Amazing, I never knew! But checking around the web I find there are such laws, "which make it illegal to question the safety of any food product without verifiable scientific proof. Known as 'veggie libel' or 'banana bills,' the laws have been enacted in a dozen states since 1991."
I guess that explains why I haven't seen the headline that I have long anticipated in connection with the current brouhaha over E. coli-saturated spinach: "Eat Shit and Die!"
Carl