Bacteria significantly influence food safety and quality, ranging from beneficial roles in fermentation to causing severe foodborne illnesses. Emphasising the importance of detecting pathogenic Gram-positive bacteria, rapid and reliable detection methods are crucial to mitigate health risks. This chapter discusses the development of electrochemical immunosensors for detecting Gram-positive bacteria in food and drinking water, focusing on nanomaterial enhancements. These immunosensors present an excellent alternative to conventional laboratory methods (e.g. culture methods), molecular methods like Polymerase Chain Reaction (PCR), and immunological-based methods including Enzyme-Linked Immunosorbent Assay (ELISA). This chapter delves into current trends and biosensor designs in recent electrochemical immunosensors. Additionally, this chapter highlights the advantages of using nanomaterials to improve sensitivity and specificity, providing insights into how these advanced technologies can be integrated into food safety practices for better monitoring and control. Specifically, immunosensors for direct detection of S. aureus, L. monocytogenes, and B. cereus that are recently developed are discussed.