Rep. Louise SlaughterDorothy (Louise) Louise SlaughterLawmakers remember Slaughter in Capitol ceremony McGovern tapped to replace Slaughter as top Dem on Rules panel House majority rules spark minority fights MORE (D-N.Y.) on Monday urged McDonald's to primarily source the beef used in its hamburgers from cows raised without antibiotics.

In a letter to McDonald's director of sustainability Michele Banik-Rake, Slaughter praised the company's decision to buy hamburger beef from sustainably raised cows starting in 2016, but said the initiative could go further.

"Beef production is not sustainable if antibiotics are overused," Slaughter wrote.

Slaughter also suggested applying the same standard to McDonald's purchases of poultry for its chicken offerings.

"McDonald’s owns all of the chickens raised for use in your restaurants. With such leverage, you have a real opportunity to lead in sustainable poultry production as well," Slaughter said.

The New York Democrat said that McDonald's, which operates in 119 countries, had potential to revolutionize the fast-food industry standard for sustainable meat consumption.

"By primarily sourcing beef from cows raised without antibiotics, and by insisting on antibiotic-free poultry production, McDonald’s can jump-start a worldwide system of sustainable production," Slaughter wrote. "Animals raised under hygienic and uncrowded conditions will be healthier, reducing their need for antibiotics and increasing animal welfare."

Slaughter, the only microbiologist in Congress, is the sponsor of a bill, H.R. 1150, that would limit the use of antibiotics in agriculture.