Consumer food prices will climb in 1991 at a much slower pace than they did this year, the Agriculture Department predicted Tuesday.

James R. Donald, chairman of the department's World Agricultural Outlook Board, said the 1991 forecast calls for a food price increase of 2 percent to 5 percent, compared with almost 6 percent this year."Projected record meat supplies, higher dairy product output and the likelihood of bigger citrus crops this season will moderate food price rises," he said.

Further, Donald said in a paper delivered at the department's annual outlook conference, food marketing costs will rise more slowly if overall inflation eases to around 4.5 percent instead of this year's 5.5 percent to 6 percent.

Donald said farmers will expand 1991 plantings of several crops to take advantage of more acreage flexibility under new farm program provisions.