Researchers say a strain of E. coli found last week on Dutch beet sprouts has not been seen before in the country and they have sent samples for further analysis at labs in Italy and Denmark.

The Dutch Food Safety Authority says nobody appears to have been sickened by the strain.

Health Minister Edith Schippers says the fresh round of tests will likely take weeks.

Friday's announcement came a day after Germany's disease control center said the death toll in Europe's outbreak of a separate strain of E. coli had risen to 39 after one more patient died. The Robert Koch Institute, however, says the number of new infections is continuing to tail off.

The killer strain has been traced to sprouts from an organic farm in a northern German village.