Book excerpt: Environmental pollution and food safety are becoming serious concerns to human health in developing countries. To combat such issues, researchers have developed different approaches for on-spot detection and screening of infectious disease, caused by pathogens and toxins in food and water samples. One such approach is the development of phage- and phage-component-based sensors that are highly specific, sensitive, rapid, efficient, cheap, and portable analyte screening platforms. Such sensors overcome the limitations of conventional screening approaches. This chapter highlights different food and environmental contaminations and represents the potential of phage-based biosensor for bacterial detection. It summarizes different applications of phage-based sensors in the fields of food safety and environmental monitoring and highlights current challenges and perspective. In general, this chapter brings together the technologies related to phage-based sensors and food and environmental safety, by compiling the efforts of engineers and scientists from multidisciplinary areas.