U.S. regulators are telling consumers not to eat bagged spinach at all, even after washing it, as an outbreak of E. coli spreads to a ninth state.

Washing the spinach won’t make it safe because the E. coli bacteria are sticking so tightly. "If you wash it, it is not going to get rid of it," Robert Brackett, director of the FDA’s Center for Food Safety and Nutrition, told the Associated Press and CBC News.

So far, there is no indication where the problem started, and no particular brand identified as dangerous.

There is no indication so far that E. coli has contaminated spinach in Canada, said René Cardinal, acting national manager for fresh fruits and vegetables at the Canadian Food Inspection Agency. The FDA will keep the Canadian agency informed of the progress of its investigation.