Six envelopes sent to the Pine County Government Center in Pine City, Minn., on Tuesday contained not only a flour-like powder but a certain bacteria, too, officials said Friday.

It's unclear, until more testing is complete in the next two weeks, whether the bacteria is Bacillus thuringienses or Bacillus cereus, health department officials said.

The later can cause foodborne-illness symptoms including diarrhea and vomiting, usually within 24 to 48 hours of exposure, according to the Public Health Laboratory of the Minnesota Department of Health.

The powder touched off safety protocol that included evacuating about 200 workers, visitors and jurors, and shutting down the Government Center, including jury trials, for hours on Tuesday afternoon.

The Government Center reopened on Wednesday.

Finding the bacteria in flour or a similar food substance wouldn't be unexpected, officials said Friday.

It is a "very common bacteria around farms," said Steven Blackwell, Pine County chief sheriff's deputy.

A standard cup of flour, for instance, can contain dozens of bacteria, Blackwell added.

This situation is serious, he said, because the substance was intentionally sent to the Government Center.

The case has been turned over to the FBI to investigate, he said Friday evening.

Envelopes discovered

The disruptions began on Tuesday afternoon, when a worker in the District Court office opened one envelope, spotted a powdery substance and notified authorities.

The six plain but similar envelopes, with typed addresses, were isolated to two locations in the Government Center, he said.

The St. Paul Fire Department's hazardous materials team initially worked to identify the substance and the Minnesota Department of Health (MDH) subsequently ran more tests, looking for potential chemical or biological threats. "MDH tests ruled out bioterrorism organisms," a news release said.

The final test results are expected in about two weeks.

Pine County officials had urged those who were in the courthouse on Tuesday to see physicians if they suffer unusual symptoms and to reduce further exposure by showering and washing clothes worn there that day.

Joy Powell • 612-673-7750