Hannah Young, a community health worker for Hennepin County, on Wednesday showed how water samples are collected at Wayzata Beach.

Each week during the summer, between Memorial Day and Labor Day, workers with Hennepin County's Public Health Department take samples of water from 31 public swimming beaches.

The samples are then analyzed for traces of E. coli, a bacterial organism in untreated waste that can cause stomach aches, diarrhea, flu-like symptoms and even some ear and eye infections.

If E. coli levels exceed federal standards, county officials can close a beach until follow-up samples return to safe levels.

For more information on Hennepin County beaches, go to www.hennepin.us/beaches/.