FBI agents confirmed that they are investigating several cases in the Fresno area in which glass was found in packages of Knudsen cottage cheese. Knudsen has recalled more than 600,000 pounds of cottage cheese since the first discoveries of glass fragments were reported more than a week ago in Southern California. All of the containers involved in the case are believed to have come from the Knudsen plant in Visalia. Phyllis Luna told authorities that she found a glass fragment the size of a fingernail in cottage cheese she purchased at a market on Fresno's southeast side. She said she discovered the glass when she bit down on it but was not injured. Investigators said they are investigating in the Fresno area, but six FBI agents are working on the case to determine whether the glass found its way into the cottage cheese deliberately or accidentally.