The park board will sample the water at the beaches again on Wednesday.
11 Minnesotans have been confirmed to have had the infection.
There's a risk of a specific product containing a strain of E. coli.
The late July, early August outbreak has impacted dozens.
Beaches usually re-open with 24-48 hours after bacteria-related closings.
Karen Odens died on Saturday, July 14.
Only California and Pennsylvania have reported more cases.