There should be no problem with McDonald's fries for anyone who is lactose 
intolerant. Dairy derivatives should not contain any lactose. And people who are 
lactose intolerant will not respond to a few residual molecules the way those 
with severe dairy allergies respond to tiny amounts of protein molecules. 
They're entirely different situations.

What I'm waiting for, along with everybody else, is for McDonald's to 
announce the exact composition of these wheat and dairy derivatives. Only then will 
allergic people know the full story.

Steve Carper
Steve Carper's Lactose Intolerance Clearinghouse
Planet Lactose Blog