With the symbolic passing of a small cross made of grape vines, the Rev. Jesse Jackson ended a three-day fast and vowed to wage a continuing boycott against California table grapes. Jackson, who received the cross from Cesar Chavez as the president of the United Farm Workers Union ended a 36-day water-only fast, ended his fast Wednesday and passed the cross to the Rev. Joseph Lowery, president of the Southern Christian Leadership Conference. Lowery, of Atlanta, said he will fast until Saturday, when he will hand the cross to actors Martin Sheen and Robert Blake, who will fast. ``I have fasted with Cesar Chavez,'' Jackson said. ``I have shared the pain. I want to be a better person. I want to be an even more committed person to the workers and the abandoned families who harvest the food we eat.'' Wednesday's ceremony occurred outside a Jewel Co. food store, but Jackson and other demonstrators stressed they were not calling for a boycott of the supermarket chain _ only a boycott of the grapes, which the UFW maintains are treated with pesticides dangerous to farm workers. The union contends pesticides contribute to cancer, miscarriages and birth defects among those who pick grapes. California table grape growers acknowledge that four pesticides are used, but say the same chemicals are sprayed on other vegetables and fruits and pose no health risk. A spokesman for California table grape growers said Chavez is targeting the industry because the union does not have any contracts with growers. ``That's the bottom line,'' spokesman Adam Ortega said from Los Angeles. ``They're accusing stores of selling poisoned grapes. That's not true. They're scare tactics.''