As America's food system became increasingly industrialized in the twentieth century, it became increasingly difficult for the Jewish community to regulate the foods it ate to comply with kosher law. As American Jews strayed from religious lives, major Orthodox Jewish organizations sought to win back adherents by adapting the ancient ritual of Jewish dietary law to the most complex, modern processing techniques. The result was an elaborate third-party certification system, the first of its kind, which is now the backbone of a billion-dollar industry that thrives today. Within a short span of time, major food corporations were printing kosher certification labels on their packages. Today, two-fifths of food sold in the supermarket come kosher certified. How Jews eat—purchasing packaged products with kosher seals of approval—has fundamentally transformed from the immigrant days on the Lower East Side and the shtetls of Eastern Europe. Consequently, kosher food has become overly reliant on large-scale food production. Small efforts to further adapt the kosher industry to small-scale production and fair-labor rights are underway, though a long way off.