## 6 Conclusions and Future Directions
In addition, the ability of phages or their proteins to be immobilized on the surface of sensor platforms through chemical anchoring or physical absorption is well developed; however, their stable attachment on other surfaces is a fertile topic for research exploration [12]. While the specificity of bacteriophages towards a host/target bacterium is the basis for the development of phage-based biosensors, there is a need for broadening the detection range for multi-pathogen detection. Introducing polyvalency to RBPs has become relevant to establishing a multiplexed platform for the rapid detection of foodborne pathogens, which is an area that has yet to be addressed [139]. In this review, a description of nearly 54 biosensors has been summarized. Though the detection limits and validation with samples for the majority of these sensors are known (Tables 1-3), many researchers failed to provide such information. These might be due to the lysis of the target bacterium by bacteriophages or interference from the food samples, which consequently could have obscured the accuracy of bacterial counts. In addition, the drying of biorecognition molecules on the sensor platform may have resulted in the loss of the captured target bacterium, which could have also affected detection. To overcome such limitations, genetically modified phages and/or advanced functional surface chemistry can be employed for stable phage immobilization. Phage-based biosensors have been demonstrated to have great potential in the detection of pathogenic bacteria from food and the environment. However, the transition from the laboratory bench to commercial spaces has been very slow due to several constraints, including, but not limited to, a weak signal-to-noise ratio, sensitivity, and specificity of the bacteriophages; reproducibility; a short shelf-life of the sensor; instrument design; and cost. The future advancement of phage-based biosensing platforms should also consider the development of new recognition platforms, improvements to signal amplification, and the establishment of nanostructures for the precise geometry of the sensor design. To this end, genetically modified phages are relevant since they can produce the desired peptides and proteins on their surface to generate an appropriate and multifunctional biorecognition platform. Furthermore, one of the most promising future directions of phage-based sensing is its compatibility with emerging biomolecules and nanostructures (quantum dots; metallic, magnetic, and polymer nanoparticles; etc.) to generate new and innovative phage-based nanodevices or bioinspired sensor tools. Such hybrid versatile sensors are well-suited for the detection of a wide variety of foodborne pathogens from various sources. In conclusion, even though the progress made so far has been inspiring, the future of phage-based sensing still requires a strong collaborative effort between researchers working in diverse disciplines, such as molecular biology, microbiology, biochemistry, engineering, material science, biology, physics, and chemistry, to enhance the overall detection efficiency of the sensors. Moreover, care must be taken to avoid any potential public health hazards associated with the bacteriophages and the spread of the parental host (pathogenic bacteria) during bacteriophage production, purification, and storage. Conceptualization and contribution to writing, R.R.A.-H., A.K.B., A.D.T., T.A., S.H., I.Q., M.G.A., B.M.A., I.A. and S.A.A. All authors have read and agreed to the published version of the manuscript. This research was funded by Institutional Fund Projects, grant number IFPRC-109-130-2020; the Ministry of Education; King Abdulaziz University, Jeddah, Saudi Arabia; and the USDA National Institute of Food and Agriculture, hatch accession no. 1016249. Not applicable. This research was funded by Institutional Fund Projects under grant number IFPRC-109-130-2020.