The Robert Koch institute said Tuesday no one has fallen ill for three weeks -- a period that covers the disease's incubation time.

There were 52 deaths in all -- 50 in Germany and one each in Sweden and the U.S. that made it the world's deadliest e coli outbreak.

The bacterial strain involved caused an unusually high number of cases of a severe complication that can lead to kidney failure. A total of 4,321 people fell ill in Germany -- 852 with that complication.

There were some 140 more cases in 15 other countries.

The outbreak was traced in early June to a vegetable sprout farm near Hamburg. European authorities later said one batch of Fenugreek seeds from Egypt was probably the source.