- Over the last 7 years, the US had a few cows with Mad Cow Disease (three out of hundreds of millions)
- The Korean and Japanese governments banned US beef because of a concern for public safety.
- A respected Korean TV show had a program which was highly critical of US Beef and pointed to many dangers of eating it. Later they admitted that it was full of inaccuracies and mistranslations.
- The people became outraged when the government allowed US beef to come to market again. Many thought the government was ignoring their concerns and was only worried about having a good relationship with the US.
The problem has been there are some legitimate concerns (there were a few cows sick) that got totally blow out of proportion by the TV show. Many people believe that there is a huge number of sick cows, that US sends beef to Korea which they would not eat themselves, and that Koreans are particularly susceptible to the humane variant of mad cow disease. From the research I have done (see wikipedia or the US embassy site for good info) this information is not true.
The bottom line to me is a safe product (nobody has ever gotten the human variant of Mad Cow disease from American Beef) has been decimated. Mothers have unnecessarily worried that they had fed unsafe food to their children. The US is seen in a bad light.