What are the bacteria susceptible to infection in food? Symptoms and preventive measures of each bacterial poisoning?

First, the concept and characteristics of bacterial food poisoning

concept

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

Bacterial food poisoning can be divided into two types: infectious food poisoning and toxic food poisoning. Poisoning caused by eating food that produces toxins due to bacterial reproduction belongs to toxic food poisoning.

2, the characteristics of bacterial food poisoning

There is obvious seasonality, especially in summer and autumn.

Animal food is the main cause of bacterial food poisoning.

⑶ The incidence rate is high, and the mortality rate varies with the poisoning pathogens.

Secondly, Salmonella is food poisoning.

Pathogen and epidemiology

Salmonella is the pathogen that causes salmonella food poisoning. There are many kinds of Salmonella, so far there are more than 2300 serotypes.

Salmonella is a G- bacterium, and the optimum temperature for its growth and reproduction is 20 ~ 37℃. They can survive for 2 ~ 3 weeks in ordinary water and 65,438+0 ~ 2 months in feces and ice water. Salmonella is widely distributed in the natural environment, and both humans and animals can carry bacteria. The main pollution sources are human and animal intestinal excreta. Normal people's intestinal bacteria are below 1%, and they are meat producers.

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, milk and so on. Among them, meat and eggs are the most vulnerable to salmonella pollution, and their carrying rate is much higher than other foods.

Human and animal feces infected with Salmonella or its carriers can directly pollute food, which is the main cause of food pollution.

Salmonella food poisoning is mostly caused by food contaminated by Salmonella, which multiplies in large quantities under suitable conditions, and the heating treatment in food processing is not thorough, and the bacteria are not killed; Or the sterilized cooked food is polluted and grows again, and the factors such as not heating or not heating thoroughly before eating can all lead to poisoning.

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

preventive measure

(1) to prevent pollution;

(2) birth control;

(3) Kill pathogenic bacteria.

Three, pathogenic Escherichia coli food poisoning

1, pathogens and epidemiology

Escherichia coli is G- Brevibacterium, which mainly exists in human and animal intestines and distributes in nature with feces. Escherichia coli has a strong vitality in nature, and can survive in soil and water for several months. Escherichia coli is a normal intestinal bacteria, which is not only harmless, but also can synthesize vitamin B, K and folic acid for human body. The Escherichia coli produced by it can inhibit the reproduction of some pathogenic microorganisms in the intestine. Pathogenic Escherichia coli in Escherichia coli can be eaten when the human body's resistance decreases.

Pathogenic Escherichia coli exists in human and animal intestines, which can pollute water and soil with feces. Contaminated water, soil, carriers' hands and contaminated tableware will pollute or cross-contaminate food. Contaminated foods are mostly animal foods, such as meat and milk. It will also pollute fruit juice, vegetables and bread. This disease can occur all year round, especially in May ~ 10.

2. Preventive measures

First of all, we should prevent food from being contaminated by pathogenic Escherichia coli. We should start with routine health management such as strengthening meat quarantine, controlling pollution in production links and strengthening health examination of employees to reduce the probability of food pollution. When cooking, it is especially important to prevent cooked meat products from being cross-contaminated by raw meat, containers and tools. The contaminated food must be killed before pathogenic Escherichia coli produces poison.

Fourth, staphylococcal enterotoxin food poisoning.

1, pathogens and epidemiology

Staphylococcus is G+ cocci, which is widely distributed in human and animal skin, nasopharyngeal cavity, under nails and nature. Strong resistance to external environment, can survive for several days in dry state, and can kill pathogenic bacteria by heating at 70℃ for one hour. There are two typical strains of 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, leading to food poisoning.

Staphylococcus is widely distributed, but its source of infection is people and animals. Generally, 30% ~ 50% of people have this kind of bacteria in nasopharyngeal cavity. The carrier rate of Staphylococcus aureus infection in nasal cavity of patients is above 80%, and it can reach 14% ~ 44% in human hands. Dairy cows with purulent lesions have a very high carrying rate in their milk. The food that causes poisoning is leftovers and cold food.

After food is contaminated by Staphylococcus aureus, bacteria multiply rapidly under suitable conditions and produce a large number of enterotoxins. The duration of toxin production is related to temperature and food type. It usually takes 37℃ 12 hours or three days 18℃ to produce enough toxic enterotoxin to cause food poisoning. When sugar, protein and water exist in 20% ~ 30% CO2 environment, it is beneficial to the production of enterotoxin. Enterotoxin has strong heat resistance, and food containing enterotoxin can only be destroyed after boiling for 120 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:

⑴ Prevention of food contamination by staphylococci: In order to prevent all kinds of food from being contaminated by bacteria, food processors, catering employees and nurses must have regular health checks. Those with purulent infection should change jobs. Hygienic quality management of eggs, milk and other foods of livestock and poultry should be strengthened.

⑵ Prevent the formation of enterotoxin: Food should be kept at low temperature and well ventilated, which can prevent the growth of bacteria and the formation of enterotoxin. Food should be refrigerated and heated thoroughly before eating.

Verb (abbreviation of verb) Vibrio parahaemolyticus food poisoning

1, pathogens and epidemiology

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

Vibrio parahaemolyticus widely exists in offshore seawater, seabed sediments, fish and shellfish and other warm seafood. Food poisoning caused by Vibrio parahaemolyticus is seasonal, mostly in summer and autumn. Food poisoning is mainly seafood and pickled food, such as seafood, shrimp, crab, shellfish, bacon, poultry, eggs, pickles or cold dishes. It is reported that the average carrying rate of seafood fish and shrimp is 45-49%.

Vibrio parahaemolyticus in food mainly comes from the pollution of offshore seawater and seabed sediments to seafood and ponds and rivers near the sea area, and also pollutes freshwater products living in this area. Fishermen, catering workers and healthy people in coastal areas all have a certain carrying rate, and the carrying rate with intestinal history can reach 32-35%. Carriers can pollute all kinds of food. Different cooking times of food processing tools such as food containers, chopping boards and kitchen knives often lead to cross-contamination of raw and cooked foods.

When the food contaminated by Vibrio parahaemolyticus is stored at high temperature, it is not heated or heated completely before eating, or the cooked products are contaminated by carriers or the raw and cooked foods are cross-contaminated. Vibrio parahaemolyticus enters human intestine with contaminated food and grows and reproduces. When it reaches a certain amount, it will cause food poisoning.

2. Preventive measures

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. Preventing pollution, controlling growth and reproduction and killing bacteria can effectively prevent such food poisoning.