E. Coli from Cow Manure Plant Pots?

I bought pots made from cow manure with impatiens in them, but with the recent E. Coli scare in Europe, I'm concerned that the pots could be infected with the bacteria. Is it safe to plant these in a garden? We have a pet dog and we're concerned about her getting sick from them. We're also trying to grow tomatoes in the vicinity of the cow pots.