In the wake of the pet-food poisoning scandal, some of the biggest U.S. food manufacturers—Tyson and Mission Foods—have banned Chinese ingredients. But since China is the world's biggest supplier of the flavorings, vitamins and preservatives that are used in virtually all processed foods, the bans may be impossible to uphold, the LA Times observes.
Take the Hostess Twinkie, for example. Of 39 ingredients, the Times notes, at least half a dozen—including vitamin B compounds, the preservative sorbic acid and red and yellow colorings—are most likely made in China. Additives are made by many small, largely unregulated companies, and the major food manufacturers here often don't know where they come from.