What are the causes of microorganisms in food?

a The weather is hot and the water in the food evaporates too quickly.

b Long light time, dry air.

c The temperature is high, the bacteria and fungi in the food grow and multiply quickly, the temperature difference between day and night is large, and the organic matter in the food is decomposed slowly.

Selection c Due to a variety of bacteria, molds and other microorganisms, contact with food, and the use of organic matter in food, growth and mass multiplication during the production of a lot of growth metabolites, produce a variety of tastes, such as acid, odor, etc. Therefore, food spoilage is caused by the growth and mass reproduction of microorganisms The life of microorganisms needs suitable temperature, moisture, nutrients, etc., the temperature is higher in summer, the reproduction of bacteria and fungi in food is accelerated, and the number of bacteria and fungi in food increases and multiplies greatly, In turn, the organic matter in the food is decomposed, resulting in the spoilage of the food.

1. Raw materials are brought in, and the intermediate or terminal sterilization is incomplete.

2. The production process is brought in. Air, environment, equipment, processing aids, etc. can all introduce microorganisms into food.

3. Bring in the packaging.

4. Product transportation and sales process brought in. Especially on-site production and bulk food.

Food contains sugars, proteins, and other carbon sources and nitrogen sources suitable for microbial growth, which itself is a natural medium suitable for microbial reproduction.

Once the bacteria are brought into the food, they will multiply rapidly at the right temperature, and the way they are brought in, the utensils, the personnel, the air, the water and other factors.

1. Bacterial hazards.

Bacterial hazards refer to biological hazards produced by bacteria and their toxins. According to their morphology, bacteria are divided into cocci, bacilli, and spirobacteria; According to their pathogenicity, bacteria can be divided into pathogenic bacteria, conditional pathogens and non-pathogenic bacteria. Causes food spoilage.

Causes foodborne illness. If food is contaminated with pathogenic bacteria, it will cause serious food safety problems.

2. Viral hazards.

The virus is so tiny that it is not only invisible to the naked eye, but also invisible under an optical microscope, and requires an electron microscope to detect it. Contamination of food by viruses is not as common as bacteria, but when contamination occurs, the consequences can be severe. Viruses are usually transmitted to food through excreta directly or indirectly.

Food processors carrying the virus can cause direct contamination of food, while sewage often leads to indirect contamination of food. Common viruses in food are hepatitis virus, norovirus, and some viruses related to enteritis.

3. Parasite hazards.

Parasites are a class of organisms that obtain nutrients exclusively from the inside of the host. In the parasitic relationship, the intermediate host of the parasite is of great importance for food safety. Livestock, poultry and aquatic products are the intermediate hosts of many parasites, and consumers may be infected with parasites after eating livestock, poultry and aquatic products containing parasites.

4. Fungal hazards.

The fungal hazards in food mainly include fungi and their toxins, and the harm caused by poisonous mushrooms to food. Mold can damage the quality of food, and some produce toxins, causing serious food safety problems. For example, aflatoxin, variegated aspergillin, ochratoxin can cause liver damage and have a strong pathogenic effect.

Unlike bacterial toxins, mycotoxins can tolerate high temperatures.

The main types of food spoilage are as follows.

1. Stickiness: The stickiness of spoiled food is mainly caused by the polysaccharides formed by bacterial growth and metabolism, which often occurs in carbohydrate-based foods. Common microorganisms that make food religion are:

Alkalogenic bacillus mucous, alcagenesoid, colorless bacillus, aerobacterium, Lactobacillus, Leuconostoc, etc., a few yeasts can also make food spoilage and sticky.

2. Souring: Souring of food often occurs in carbohydrate-based foods and dairy products. The acidification of food is mainly caused by the growth and metabolism of spoilage microorganisms, acetic acid, propionic acid, pseudomonomycetes, micrococcus, streptococcus lactis and lactobacillus standby bacteria, etc.; A small number of molds, such as Rhizopus, also use carbohydrates to produce drums, which can cause food spoilage.

3. Stinkiness: Food odor is mainly caused by the decomposition of protein-based foods by bacteria to produce organic amines, ammonia, sulfur intoxication and fecal olination. Common proteins that break down proteins are: Clostridium spp., Proteus spp., Bacillus spp., etc.

With the continuous improvement of people's living standards, people are paying more and more attention to food safety issues. Food safety is an important livelihood issue, and solving food safety problems plays an important role in ensuring the life and health of Chinese people. Microorganisms mainly refer to various bacterial bodies and pathogenic organisms parasitic in the environment, once the food is "possessed" by microorganisms, it will cause changes in the nature of food, such as mildew, genetic changes, etc., which seriously threatens people's health.

1. The threat of microorganisms to food safety.

a) What is a microorganism.

Microorganisms refer to organisms that are difficult to distinguish with the human eye, such as fungi, bacteria, pathogens and mycoplasma, etc., and some of these microbial groups are beneficial to humans, but some microorganisms are pathogenic viruses or bacteria, which seriously threaten human health. The food production process includes many processes, from raw materials to processing, transportation, preservation, etc., each link is susceptible to microbial contamination. If raw materials are not stored properly, they are susceptible to microbial contamination, which can lead to mildew; In addition, the processing process does not pay attention to hygiene, and the packaging does not pay attention to hygiene, which will also cause microbial pollution; There is also transportation and preservation, which all require good conditions to ensure that the food is not contaminated by microorganisms.

Food contamination caused by microorganisms, such as E. coli contamination, Salmonella contamination, etc., is more common. For example, if food is not strictly sterilized, it will produce botulinum toxin, which will produce a large number of toxins under anaerobic conditions, endangering food safety. Although there are some ways to inhibit its growth during processing, when the temperature rises, Clostridium botulinum will grow again, producing toxins, and these foods are a safety hazard.

Therefore, in daily life, we should pay attention to the shelf life of food, and expired food should not be eaten to avoid foodborne diseases.

2) The impact of microorganisms on food safety.

Microorganisms are the main factors leading to food contamination, which have a certain impact and harm to food safety, which is reflected as follows: Microbial infections occur in food due to the production environment, such as Escherichia coli, Salmonella, etc.; Food will be spoiled and spoiled by environmental influences during transportation and storage, such as poisoning of consumers caused by moldy food; Microorganisms have low environmental conditions, and some manufacturers have reduced costs and operated in violation of regulations in order to seek personal gains, resulting in microbial contamination of food. Microorganisms will multiply and grow under suitable conditions, and it can be seen that changes in environmental conditions have an important impact on the growth of microorganisms.

When the conditions are not suitable, microorganisms cannot grow. However, when the environmental conditions change, such as the packaging bag is broken and the temperature rises, suitable for the growth of microorganisms, the microorganisms will multiply, resulting in food spoilage; When the pH is high or low, the microorganisms will die, and when the pH is right, the microorganisms will also grow in large numbers; When the moisture content is large, it is easy to cause microbial growth, and the probability of microbial contamination in a dry environment is low.

As a kind of organism that exists in nature, microorganisms have a close relationship with the food we depend on for survival. Microorganisms play a vital role in the production of many foods, but they are also the culprits that cause food spoilage, so it is necessary to properly handle the relationship between microorganisms and food. Conditions for spoilage of food caused by microorganisms:

1.Food itself is rich in nutrients, and various proteins, fats, carbohydrates, vitamins and inorganic salts are present, but the proportions are different. If there is a certain amount of moisture and temperature, it is very suitable for the growth and reproduction of microorganisms.

2.The temperature of the environment in which the food is exposed. When the environment is low, it will significantly inhibit the growth and metabolic rate of microorganisms, thus slowing down the spoilage caused by microorganisms.

When food is exposed to high temperatures, if the temperature exceeds the high tolerance limit of microorganisms, the microorganisms die quickly. If the temperature is below the suitable growth temperature, the growth of microorganisms will accelerate with the increase of temperature, and the spoilage of food will be accelerated. 3.

The humidity of the environment in which the food is placed. High humidity, on the one hand, is conducive to the growth and reproduction of microorganisms; On the other hand, it is conducive to the life activities of microorganisms, and will not cause the cell body to lose water and shrink due to too little humidity.

There are 3 main categories of food microorganisms. : Through its role, it can produce a variety of beverages, wine, vinegar, soy sauce, monosodium glutamate, steamed bread and other fermented foods.

It is a microorganism that causes food spoilage. ③：

Also known as foodborne pathogenic microorganisms. It includes pathogenic microorganisms that can cause food poisoning in people and infect humans, animals and plants and cause infectious diseases.

The first food was spoiled, it had a bad taste, it was hard to eat, and there were all kinds of unpleasant tastes. The second is that the microorganisms are eaten in the stomach, and then enter our stomach, and the microbial balance in the body is broken, and it is very uncomfortable to have diarrhea. The third is quite serious, food poisoning caused by microorganisms, this has to go to the hospital**, otherwise it is life-threatening.

Artificial meat. Artificial fish, artificial flour, yogurt, cheese, liquor, kimchi, liquor, etc.

1. The protein produced by single-celled microorganisms can be used to make artificial meat, artificial fish, artificial flour and other foods.

2. Fermented foods have unique flavors that enrich our dietary life, such as yogurt, cheese, wine, kimchi, soy sauce, and vinegar.

Tempeh, milk curd, rice wine, beer, wine, and even stinky tofu.

and stinky winter melon. <>

Use beneficial microorganisms to manufacture and preserve food, control the growth, reproduction and metabolism of spoilage microorganisms, and prevent food deterioration.

The relationship between microorganisms and food is mainly beneficial and harmful, and beneficial and harmful are transformed into each other. Beneficial is divided into direct benefit and indirect benefit, and can be further divided into benefit to human health and beneficial to production; For microorganisms that are harmful to food, some microorganisms are pathogenic bacteria and pathogenic bacteria, which can cause food contamination, and some are because these microorganisms are not harmful, but their metabolites are toxic and endanger human health; There are also microorganisms that do not cause disease on their own and do not produce harmful metabolites. However, its growth and reproduction will have some impact on production.

Some microorganisms have less impact on production and health, while others are good for production and health in some cases, but not good for production and harmful to health in others.

For example, yeast has a very close relationship with people's lives, and working people have used yeast to make many nutritious and delicious foods and beverages for thousands of years. At present, yeast occupies an extremely important position in the food industry.

There are many types of food produced using yeast, such as bread and cakes.

The discovery of microorganisms has had a huge impact on people's lives, especially the development of the food industry. The discovery and continuous development of microorganisms not only promote the progress of the food industry, but also lead to the improvement of people's living standards. With the continuous development of various fields such as cytology, molecular science, microbiology, and instrumentation, the research on microorganisms has also made great progress.

Due to the introduction of microorganisms, the food industry has also broken through traditional food, and on the basis of traditional food, it has created a variety of new foods, expanding people's food choices. However, there are two sides to everything, and while microorganisms bring huge market value to the food industry, they also have certain risks and hazards.

Summary. It is one of the important indicators to measure the quality of food hygiene, and it is also one of the scientific bases for judging whether the inspected food can be eaten Secondly, through the food microbial test, the food processing environment and food hygiene can be judged, and the degree of bacterial contamination of food can be correctly evaluated, providing a scientific basis for various health management work, and providing prevention and control measures for infectious diseases and food poisoning of humans and animals. Thirdly, food microbiological testing is based on the implementation of the "prevention first" health policy, which can effectively reduce the occurrence of food poisoning and zoonotic diseases and protect people's health; At the same time, it is of great political and economic significance to improve product quality, avoid economic losses, and ensure exports.

It is one of the important indicators to measure the quality of food hygiene, and it is also one of the scientific bases for judging whether the inspected food can be eaten Secondly, through the food microbial test, the food processing environment and food hygiene can be judged, and the degree of bacterial contamination of food can be correctly evaluated, providing a scientific basis for various health management work, and providing prevention and control measures for infectious diseases and food poisoning of humans and animals. Thirdly, food microbiological testing is based on the health policy of "prevention first", which can effectively reduce the occurrence of food poisoning and zoonotic diseases and protect people's health. At the same time, it is of great political and economic significance to improve product quality, avoid economic losses, and ensure export and other aspects of lead matching.

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