Canada has developed a new type of Food Packaging that can change color when food contains pathogenic bacteria, pesticides and other ingredients. The food package is divided into several layers: the first layer that comes in direct contact with food is a porous layer, and pathogenic microorganisms can pass through this layer and then reach the gel layer; the gel layer contains antibiotics mixed with color compounds, and bacteria After exposure, colored antibiotics are activated and enter the outermost packaging layer, which binds to other antibodies coated on invisible warning signs. In this way, the logo appears, reminding consumers not to purchase the product. According to "Phoenix Satellite TV," the antibodies used in this package are very common, and the laboratory often uses them to detect four kinds of bacteria that can cause food poisoning, namely Listeria, Salmonella, E. coli O-157 and Campylobacter. However, this type of packaging does not detect low levels of bacteria, and some experts worry that consumers may be misled.