The letter has been sent by Congresswoman Louise Slaughter, who is a microbiologist and she has also asked the restaurants to provide a breakdown of the percentages of beef, pork and poultry which they serve raised "without any antibiotics," raised with antibiotics only for "therapeutic reasons," or raised with "routine use of antibiotics."

"Very simply, consumers have a right to know what's in their food," said Ms Slaughter.

"It's like that old commercial, 'where's the beef?' We just want to know, 'what's in the beef?' The US is facing a growing public health crisis in the form of antibiotic-resistant bacteria, and information about how these companies are contributing to its rise or resolution should be available to consumers."

Citing some alarming statistics, including that in 2011 the US had the most outbreaks ever of antibiotic-resistant Salmonella due to contaminated meat and poultry, the letter noted that "the practice of routinely feeding antibiotics to chickens, cows, and swine has been shown to harm human health by contributing to diseases that do not respond to treatment."

"There are some who would have us believe that we must pump our food up with antibiotics to keep prices low and affordable," she said.

"But the food industry has proven success stories and leaders who understand the benefits that come from raising and serving antibiotic-free meat. It is not incompatible for us to have healthy and affordable food."

In 2010, the Food and Drug Administration released data revealing that in the United States 80 percent of all antibiotics are used in food-animals, not humans. Since then, and in conjunction with a rise of antibiotic-resistant bacteria, the practice of routinely feeding antibiotics has come under scrutiny.

In December 2011, Congresswoman Slaughter hosted a briefing titled "Keeping Antibiotics Working" where farmers and successful businesses extolled the benefits of tapping into the growing domestic and international demand for antibiotic-free meat.

The group urged congressional action to preserve antibiotics for the treatment of human diseases, an issue Slaughter has been working on for years.

Since 2007, Congresswoman Slaughter has been the author of legislation titled The Preservation of Antibiotics for Medical Treatment Act (PAMTA), designed to ensure that we preserve the effectiveness of antibiotics for the treatment of human disease. The legislation would prevent agricultural overuse of seven classes of antibiotics important for human health.