What about reports that radioactivity had already gotten not only spinach and milk but also into the water supply?

FORBES: Putting Numbers On Japan's Radioactivity Risk

They have scoured the company's processing plant as well as the farms that grow the spinach, looking at everything from irrigation water to the proximity of livestock, with no sure connections made so far.

ECONOMIST: Those healthy green leaves cause a terrible scare

Experts have come up with all sorts of hypothetical ways the E. coli could have gotten into the spinach, from manure that wasn't properly composted to runoff from cattle farms to contaminated irrigation water.

FORBES: Magazine Article