Tainted tomatoes sicken 25 in Md.

The latest count is twice the number of cases reported a week ago.

The rising numbers are attributed to improved surveillance for salmonella and lab tests confirming the same strain, not new infections, CDC said.

 The outbreak is unusual in how long it is lasting, as most food-borne illnesses taper off after about a month, and the source is identified quicker, said Jerry Brust, integrated pest management agent for the University of Maryland’s extension office.

“I am surprised it’s still hanging around. I figured it would have died out or disappeared,” he said. “It keeps hanging on and hanging on.” Brust said he doesn’t expect the numbers to climb much more. It takes weeks to test for salmonella and determine if it’s the same strain.

U.S. Food and Drug Administration officials traced the path of some of the tomatoes to certain farms in Mexico and Florida, but haven’t identified the sources.

Millions of tomatoes are circulating in stores nationwide, making it difficult for officials to pinpoint the culprits, said Alan Brench, chief of the Maryland health department’s division of food processing. “The numbers are not working for us,” he said.

At least 95 people have been hospitalized for this strain of salmonella, but no deaths have been attributed to the outbreak, the CDC reports. One Texas man who died from cancer had salmonella when he died, which may have contributed to his death.

Salmonella can cause fever, diarrhea and abdominal cramps, according to the CDC. A small number of people with salmonella develop joint pain, irritation of the eyes and painful urination, a condition called Reiter’s syndrome, which can last for months or years, and lead to chronic arthritis, the CDC said.

The outbreak has been linked to raw plum, Roma and round tomatoes.