When swine flu first appeared, some people attempted to blame Smithfield, a huge and modern pork producer for creating the disease. Here's a video showing a modern finishing barn*. Presumably, Smithfield raises their pigs in this sort of a barn.
Tests now show that there's no H1N1 virus at Smithfield's farm in Mexico.
In general, diseases like the current one are more likely to come from small farms where people, pigs, birds, rodents and dogs live in close contact. Smithfield's farms are as far from that as technologically possible. Here's an example of what you do when you are serious about avoiding disease - run all the air your animals breathe through a virus-proof filter.
* The video is interesting. Among other things, the farmer explains why keeping pigs in large groups helps, because it prevents the formation of a pecking order and the resulting poor doers and dead pigs.