McDonald’s is expanding its market test of selling fresh beef patties instead of frozen patties. It is now selling them in 75 locations in northeast Oklahoma, reports Fortune. The initial test began in May with 14 Dallas-area locations. The fresh patties are currently being used for just its Quarter Pounder burgers.

Fortune notes that the company would have to undergo substantial changes if it were to switch to fresh beef at its 14,000 U.S. locations.

“But on the bright side, this expansion means the initial test went well, so now McDonald’s will see if it’s something it can sustain on a larger scale,” it adds.