The rules were created in response to the nation's first case of mad cow disease in December 2003.
They require that brains, spinal cords and other nerve parts — which can carry mad cow disease — be removed when older cows are slaughtered. The at-risk tissues are removed from cows older than 30 months because infection levels are believed to rise with age.
The Agriculture Department said Monday it had cited beef slaughterhouses or processing plants 1,036 times for failing to comply with rules on removing those tissues, which are commonly called specified risk materials or SRMs. The violations occurred over 17 months, ending in May.
The number of violations amounts to less than 1 percent of all citations at those plants, said USDA spokeswoman Lisa Wallenda Picard.
"At no point in time did SRMs get to consumers," Picard said. "There was not one example of that."
The department released the information in response to requests made by several groups under the federal Freedom of Information Act. The records were from January 2004, when the rules went into effect, through May of this year.
One of the groups, Public Citizen, said the records showed serious problems in enforcing the rules. For example, there were mistakes in identifying animals' ages, which affected whether at-risk tissues were removed.
"Time and time again, they've said we have an SRM ban that is the ultimate public health measure they can take," said Patty Lovera, deputy director of Public Citizen's food program. "There are problems at a couple of levels in that whole policy that they keep bragging about."
Removal of nerve tissues is important but doesn't guarantee the safety of the food supply, said Jean Halloran, director of food policy initiatives at Consumers Union.
"We've always had a dispute with the bright line USDA seems to draw between dangerous parts of the animal and safe parts of the animal," Halloran said. "There's a lot we don't know. There's nothing absolute about 30 months. It's not a magic number."
A meatpacking industry official said the violations were minuscule and should not be worrisome.
"The truth is that these very low numbers ... demonstrate a remarkable level of compliance with federal regulations exceeding 99.9 percent," said Jim Hodges, president of the meatpacking industry's American Meat Institute Foundation.
Hodges compared the public risk to the likelihood of being struck by lightning and winning the lottery on the same day.
The United States has confirmed two cases of mad cow disease. The first, in 2003, was in a Canadian-born cow in Washington state. The second, a Texas-born cow, tested positive in June.
Mad cow disease is medically known as bovine spongiform encephalopathy, or BSE. In humans, consuming meat products tainted with BSE is linked to a fatal disorder called variant Creutzfeldt-Jakob disease. The disease has killed about 150 people, most of them in Britain, where there was an outbreak in the 1980s and 1990s.
One human case has been reported in the United States, but the person was living in the United Kingdom during the outbreak there.
By Libby Quaid