A coalition of consumer groups including the Pew Charitable Trusts this week submitted a letter calling for antibiotic use in livestock to be considered by a group crafting a definition of "sustainable beef."

Releasing a draft of proposed guidelines in March, the Global Roundtable for Sustainable Beef solicited public comment on the language until May 16. Missing in the draft, says the consumer group coalition, was any mention of antibiotic use.

In a written response to Ruaraidh Petre, GRSB executive director, the coalition explained concerns surrounding antibiotic use in animals.

Coalition, Congresswoman address proposed beef sustainability definition, say efforts should extend into antibiotic use

"The degree to which antibiotics are used non-therapeutically to raise cattle today is unsustainable, and the Roundtable’s criteria will be insufficient if they do not address these injudicious practices," the letter said.

"People and animals alike suffer when antibiotics stop working and every stakeholder in medicine and business shares the responsibility for curbing overuse and preserving the effectiveness of these life-saving drugs for as long as possible."

The definition is expected to become the standard for McDonald's, which turned to the Roundtable earlier this year for help in better defining its commitment to using only "verified sustainable beef" by 2016.

Related: McDonald's and Walmart Shot-callers Say Sustainable Beef Or Else

The group urged the Roundtable to consider including language that would set criteria for curbing the use of antibiotics for growth promotion and affirm requirements for veterinary oversight of antibiotic use on livestock.

The requests are similar to those FDA published late last year, which both require drugmakers to phase out use of medically important antimicrobials for growth promotion in food animals, and phase in more veterinary oversight.

The FDA guidance has been met with cooperation among pharmaceutical companies, many of which committed to the plan in March.

Support for inclusion of antibiotic language in the GRSB guidelines also surfaced in Congress on Monday, as Rep. Louise Slaughter, D-N.Y., submitted a request to McDonalds to primarily source the beef used in its hamburgers from cows raised without antibiotics, reports Christina Marcos for The Hill.

According to Marcos' report, Slaughter suggested similar guidelines for the company's poultry and pork products. The Congresswoman has previously championed a variety of other antibiotic-curbing and food safety measures, including a move earlier this year to withdraw a proposed rule to alter poultry inspection practices.