[imgbelt img=pigs.jpeg]Federal officials are telling consumers it is perfectly safe to eat pork, but fears of a “swin flu” epidemic have collapsed stock prices of ag firms on Wall Street and have led China and Russia to ban the importation of pork from some U.S. states. So far, no flu cases have been discovered in major hog-producing states (Iowa, Illinois or Minnesoata), so these areas aren’t yet on the banned list. But commodity traders worry about what will happen with the first cases in those states arise.Smithfield Foods and Tyson Foods — both members of the Yonder 40 stock index — suffered large losses by mid-afternoon. Tyson’s stock was down by just over 10% Monday. Smithfield, the nation’s largest hog farmer, was off by nearly 12%.Robert Moskow, an analyst at Credit Suisse, issued a report early Monday warning that the “part that looks scariest for the U.S. pork industry is that Mexico accounts for 14% of U.S. exports and was off to a great start in 2009.” Exports to Mexico are expected to decline as people in that country refrain from going out as the epidemic grows. Smithfield, meanwhile, issued a press release today saying there was no evidence that the flu had infected its Mexican operations.