Dairy firms, especially in Wisconsin, became alarmed at the potential threat to their business and by 1902, succeeded in getting legislation passed to prohibit the coloring of the stark white product. In response, the margarine companies distributed the margarine together with a packet of yellow food coloring. The product was placed in a bowl and the coloring mixed in manually. This took some time and effort, and it was not unusual for the final product to be served as a light and dark yellow, or even white, striped product. During World War II, there was a shortage of butter in the United States, and "oleomargarine" became popular. In 1951, the W.E. Dennison Company received for a method to place a capsule of yellow dye inside a plastic package of margarine. After purchase, the capsule was broken inside the package, and then the package was kneaded to distribute the dye. Around 1955, the artificial coloring laws were repealed, and margarine could once again be sold colored like butter.