Donald Kennedy, former FDA commissioner and president emeritus at Stanford University, is one of 150 scientists that have asked the FDA and Congress to look at the human health issues connected with the overuse of antibiotics in animal agriculture, and for both agencies to work together to resolve the critical situation.

European health officials are now warning that the German dioxin outbreak may be worse than previously thought - extending beyond tainted eggs - and prompting some countries to take harsher action.

The dioxin scare surfaced after 3,000 tonnes (over 6,600 pounds) of an animal feed additive sold in Germany were discovered to contain trace amounts of dioxin, causing officials to ban many farms from selling eggs.