Why isn't New York City's tap water kosher? What makes the corner gyro stand halal? Where do the two standards agree and what sets them apart? For today's Please Explain we dive into the rules and regulations of dietary laws. We are talking to Lara Rabinovitch, food editor at GOOD Magazine and self-styled "Doctor of Pastrami," Rabbi Avrohom Marmorstein, director of Mehadrin Kashrus, and Mohammad Adil Khan, president and founder of the US Halal Association.