Food production processes are increasingly influenced by quality and safety concerns. For dairy production, one of the food quality outcomes is a low level of bacteria in unprocessed milk. A putative on-farm control point for low levels of bacteria is teat and udder cleaning before milking. Currently there are no appropriate on-farm schemes to monitor the effectiveness of different processes used to prepare cows for milking. The purpose of this project was to compare levels of teat skin bioluminescence with direct bacterial culture as a tool to evaluate teat cleanliness of dairy cows. Bioluminescence demonstrated average changes in cow cleanliness as animals proceeded through the premilking sanitation steps and, in that manner, could be used as a tool to demonstrate the effectiveness of the process.