Washington ( CNN ) -- The Food and Drug Administration on Friday said it was studying a federal judge 's order that it consider withdrawing two popular antibiotics from use in livestock . In a ruling issued Thursday , U.S. Magistrate Judge Theodore Katz said that the FDA must issue notices to drug manufacturers that the drugs will be withdrawn unless the companies can prove they 're safe . Katz did n't issue a full ban -- suggesting the manufacturers should be given a hearing to make their case . The suit was originally brought by the Natural Resources Defense Council , which argued that the FDA has allowed livestock producers to use popular antibiotics penicillin and tetracycline in feed for more than 30 years for purposes other than treatment of illnesses . The NRDC claims `` the indiscriminate use of antibiotics in animal feed can lead to the growth and spread of drug-resistant bacteria capable of infecting people . '' Antibiotic resistant bacteria are fast-moving , can be deadly , and can infect otherwise healthy individuals . In its statement , the FDA said , `` We are studying the opinion and considering appropriate next steps . '' Thursday 's ruling can be traced back to decisions the FDA made more than 30 years ago . In 1977 , the FDA announced plans to withdraw approval of some antibiotics used in livestock feed . The drugs have been used by livestock producers to help promote growth and feed efficiency . At the time , the FDA found the practice of using antibiotics for non-medical reasons unsafe . Drug manufacturers requested hearings , but the FDA never scheduled meetings and nothing else was done . The approval remained in place . In subsequent years , new medical evidence suggested that treating livestock with antibiotics increased risks to human health . But according to the judge 's ruling , the FDA never changed its position . In May , two petitions circulated urging the FDA to finish what it started in 1977 . When the FDA did n't respond , the NRDC filed suit . In December , the FDA withdrew the original 1977 notices saying they were outdated . The suit alleged that the FDA 's failure to withdraw approval of penicillin and tetracycline after the 1977 research was unlawful and violated the administrative procedure act . According to the NRDC , 80 % of antibiotics used in the United States is used in livestock . The group also says 29.8 million pounds of antibiotics were used in livestock in 2009 , up dramatically from the previous decade . Meanwhile , the ruling is n't sitting well with beef producers . The National Cattlemen 's Beef Association noted its dissent in a statement saying its members were `` disappointed with the decision , '' and that practices include the `` judicious use of antibiotics to prevent , control and treat any cattle health issues . '' If drug manufacturers fail to show that using the antibiotics in livestock is safe , the FDA commissioner must issue a withdrawal order . But the judge noted that if the drugs are deemed safe , the FDA can not withdraw them from use .
The FDA says it will study the matter . Beef producers are disappointed , say use of drugs is ` ` judicious '' and livestock with antibiotics may pose risks to human health .