthrax. Anthrax was weaponised because it's spores can be safely and easily be warehoused for years in bombs and artillery shells, so it fit well into the military logistics chain, not because it's very deadly. Plus the original plan was to air-drop Linseed cakes to be eaten by cattle. Yeah the cattle will die, which will cause starvation in Germany ,but elementary public sanitation will prevent a human epidemic.
EDIT. Plus, I don't think it would take the Germans long to do some lab tests and figure out what's in the cakes that are being dropped by heavy bombers.
Anthrax infected animals that are slaughtered and consumed are also highly infectious. One of the most recent human outbreaks was in 2010 in the Philippines. 400 people were infected from one water buffalo carcass (don't know if it was some BBQ or what other group circumstances). Even with medical intervention two of them died (fortunately Cipro is literally cheap as dirt, otherwise the toll would have been higher).
Germany won't look like the 14th Century Black Death, but the death toll would be fairly impressive, even by WW II standards. It will also be poisoned as far as agricultural use for generations.