Well, the last time I sat in Bio 2
class Richard Nixon was president and my hair was a little longer...so don't quote me either!
Moisture content (
water activity) has a lot to do with the ability of the botulinum spores to grow. Check page 6
CDC on Botulism
Temperature, pH, competition from other microorganisms, moisture, and oxygen. Salt brining, either dry or wet, will reduce the internal moisture, think speck or prosciutto, but these products are air dried for months. Then give it a smoke, which
should reduce the moisture level even more. No moisture, no botulism (& fingers crossed).
It's unfortunate that nitrites are presumably bad for us because they're really effective at preventing botulism spores from growing and from the spores producing toxin (note the differences in an additional 100 micrograms/gram of nitrite levels).
Effects of nitrites on botulism