 It appears a medical mystery has at least been partially solved. Federal health officials say a Florida cucumber grower that used untreated water is one likely source of salmonella food poisoning that sickened nearly 450 people this spring. The water used by Bednar Growers of Boynton Beach, Florida, matched a strain of the bacteria that caused some but not all of the illnesses reported in more than 30 states and Washington, D.C. from late March through early June.