Foodborne illness associated with pathogens, toxins, and other contaminants can cause serious health problems that are dangerous for humans. Owing to the presence of sufficient nutrients in dairy products, they are recommended on a regular basis. However, these nutrients promote the development of pathogens that lead to foodborne illness. Over the past few years, researchers have focused more on determining the presence of live foodborne pathogens in dairy products. Biosensors, which can convert biological, chemical, or biochemical signals into measurable electrical signals, are innovative methods for quickly identifying foodborne pathogens in the food industry. One of the most widely used types of sensors is the immunosensor, which is mainly used in food safety, environmental monitoring, and diagnostic areas. Researchers have developed various rapid, accurate, and affordable biosensor-based analytical tools to identify milk-borne pathogens that could help the dairy industry reduce costs and improve production management. The current chapter aims to provide an overview of various nanomaterial-based immunosensors for the detection of several foodborne bacterial toxins and contaminants, emphasizing their principles, benefits, and drawbacks in terms of sensitivity, multiplexing capability, and simplicity in milk samples. It also focuses on the application of these sensors for the determination of pathogenic bacteria in food samples.