Any foreigner who was in South Korea in 2008 can remember the furious reaction Koreans had when President Lee Myeong Bak announced South Korea would resume imports of American beef. There were protests--violent ones, even. I had just arrived in Korea at the time, so I was completely bewildered by what was going on around me. Between the dislike/fear of American beef and the general sentiment towards President Bush, I couldn't safely claim I was an American for fear of being ridiculed or yelled at by angry Koreans. I tried my best to explain that one cow or one person did not speak for the entire country, but those words fell on deaf ears, it seemed.
However, Korea itself is not immune to fears within its borders. From the middle of last year, the fear has been focused on H1N1 (originally thought to be a foreigners' disease) and measures have been taken to try and control the spread of flu. Many events were canceled because the organizers didn't want large groups of people to congregate and possibly spread their germs. For now, though, it seems that most of the initial fervor has died down, but the posters and advertisements reminding people to practice good hygiene remain.
Just this past week, an outbreak of hoof-and-mouth disease has stricken cows and pigs on various farms in Korea. As a result, 300 animals have already been culled from the herds for testing positive for HMD. and upward to 2,000 more animals will be culled in the next week or so. It's a major blow for Korea, who had been HMD-free since 2000, and it could affect their exports of pork to other countries. HMD can infect humans, but it is very rare. You can read more about HMD here, and the full story here.