First, the concept and characteristics of bacterial food poisoning

Concept

Bacterial food poisoning refers to food poisoning caused by ingestion of food contaminated by pathogenic bacteria or their toxins. Bacterial food poisoning is the most common type of food poisoning.

Bacterial food poisoning can be divided into infectious type and toxin type. Any food poisoning caused by eating a large number of pathogenic bacteria is infectious food poisoning; Poisoning caused by eating food that produces toxins due to the proliferation of bacteria is toxic food poisoning.

2. The characteristics of bacterial food poisoning are obvious seasonality, especially in summer and autumn.

2. Animal food is the main food poisoning caused by bacterial food poisoning.

3. The incidence rate is high, and the mortality rate varies according to the poisoning pathogen.

2. Salmonella food poisoning

pathogen and epidemiology

Salmonella is the pathogen that causes Salmonella food poisoning. There are many kinds of Salmonella, and there are more than 2,311 serotypes so far.

Salmonella is G- bacteria, and the optimum temperature for growth and reproduction is 21 ~ 37℃. They can survive for 2 ~ 3 weeks in ordinary water and 1 ~ 2 months in feces and ice water. Both humans and animals can carry bacteria. The main pollution sources are human and animal intestinal excreta. Normal human intestinal bacteria are below 1%, and meat producers can carry more than 11%.

Salmonella food poisoning can occur all year round, but it is more common in summer and autumn from June to September. The food that causes poisoning is mainly animal food, such as all kinds of meat, eggs, poultry, aquatic products and milk, etc. Among them, meat is the most common food. Its carrier rate is much higher than other foods.

The excrement of people and animals infected with Salmonella or their carriers can directly pollute food, which is the main reason for food pollution.

Salmonella food poisoning is mostly caused by food being contaminated by Salmonella and multiplying in large quantities under suitable conditions, and heating treatment is not thorough in food processing, which does not kill bacteria; Or the sterilized cooked food is polluted and grows again, and it is not heated or heated thoroughly before eating.

Salmonella food poisoning is a toxic disease mainly caused by acute gastroenteritis and other symptoms due to a large number of live bacteria entering the digestive tract, attaching to the intestinal mucosa and releasing endotoxin. The general course of disease is 3-5 days, and the prognosis is good. Serious cases, especially children, the elderly and the sick can lead to death if they are not treated in time.

Preventive measures.

(2) control reproduction;

(3) Kill pathogenic bacteria.

Third, pathogenic E.coli food poisoning

1, pathogen and epidemiology

E.coli is G- Brevibacterium, which mainly exists in human and animal intestines and distributes in nature with feces. E.coli has strong vitality in nature, and can survive for several months in soil and water. Ordinary E.coli is a normal bacterium in the intestine, which is not only harmless, but also can synthesize vitamin B. The Escherichia coli produced by it can inhibit the propagation of some pathogenic microorganisms in the intestinal tract. Pathogenic Escherichia coli in the genus Escherichia can cause food poisoning when the human body's resistance is reduced, or when a large number of food contaminated by live pathogenic Escherichia coli is eaten. < P > Pathogenic Escherichia coli exists in the intestinal tract of human and livestock, polluting water, soil, hands of carriers with feces. Contaminated tableware can contaminate or cross-contaminate food. Contaminated food is mostly animal food, such as meat, milk, etc. It can also contaminate juice, vegetables and bread. This disease can occur all year round, and it is more common in May-October.

2. Preventive measures < P > First of all, it is necessary to prevent food from being contaminated by pathogenic Escherichia coli. It is necessary to strengthen meat quarantine, control pollution in production links, and strengthen health examination for employees. Reduce the probability of food contamination. In cooking, it is especially necessary to prevent cooked meat products from being cross-contaminated by raw meat, containers and tools, and the contaminated food must be killed before pathogenic Escherichia coli produces toxin.

Fourth, staphylococcal enterotoxin food poisoning

1, pathogen and epidemiology

Staphylococcus is G+ cocci, which is widely distributed in human and animal skin, nasopharynx cavity, under nails and nature. This bacterium has strong resistance to the external environment. It can survive for several days in a dry state, and it takes one hour to kill the pathogenic bacteria by heating at 71℃. There are two typical strains of Staphylococcus, Staphylococcus aureus and Staphylococcus epidermidis, among which Staphylococcus aureus has the strongest pathogenic effect, which can cause suppurative lesions and septicemia, pollute food and produce enterotoxin, resulting in food poisoning.

Staphylococcus is widely distributed, but its sources of infection are people and animals. Generally, 31% ~ 51% of people have this bacterium in their nasopharyngeal cavity. Patients infected with Staphylococcus aureus have a carrier rate of more than 81% in their nasal cavity and 14% ~ 44% in their hands. Dairy cows with suppurative lesions have a very high carrier rate in their milk. The food that causes poisoning is mainly leftovers, cakes, cream cakes, milk and its products, fish and shrimp, and cooked meat products. Grapes. It can also occur in other seasons.

After food is contaminated by Staphylococcus aureus, bacteria multiply rapidly under suitable conditions, and a large number of enterotoxins are produced. The duration of toxin production is related to temperature and food types. Generally, it takes 1.2 hours at 37℃ or 3 days at 18℃ to produce enough toxic enterotoxins to cause food poisoning. In the presence of sugar, protein and water in 21% ~ 31% CO2 environment, It is beneficial to the production of enterotoxin. Enterotoxin has strong heat resistance, and food with enterotoxin can only be destroyed after boiling for 1.21 minutes, so it can not be completely destroyed in general cooking and heating. Once staphylococcal enterotoxin exists in food, food poisoning is easy to occur.

2, Preventive measures:

Prevention of staphylococcal enterotoxin food poisoning includes two aspects: prevention of pollution and prevention of enterotoxin formation:

(1) Prevention of staphylococcal contamination of food: In order to prevent food processors, catering employees and nurses from being contaminated by bacteria, it is necessary to have regular health checks. People infected with upper respiratory tract should change their jobs, and strengthen the hygienic quality management of food such as eggs and milk of livestock and poultry.

⑵ Prevent the formation of enterotoxin: Food should be stored at low temperature and well ventilated, which can not only prevent the growth of bacteria but also prevent the formation of enterotoxin. Food should be refrigerated and thoroughly heated before eating.

5. Food poisoning by Vibrio parahaemolyticus

1. Pathogen and epidemiology

Vibrio parahaemolyticus food poisoning is the most common food poisoning in the coastal areas of China in summer and autumn. Vibrio parahaemolyticus is G- halophilic, which can grow very well at 37℃ with a salt content of 3% ~ 3.5%. It is sensitive to heat and can be killed by heating at 56℃ for 1 minutes. It is also sensitive to acid and can die immediately in vinegar.

Vibrio parahaemolyticus. Westbank > among marine products such as seabed sediments, fish and shellfish, food poisoning caused by this bacterium is very seasonal, and most of them occur in summer and autumn. The foods that cause poisoning are mainly marine food and salted food, such as marine fish, shrimp, crab, shellfish, bacon, poultry, eggs, pickles or cold dishes, etc. According to the report, the average carrier rate of marine fish and shrimp is 45-49%, and it is over 91% in summer. Fishermen, catering workers and healthy people in coastal areas all have a certain carrier rate, and the carrier rate with a history of intestinal tract can reach 32-35%. The carrier population can pollute all kinds of foods. Food containers, chopping boards, kitchen knives and other food processing tools are cooked at different times, which often leads to cross-contamination between raw and cooked foods. < P > Foods contaminated by Vibrio parahaemolyticus should be stored at a higher temperature, not heated or heated completely before eating, or cooked. Or cross-contamination of raw and cooked food, Vibrio parahaemolyticus enters the human intestine with contaminated food and grows and reproduces, and when it reaches a certain amount, it will cause food poisoning.

2. Preventive measures < P > Measures to prevent food poisoning by Vibrio parahaemolyticus can be taken in many ways. Preserving seafood and other foods at low temperature is an effective method. When cooking and processing all kinds of seafood, the raw materials should be clean and cooked thoroughly. Preventing pollution, controlling growth and reproduction and killing bacteria can effectively prevent this kind of food poisoning.