BIENENBUETTEL, Germany (Reuters)—German scientists were working on Monday to confirm an organic vegetable farm as the source of an outbreak of E. coli bacteria that has already killed 22 people and caused a food scare across Europe.

The relief in Germany that investigators had found a possible source of the killer bacteria—ironically in bean sprouts, eaten by many as "health food"—was tempered by reports of mounting losses for vegetable farmers and retailers across Europe caused by three weeks of panic.

In Brussels, the European Commission said it would hold a special meeting of E.U. farm ministers in Luxembourg on Tuesday. One E.U. source told Reuters the ministers would discuss financial aid to fruit and vegetable producers hit by the E. coli crisis.

The manager of the north German farm at the center of the inquiry said he could not understand how it could be the source of an infection that is usually transmitted through feces, or food or water contaminated with fecal bacteria.

The Shiga toxin-producing E. coli (STEC) strain found in this outbreak is known to be able to lurk in cows' intestines.

"I can't understand how the processes we have here and the accusations could possibly fit together," Klaus Verbeck told the regional newspaper Neue Osnabruecker Zeitung.

"The salad sprouts are grown only from seeds and water, and they aren't fertilized at all. There aren't any animal fertilizers used in other areas on the farm, either."

Scientists say the contamination may have been on or in the bean seeds themselves, in the water used to grow them, or come from a worker handling them.

Farm shut

German officials said on Sunday that Mr. Verbeck's bean sprouts could be behind an E. coli outbreak that has killed 22 and made more than 2,300 people ill across Europe. The farm has been shut and produce has been recalled.

"We've got clear indications that the company...is the source of the infection, but we've got to wait for confirmation from laboratory tests," Health Minister Daniel Bahr told German ARD television.

Neither Mr. Verbeck, himself a vegetarian, nor anyone else from the farm would talk on Monday to journalists and television crews, including Reuters, outside his farm in Bienenbuettel, Germany, a town of 6,600 people about 40 miles south of Hamburg.

German officials, under intense pressure to identify the source of the outbreak, have been warning consumers for weeks to avoid tomatoes, cucumbers and lettuce, and at one stage said Spanish cucumbers might be the source. The hitherto unknown strain of E. coli has killed 21 Germans and one Swede.

In Geneva, the World Health Organization said it was awaiting more information from the Robert Koch Institute, the German institute for disease control.

"Association with contaminated fresh products seems the most likely culprit, but we are still considering a wide range of possibilities," said Claudia Stein, director of information, evidence, research and innovation at the WHO's European office.

The health emergency has strained ties between E.U. members Spain and Germany and led Russia to ban imports of E.U. fruit and vegetables.

Raw bean sprouts are popular among Germans and are often added to salads or sandwiches. Spanish farmers say lost sales have been costing them €200 million ($292.7 million) a week, and officials said they might claim compensation. The crisis could put 70,000 people out of work in Spain, which already has the highest unemployment in the E.U.

The outbreak has affected people in 12 countries—all of whom had been travelling in northern Germany. Many have developed hemolytic uremic syndrome (HUS), a potentially fatal complication attacking the kidneys.

"Bean sprouts are very frequently the cause of outbreaks on both sides of the Atlantic," said Paul Hunter, a professor of public health at Britain's University of East Anglia.

"They're very difficult to grow hygienically, and you have to be so careful not to contaminate them."

He said organic farms often carried an extra risk of contamination because they shunned nonorganic chemicals.

In Japan, at least 11 people died in 1996 in an E. coli outbreak linked to contaminated radish sprouts.

Organic producer

In Bienenbuettel, two uniformed security guards were patrolling behind the closed driveway gate to the farm located in idyllic countryside.

One neighbor, Sibylle Lange, said she knew Mr. Verbeck well and that he had been in organic farming for many years.

"These are very serious, hardworking people who were very early producers of organic products," Ms. Lange, a 45-year-old mother of two, told Reuters.

"They've been working here for some 30 years. It's a high-quality product. I've eaten all sorts of vegetables from here—bean sprouts included—and they taste delicious. I can't imagine the source could come from here. The whole thing has deeply affected us in the neighborhood and our friends."

The Lower Saxony state agriculture minister, Gert Lindemann, said on Sunday evening investigators had traced the rare, highly toxic strain of the bacteria to a farm in the Uelzen region, later identified in the media as the farm in Bienenbuettel.

He said bean sprouts, alfalfa sprouts, mung bean sprouts, radish sprouts and arugula sprouts from the farm might all be connected to the outbreak.

The rare STEC strain of E. coli can stick to intestinal walls, where it pumps out toxins, sometimes causing severe bloody diarrhea and kidney problems. Some patients have needed intensive care, including dialysis.