Enzyme-based biosensors have potential application in the agro-food analysis, within three main areas that are food safety, food quality, and process control. Enzyme-based biosensors may be classified according to the analytes or reactions that they monitor, for example, direct monitoring of analyte concentration of reactions producing or consuming such analytes is the direct mode. In enzyme-based biosensors, the enzyme reacts selectively with its substrate. To prepare the biosensor, the enzyme has to be immobilized in a thin layer at the surface of the transducer. Biosensors based on the principle of enzyme inhibition have by now been applied for a wide range of significant analytes such as organophosphorous pesticide (OP), organochlorine pesticides, derivatives of insecticides, heavy metals, and so on. Enzyme-based biosensors have been developed both with potentiometric as well as amperometric transducers. In this chapter, an example of the use of disposable graphite sensor based for food analysis is described.