With the current treatment of using antibiotics and other disease controlling substances, new strains of antibiotic resistant bacteria and resistant viruses have evolved, thus requiring more powerful drugs to maintain and control. Drug-resistant diseases are attributed to these more powerful, virulent viruses and antibiotic resistant bacteria. We must find better ways of controlling and sanitizing our food.
According to a recent study in EMBO Molecular Medicine by Mark Holmes of Cambridge University, there were at least two cases of MRSA transferred from livestock to humans as confirmed by a DNA sequencing of the pathological agent. These cases occurred in Denmark which has such a low occurrence of MRSA that any case is a notable outbreak.
The large amount of bacterial antibiotics in meat, while eliminating bacterial organisms, fuels the evolution and change of our biological defense mechanisms. The more that companies use antibiotics, the more bacteria will become immune and fight against it. It is a constant game of catch up that inevitably leads to more resistant strains of bacteria.
While I am the first to argue that the meat industry in the USA is one of the best, I think that what they are doing is feeding into the problem of diseases becoming resistant to drugs. They feed cows and what not with a lot of drugs, and it is a problem.