The Best Retail Initiative award was presented by their Royal Highnesses the Prince of Wales and the Duchess of Cornwall.
The brand was launched by BFS nearly two years ago from its Bodmin depot. It promotes Cornish growers and gives better financial returns for top-quality produce.
BFS joint managing director Nick Matthews said: "We're delighted to have won. It reflects the hard work that our growers and the BFS team have put in."
Growfair sources from more than 25 Cornish growers and this summer it was successfully launched in Wales and Devon.