Berlin (CNN) -- Sprouts grown in Germany are the likely source for an E. coli outbreak that has killed 22 people, officials said Sunday.
Gert Lindemann, agricultural minister of Lower Saxony, said there is a "direct link" between a company in the town of Bienenbuettel and "these people getting sick." The firm has been shut down and its products have been recalled, Lindemann said.
It is not immediately clear how the E. coli strain may have gotten into the sprouts, officials said.
Sprouts are bred in large drums.
No E. coli has been found in the company. Authorities say the infection may have taken place too long ago to be found at the company itself. But several restaurants and cafeterias linked to the outbreak got sprouts from the company, officials said.
Two workers at the agricultural company, which was not identified, have come down with severe cases of diarrhea; in at least one of those cases, E. coli was the cause, Lindemann said.
Bienenbuettel is in the district of Uelzen in north-central Germany.
The outbreak of a virulent strain of E. coli has infected more than 2,200 people in at least 12 countries, European health authorities said on Sunday.
All but one of the 22 fatalities were reported in Germany, where officials say it's too early to determine whether the peak of the outbreak has passed. One person in Sweden also died after visiting Germany.
Last week, Spain vehemently rejected suggestions that its cucumbers could be blamed, after the European Food Safety Alert Network said E. coli was found in organic cucumbers originating from Spain, packaged in Germany and distributed to various countries.
In Germany, there have been 627 cases of hemolytic uremic syndrome (HUS) -- a form of kidney failure -- in the current European outbreak, according to the European Centre for Disease Prevention and Control. That's more cases of HUS than in any other recorded outbreak, worldwide.
Fifteen patients in Germany have died of HUS, according to the center, while six died of enterohemorrhagic E. coli, a strain that causes hemorrhaging in the intestines and can result in abdominal cramps and bloody diarrhea.
Reports indicate that an estimated 1,605 people have that E. coli strain so far but do not have HUS, according to the center.
Infections have also been identified in Austria, Czech Republic, Denmark, France, Netherlands, Norway, Poland, Spain, Switzerland and the United Kingdom, according to the organization.
Two women and a man who traveled last month to northern Germany remain hospitalized in the United States with HUS, Chris Braden of the U.S. Centers for Disease Control and Prevention said Friday. A fourth person developed bloody diarrhea, but was not hospitalized, he added.
Two U.S. service members in Germany also developed diarrhea, Braden said. "We have no expectation that this will spread in our country," he added.
The U.S. government website foodsafety.gov says that since 1996, "there have been at least 30 reported outbreaks of food-borne illness associated with different types of raw and lightly cooked sprouts. Most of these outbreaks were caused by Salmonella and E. coli."
The World Health Organization says that in Japan in 1996, "an outbreak linked to contaminated radish sprouts in school lunches caused 9,451 cases" of E. coli.
CNN's Per Nyberg contributed to this report.