Solar cookers and microbiology are two topics that Solar Cookers International (SCI) founding member and current board member Bob Metcalf has been passionate about for over two decades. Using the principles and methods from food microbiology, which Metcalf teaches at California State University, Sacramento, he has developed the Portable Microbiology Laboratory (PML) for water testing and the Water Pasteurization Indicator (WAPI) to aid in the process of pasteurizing water with solar energy. Both these innovations have been incorporated into SCI's Kenya projects to improve public health.