The first tests from a north German farm suspected of being the source of an E. coli outbreak are negative. Officials said, of 40 samples from the farm being examined, 23 tested negative. Earlier, they said that bean sprouts produced at the farm in Uelzen, south of Hamburg, were the most likely cause of the outbreak. The outbreak, which began three weeks ago and is concentrated in Hamburg, has left 22 people dead. Initially, German officials had pointed to Spanish cucumbers as the probable cause of the illness.