A U.S. senator and two U.S. representatives from Maine provided free promotion for their state’s potato growers when they asked owners of Five Guys Burgers and Fries restaurants to use Maine potatoes.

Sen. Olympia Snowe and Reps. Chellie Pingree and Mike Michaud wrote to the owners of five franchises asking them to use Maine spuds in their restaurants. The elected officials cited lower transportation costs and fresher food as two reasons the restaurants should opt for Maine potatoes.

The only Five Guys restaurant in Maine is in Portland.

A company spokeswoman told the Portland Press Herald that there is a plan to open another franchise in Bangor this spring.

She said franchise owners do not decide where to source potatoes. Franchise owners must buy potatoes from distributors chosen by the corporation, which is based in Lorton, Va.

The spokeswoman, Molly Catalano, said Five Guys sources potatoes from Idaho, Washington and Oregon for restaurants in the U.S. Potatoes from Prince Edward Island and other Canadian provinces are used at the chain’s restaurants in Canada.

Catalano said the corporation is considering using potatoes from Maine in the future, and that Five Guys officials believe the best french fries come from potatoes grown above the 42nd parallel.