Ike: That's the limit for Interstates, but some states allow higher weights on state highways. Kentucky allows coal trucks to exceed 100,000 in some places.
I agree that 70,000 pounds of bacon sounds a little high, and I'm not sure the truck would carry that much, in normal consumer packaging. On the other hand, if it was packed in, it could easily exceed that. A cubic foot of water weighs 62.5 pounds, a truck trailer is roughly 4000 cubic feet, so that would equal 250,000 pounds. Pigs float, barely, so bacon should be about as dense as water.