As I reported Sunday, the CDC has declared pork products safe to eat, as the H1N1 flu is an airborne (versus foodborne) illness.

The National Pork Board has been working overtime to reinforce this point, adding: “Modern pork production practices are designed to protect both animal and human health. Animals are housed in temperature-controlled facilities that are scientifically designed to ensure the health and safety of the herd. Modern pork production practices keep the animals clean, safe and protect the animals from predators, disease and extreme weather.”

While many farms—particularly organic ones—meet health and safety criteria, others continue to abuse their animals. The Center to Expose & Close Animal Factories (CECAF) has launched a new campaign to heighten awareness of these abuses, which were recently exposed in the HBO documentary Death on a Factory Farm (now available on DVD). According to CECAF, health hazards include manure dumping, manure spraying, emissions of toxic waste and illegal disposal of dead animals, among other transgressions.

Smithfield Foods, a U.S. company that operates a huge industrial pig farm in Mexico, is submitting samples from its swine herds to Mexican officials. As noted Sunday, townspeople have been complaining about farm runoff and were quick to point a finger when the H1N1/swine flu story broke. In a public statement, Smithfield executives said: “There is no evidence of the presence of North American influenza in any of the company’s swine herds or in its employees at any of its worldwide operations, including those in the United States.”

CECAF has called on Smithfield to release specific information on its Mexico farm and to open the facility to independent testing by international health officials.

Meanwhile, New Scientist reports “this type of virus emerged in the U.S. in 1998 and has since become endemic on hog farms across North America.” Granjas Carroll, the Smithfield subsidiary that last year produced 950,000 hogs in Perote, Mexico, would not provide reporter Debora MacKenzie with any specific swine-flu test data.

Investigations must continue to determine where the H1N1 strain originated.