Answer: 1. Classification of food poisoning can be divided into four categories according to pathogenic substances.

(1) Bacterial food poisoning: refers to poisoning caused by ingesting food containing a large number of bacteria or bacterial toxins, and is the most common type of food poisoning. The incidence rate is usually high, and the mortality rate of most bacterial food poisoning is low. The number of poisoned bacteria is relatively large, and the incidence has obvious seasonality. May to 10 is the most, mainly including salmonella food poisoning, Vibrio parahaemolyticus food poisoning and Clostridium botulinum food poisoning.

(2) Food poisoning caused by fungi and their toxins: Food poisoning caused by eating food contaminated by toxic fungi and their toxins has a high morbidity and mortality, and the seasonality and regionality of the disease are obvious. For example, moldy sugarcane poisoning is very common in northern China in early spring.

(3) Poisonous animal and plant poisoning: refers to poisoning caused by eating poisonous animals and plants by mistake or ingesting animals and plants whose toxic components have not been removed due to improper processing and cooking, such as food poisoning caused by puffer fish, toadstool, cassava, green beans and sprouted potatoes, with relatively high incidence and obvious seasonal and regional deaths. For example, puffer fish poisoning mostly occurred in the late Qingming period, at the junction of rivers and seas, with a high mortality rate. Poisonous mushroom poisoning is more common in warm and humid seasons in spring and autumn, and the mortality rate is higher in hilly areas.

(4) Chemical food poisoning: refers to poisoning caused by eating toxic chemicals by mistake or eating food contaminated with chemicals. The seasonality and regionality of the disease are not obvious, but the incidence and mortality are relatively high. For example, food poisoning caused by organophosphorus pesticides, certain metals or metalloid compounds, nitrite, etc.

2. Characteristics of food poisoning Although the causes and symptoms of food poisoning are different, the incidence has the following characteristics:

(1) The incubation period is short, the onset is sudden, the momentum is fierce and explosive, and most people may get sick in a short time.

(2) The clinical manifestations of all poisoned patients are basically similar, and the most common symptoms are digestive tract symptoms, such as nausea, vomiting, abdominal pain and diarrhea. And the course of disease is short.

(3) The occurrence of food poisoning is related to food and has a clear relationship. Poisoned patients have eaten the same poisoned food in a similar time, and those who have not eaten are not poisoned.

(4) Patients are not contagious to healthy people, so if they stop eating toxic food, the disease will stop soon.

(5) The incidence curve suddenly rises and then suddenly falls, and there is no sequela, which is different from infectious diseases.