Abstract：Food safety and security is a key public issue. The best way to prevent the diseases related to foodborne pathogenic microorganisms is to detect their presence in food chain at its earliest stage. Therefore, various biosensors have been developed to tackle the food safety. In general, a biosensor has three units: biomolecular recognition unit, transducer, and reading unit. The biomolecular recognition unit can be antibody, enzyme, phage and protein. The reading unit can be a computer or cellphone or special electronic device. The transducer uses different physical phenomena. Based on the transducer used, all the biosensors can be classified into acoustic, electronic, magnetic, mechanical, optical and electrochemical based transducers.