Bertolli and Filippo Berio brands of olive oil together account for more than half of the $230 million sales in supermarkets nationally. They also dominate the market in the Boston area, where Brand Marketing spot-checked prices at three supermarkets. Purity, Omni Foods and Johnnie Foodmaster each priced the 17-ounce bottles of Bertolli Extra Light olive oil slightly higher than Filippo Berio Extra Mild. The latter brand trails Bertolli in market share nationally, but holds a commanding share lead -- 49% to 10% -- over Bertolli in Boston.
