Foodborne bacterial infection poses a serious threat to human health. As most diseases are caused by living bacteria, real-time assessment of bacterial viability is vitally important to the public health sector. Herein, we developed a simple and novel colorimetric assay based on the Glucose oxidase (GOD)/Horseradish peroxidase (HRP) bienzyme system for real-time monitoring of bacterial viability in food and drinking water. This bienzyme system is free of any chemical synthesis and only requires 3 sample handling steps. The color response is easily observable with the naked eye or recordable with a smartphone for precise determination of bacterial viability. The proposed strategy was validated with various bacteria both Gram-positive and Gram-negative, indicating its capability for broad-spectrum bacteria viability detection. Therefore, the proposed strategy shows promise for rapid and reliable quality control in food and drinking water.

The use of sensors in critical areas for human development such as water, food, and health has increased in recent decades. When the sensor uses biological recognition, it is known as a biosensor. Nowadays, the development of biosensors has been increased due to the need for reliable, fast, and sensitive techniques for the detection of multiple analytes. In recent years, with the advancement in nanotechnology within biocatalysis, enzyme-based biosensors have been emerging as reliable, sensitive, and selectively tools. A wide variety of enzyme biosensors has been developed by detecting multiple analytes. In this way, together with technological advances in areas such as biotechnology and materials sciences, different modalities of biosensors have been developed, such as bi-enzymatic biosensors and nanozyme biosensors. Furthermore, the use of more than one enzyme within the same detection system leads to bi-enzymatic biosensors or multi-enzyme sensors. The development and synthesis of new materials with enzyme-like properties have been growing, giving rise to nanozymes, considered a promising tool in the biosensor field due to their multiple advantages. In this review, general views and a comparison describing the advantages and disadvantages of each enzyme-based biosensor modality, their possible trends and the principal reported applications will be presented.