One drop of water can hold one million bacteria. Bacteria are single celled organisms that can be found in almost all environments on our planet.

Bacteria are crucial for many plants, animals (including humans), and our survival cannot be separated from them.Each bacterium is an independent cell, and bacteria are simple small organisms.
Foodborne pathogens primarily refer to pathogenic bacteria that use food as a transmission vehicle. These pathogens can survive in food or water sources, and after consumption, may lead to intestinal diseases or food poisoning, potentially resulting in death in severe cases.
Common foodborne pathogens include Bacillus cereus, Vibrio parahaemolyticus, Staphylococcus aureus, Salmonella, Campylobacter jejuni, Listeria monocytogenes,and Escherichia coli. Traditional culture-based methods are currently the gold standard for bacterial detection, being both inexpensive and accurate, but are limited by their labor-intensive, time-consuming, and low-throughput nature.
In recent years, many technologies have been developed for rapid and sensitive detection of pathogens, with nucleic acid-based detection and immunoassays being the most commonly used.
However, nucleic acid methods based on polymerase chain reaction (PCR) typically require expensive equipment and trained operators. Traditional enzyme-linked immunosorbent assay (ELISA) is time-consuming and relatively low in sensitivity.
Therefore, it is important to develop a rapid, sensitive and stable bacterial detection method. In this study, we present a novel colorimetric biosensor for the direct detection and subsequent inactivation of foodborne pathogenic bacteria. Then, based on the relationship between red-green-blue (RGB) values and bacterial concentration, a mobile app was developed to visualize the bacterial detection effect, which can directly generate bacterial concentration values. Finally, the pathogenic bacteria were killed by the biosensor by generating light and heat in the near infrared.