## 5 Types of Phage-Based Biosensors
### Phage-Based Magnetoelastic Biosensor  
Phage-based magnetoelastic (ME) sensors use a wireless, mass-sensitive technique for the simple, specific, and rapid detection of biological analytes such as \(B\). _anthracis_ spores, _Salmonella_, and _E. coli_ cells on food surfaces [129]. This biosensor consists of a magnetoelastic resonator immobilized with phages that act as bio-probes to recognize the target organism [23]. This sensor detects pathogens by measuring changes in the resonant frequency, which is proportional to changes in the sensor's mass (Figure 6). An ME biosensor is a simple, time-effective, and cost-effective detection platform for foodborne pathogens in different food matrices, and can be a substitute for the qPCR method [130]. This biosensor has been used to detect \(S\). Typhimurium directly on the shells of eggs and various fresh produce surfaces, including tomatoes, spinach leaves, and watermelons [131]. [PERSON] et al. fabricated an ME using filamentous E2 phages specific for the detection of \(S\). Typhimuriumium on fresh spinach leaves. The bacterium was detected after a minimum incubation time of 7 h with a detection limit of 100 CFU/25 g [131]. In another \begin{table}
\begin{tabular}{c c c c c c} \hline
**Transducer** & **Phage** & **Host Bacterium** & **Food Samples** & **LOD (CFU/mL)** & **Ref.** \\ \hline \multirow{8}{*}{Impedimetric Sensors} & T4 & _E. coli_ K12 & NR & \(10^{4}\) & [117] \\ \cline{2-6}  & T4 & _E. coli_ K12 & NR & \(10^{4}\) & [118] \\ \cline{2-6}  & T4 & _E. coli_ K12 & NR & \(10^{3}\) & [105] \\ \cline{2-6}  & Gamma phage & _B. anthracis_ & Water & \(10^{3}\) & [119] \\ \cline{2-6}  & T4 & _E. coli B_ & Water & \(8.0\times 10^{2}\) & [115] \\ \cline{2-6}  & Specific phage & _S. arlettae_ & NR & 2 & [116] \\ \cline{2-6}  & T4 & _E. coli_ K12 & NR & \(10^{2}\) & [120] \\ \cline{2-6}  & T2 & _E. coli_ B & NR & \(10^{3}\) & [121] \\ \cline{2-6}  & CBD & _Listeria_ & NR & \(1.1\times 10^{4}\) & [122] \\ \cline{2-6}  & Endolysin Ply500 & _L. monocytogenes_ & Milk & \(10^{5}\) & [122] \\ \cline{2-6}  & Lytic phage & _Salmonella_ Newport & NR & \(10^{3}\) & [123] \\ \hline \multirow{8}{*}{Amperometric Biosensors} & T4 & _E. coli_ & NR & 1 & [124] \\ \cline{2-6}  & Phage lambda & _E. coli_ & NR & 1 CFU/100 mL & [33] \\ \cline{2-6}  & M13 & _E. coli_ TG1 & NR & 1 & [125] \\ \cline{2-6}  & B1-7064 & _B. cereus_ & NR & 10 & [34] \\ \cline{2-6}  & D29 & _M. snegmatis_ & NR & 10 & [34] \\ \cline{2-6}  & T7 & _E. coli_ & NR & \(10^{2}\) & [126] \\ \hline \end{tabular}  
NR—not reported.  
\end{table} 
Table 2: Some examples of phage-based electrochemical sensors. study, [PERSON] et al. developed an ME biosensor for the detection of _Salmonella_ using the phage C4-22 from the surface of chicken breast fillets in 2-10 min with a detection limit of 7.86 \(\times\) 10\({}^{5}\) CFU/mm\({}^{2}\)[132]. A ferromagnetoelastic biosensor was designed using a tailed _B. cereus_-specific phage as a novel biorecognition tool for the detection of _B. cereus_ in food matrices; however, the application of this biosensor in food samples has not been explored yet [18]. In general, ME biosensors show excellent specificity and sensitivity in pathogen detection and can be used for the real-time detection of target pathogens [132]. Table 3 summarizes the different foodborne bacteria that have been detected using the different types of phage-based micromechanical biosensors. Figure 6: Schematic diagram elucidating the detection principle of the magnetoelastic phage sensor platform.