Anyone with a unwheming belief in the power of the free market ought to take a look at "Swindled - The Dark History of Food Fraud from Poisoned Candy To Counterfeit Coffee" by Bee Wilson. ISBN-13: 978-0691138206.
Not so long ago, left to the market, Pickles were green from toxic copper, children's sweets gained their bright colors from lead and other poisons, and the white bread of the upper crust was often bleached with alum.
Nor sadly does government legislation solve everything - Wilson makes it clear that watering down, coloring up, bulking out, and plain poisoning are still with us, as are dyes, flavorings, and the catch all 'additives'. Even labeling is of limited use as it has not been kept upto date.
Advertisers continue to con people with for example highlighting "low fat" while not mentioning the high salt and sugar they have replaced the fat with. Buyer beware indeed !