How does a food receive kosher approval? For some items, like the prohibition of pork, the Torah is comparatively clear. But what about a more modern food like Jell-O which contains gelatin, a substance derived from forbidden bones and hides of animals, but has been turned into a chemical that no longer has much, if any, relationship to its origin? Some rabbis would give Jell-O a kosher stamp. Now, what if the hide used to make the chemical called gelatin was a pig’s? Kosher USA if nothing else is provocative and at its best points to centuries of rabbinic debate still alive as food becomes more and more processed. Horowitz’s academic style and heavy emphasis on the political interplay of corporations and rabbis are sparsely balanced by personal anecdotes, which in many instances, are more captivating than the long passages of textbook-like replays of angry letters between generally conservative rabbis supporting modernization and orthodox rabbis insistent upon glatt kosher laws that adhere to Torah but are indifferent to animal suffering or worker rights.