Taiwan's Legislative Yuan passed Tuesday a controversial amendment to a food safety law, banning imports of certain beef products from the United States, about two months after the government lifted the ban. Ruling and opposition party legislators passed the amendment to the Act Governing Food Sanitation, which bans beef imports from countries with documented mad cow disease cases over the past decade. The amendment came in the wake of two months of contention since Taiwan and the United States signed a protocol in October to allow the entry of bone-in beef and other beef products, including ground beef and offal, that had previously been banned out of concern over bovine spongiform encephalopathy (BSE), or mad cow disease. The administration of President Ma Ying-jeou had been widely criticized for lifting the ban imposed in 2005. It was not immediately clear how the legislature's decision might affect relations between the United States and Taiwan. The American Institute in Taiwan (AIT) -- which represents U.S. interests in Taiwan, on Tuesday issued a statement expressing 'deep regret' over the move. 'The United States deeply regrets the Legislative Yuan's decision to restrict U.S. beef imports and the legislature's decision to abrogate the bilateral protocol being negotiated in good faith,' said AIT spokesman Christopher Kavanagh. 'This action also undermines Taiwan's credibility as a responsible trading partner and will make it more difficult for us to conclude future agreements to expand and strengthen bilateral trade and economic ties going forward,' Kavanagh added. The amendment will effectively bar U.S. ground beef, beef offal and other beef parts such as the skull, eyes and intestines from access to Taiwan's market. Calling the amendment a 'victory of the people, ' DPP Legislator Lai Ching-te said President Ma should apologize to the people for the dispute triggered by the beef imports and that National Security Council Secretary-General Su Chi, who led the last beef trade talks with the United States, should resign from his position. Lu Hsueh-chang, a whip of the ruling Kuomintang's legislative caucus, said the legislative process fully demonstrates that Taiwan's democratic system is becoming increasingly mature. U.S. officials have repeatedly said tests have shown its beef products are safe. Coming under criticism for lifting the ban, Taiwan's government has promised measures to inspect the beef products and ensure they are safe before they are allowed to enter Taiwan's market. But the lawmakers were intent on overturning the administration's decision. Tsai Huang-liang, another DPP legislator, said the passage of the amendment was in compliance with public opinion and symbolized a vote of no confidence in the Ma administration. The legislature on Tuesday simultaneously passed three riders, including one in which the legislature pledged to cooperate with the executive branch in coping with international pressure. The second rider called for the government to tighten its inspection of beef imports to make sure they are from cattle younger than 30 months, and the last one stated that if there is outcome from a proposed referendum on the beef issue, the government should comply with it. The legislature's decision, however, is not expected to affect an upcoming U.S. decision on arms sales to Taiwan. Experts have said Washington has historically not linked security issues with trade issues and the U.S. government is bound by law to provide Taiwan with the means to defend itself. 