 In 2001 , the FSIS approved the gaseous disinfection system as an intermediate step before the roller press freezer , and approved the disinfected product for human consumption , as an additive . The FSIS agreed with BPI 's suggestion that ammonia was a " processing agent " which did not need to be listed on labels as an ingredient . FSIS microbiologists Carl Custer and Gerald Zirnstein stated that they argued against the product 's approval for human consumption , saying that it was not " meat " but actually " salvage " , and that the USDA should seek independent verification of its safety , but they were overruled . In 2003 , BPI commissioned a study of the effectiveness and safety of the disinfection process ; the Iowa State University researchers found no safety concern in the product or in ground beef containing it . 
