Sedgwick and Batchelder were among the first to count bacteria in milk. Their pioneering work in Boston, from 1890 to 1892, was a revelation and their method was quickly followed by others. In 1990 New York was the first city to use this approach as a basis for setting a bacteriological standard for ordinary market milk, at one million bacteria per cubic centimeter. It was even more difficult to enforce than compositional standards because there was not necessarily any implication of cheating, just bad practice, and, anyway, who was responsible for the contamination? Boston followed, in 1905, with the tougher threshold of 500,000 bacteria per cubic centimeter, and then Rochester in 1907 with 100,000. By the outbreak of the First World War over 20 American cities were counting bacteria in their milk supplies.
- Atkins, Peter. Liquid Materialities: A History of Milk, Science and the Law. New York: Ashgate Publishing; Routledge, 2010.