The main species are Escherichia coli, Enterobacteriaceae, Citrobacter and Klebsiella.
Coliform group is not named after bacteriological classification, but a term in the field of sanitary bacteria. It does not represent a certain bacteria or a certain genus, but refers to bacteria with certain characteristics related to fecal pollution. These bacteria are not completely consistent in biochemistry and serology.
Escherichia coli is widely distributed in the feces of warm-blooded animals and in nature. According to scientific research, coliforms generally exist in the feces of warm-blooded animals, places where people often move and places polluted by feces. The pollution of human or livestock manure to the external environment is the main reason for the widespread existence of coliforms in nature. And most of the feces are Escherichia coli.
Coliform bacteria are mainly used as indicators of fecal pollution, and we mainly evaluate whether there is fecal pollution in food according to the detection of this flora. The number of coliforms not only indicates the degree of fecal pollution, but also reflects the possible harm of bacteria to human health. Feces are human excreta, including those of healthy people, patients with intestinal dysfunction and even carriers. Therefore, in addition to normal bacteria, there may be some intestinal pathogens such as Salmonella and Shigella in feces. Therefore, we can infer the possibility of intestinal pathogenic bacteria pollution in food based on fecal pollution in food. Once you carry too much intestinal flora, it means the threat of food poisoning and epidemic disease lurks.