Lactic acid bacteria refers to a kind of gram-positive bacteria without spores, and the main product of its fermented sugar is lactic acid.

All bacteria that can produce lactic acid bacteria by glucose or lactose fermentation are collectively called lactic acid bacteria. This is a complex group of bacteria, which can be divided into at least 18 genera and more than 200 species. Except for a few, most of them are indispensable flora with important physiological functions in the human body and widely exist in the human intestine. At present, it has been confirmed by biologists at home and abroad that intestinal lactic acid bacteria have a very close direct relationship with health and longevity.

Lactic acid bacteria is a kind of probiotics existing in human body. Lactic acid bacteria can ferment carbohydrates into lactic acid, hence the name. Probiotics can help digestion and contribute to human intestinal health, so they are often regarded as healthy foods and added to yogurt.

There are hundreds of kinds of bacteria living in the human intestine, with the number exceeding one billion. Among them, probiotics are beneficial to human health, represented by lactic acid bacteria and Bifidobacterium. Harmful bacteria are called harmful bacteria, such as Bacillus megaterium and Clostridium perfringens. Probiotics are a huge flora, and harmful bacteria are also a small flora. When probiotics are dominant (accounting for more than 80% of the total), the human body remains healthy, otherwise it is in a sub-health or unhealthy state. Long-term scientific research results show that probiotics represented by lactic acid bacteria are essential beneficial bacteria with important physiological functions. Their number directly affects people's health and life span. The long-term research results of scientists have proved that lactic acid bacteria are very important to people's health and longevity.

However, the number of lactic acid bacteria in human intestine will gradually decrease with the increase of human age. When people are old or sick, the number of lactic acid bacteria may decrease by 100 to 1000 times until the old people die completely. Usually, healthy people are 50 times more than patients, and long-lived old people are 60 times more than ordinary old people. Therefore, the actual situation of the number of lactic acid bacteria in human body has become an important indicator to test whether people are healthy and live longer. At present, due to the wide application of broad-spectrum and powerful antibiotics, probiotics, mainly lactic acid bacteria, in human intestines have been seriously damaged, and their resistance has gradually decreased, leading to more and more diseases and posing a great threat to health. Therefore, it is very important to intentionally increase the number of lactic acid bacteria in human intestine. At present, internationally recognized lactic acid bacteria are considered as the safest strains and the most representative intestinal probiotics. The more probiotics represented by lactic acid bacteria in human intestine, the better. It is also completely in line with the conclusion drawn in the "longevity theory" of Nobel Prize-winning biologist Mechnikov, that is, lactic acid bacteria = probiotics = longevity bacteria.

Faced with the increasingly powerless situation of antibiotics, human beings are constantly seeking new and more effective biological antibacterial products. Developed countries in the world first recognized and initiated the immunotherapy revolution represented by the use of lactic acid bacteria. Swedish scientists have published the results that drinking lactic acid bacteria directly is better than using antibiotics in the treatment of stomach and large intestine inflammation, and the risk is almost zero. In Japan, lactic acid bacteria products have accounted for more than 85% of the Japanese dairy market. In the past 20 years, the average height of Japanese youth has increased by 1.5 cm, and the average life expectancy of the population has reached 85 years, ranking first in the world. This is the direct health effect of lactic acid bacteria products.

Classification status

Field: the field of bacteria

Door: thick-walled door, thick-walled door

Category: Bacillus

Objective: Lactobacillus order.

Family: Lactobacillus.

Genus: Lactobacillus

Beijerinck 190 1

type species

Lactobacillus delbrueckii

(Lechmann 1896) Beijerinck 190 1

type

Lactic acid bacteria can be roughly divided into two categories. One is animal lactic acid bacteria, and the other is plant lactic acid bacteria. Because the animal source comes from animals, because the strain is often in a relatively unstable state, its biological efficacy is also unstable, and it is easy to cause human and animal protein allergy when eaten in large quantities, that is, rejection reaction. Plant-derived lactic acid bacteria are easily recognized by human body, and no matter how much they are ingested, human body will not produce foreign protein rejection. Moreover, plant-derived lactic acid bacteria are more energetic than animal-derived lactic acid bacteria, and the number of them that can reach human small intestine is 8 times that of animal-derived lactic acid bacteria, thus exerting their powerful and stable biological effects.

In fact, ordinary lactic acid bacteria have extremely weak vitality and can only survive in a relatively limited environment. Once they leave these environments, they will also be destroyed. Only specially treated lactic acid bacteria can reach the intestine. Lactic acid bacteria entering the intestine must be large in number and strong in vitality in order to play its biological role. How to develop lactic acid bacteria with high concentration and strong vitality has become the dream pursued by microbiologists today.

Study history

As early as the early 20th century, the famous Russian biologist Mechnikov (1845- 19 16) clearly pointed out in his Nobel Prize-winning "On Longevity" that Bulgarian Balkan residents often drink yogurt in their daily lives, and yogurt contains a large number of lactic acid bacteria, which can effectively colonize the human body. This epoch-making "longevity theory" initiated a new era in which human beings used lactic acid bacteria to produce healthy food. Nowadays, the health food produced by lactic acid bacteria has become a health food of worldwide concern.

As early as 5000 years ago, people have been using lactic acid bacteria. So far, kimchi, yogurt, soy sauce, lobster sauce, etc. What people eat every day is the metabolites of primitive simple random natural fermentation by lactic acid bacteria.

type

Colonies are very small and grow slowly on solid medium.

sports

Most people don't exercise, and a few exercise with their hair.

form

Bacteria are often arranged in chains. Streptococcus lactis, the bacteria are spherical, usually in pairs or chains. Lactobacillus family, rod-shaped, single-chain or chain-shaped, sometimes filamentous, producing false branches.

Useful and harmful

Most of them are isoenzymes, such as streptococcus, which is an important flora closely related to human beings, and some bacteria are pathogenic bacteria of human beings and warm-blooded animals; Some are normal flora in human oral cavity and intestine; Some bacteria are commonly used in dairy products and plant fermented foods, and also in food industry, such as Streptococcus lactis. A few strains are heterotypic fermentation, such as Leuconostoc mesenteroides, which is an important strain for producing dextran (that is, plasma substitute) in pharmaceutical industry, but it is also a harmful bacteria in sugar industry, which often makes sugar juice sticky and cannot be processed.

Most of them are commonly used strains in industry, especially in food industry. It exists in dairy products, fermented plant foods such as pickles, sauerkraut, silage and human intestines, especially in infants.

Thermofermentative bacteria are usually used in the industrial production of lactic acid. For example, the optimum growth temperature of Lactobacillus delbrueckii is 45℃, which is widely used in lactic acid production (such as making aged vinegar and yogurt). ) and calcium lactate manufacturing.

Ten physiological functions of lactic acid bacteria

1, prevention and treatment of lactose intolerance (symptoms such as bloating and diarrhea after drinking fresh milk) common to colored people.

2. Promote the absorption of protein, monosaccharide, calcium, magnesium and other nutrients, and produce a large number of beneficial substances such as vitamin B group.

3. Make beneficial changes in the composition of intestinal flora, improve the function of human gastrointestinal tract, restore the balance of intestinal flora, form an antibacterial biological barrier and maintain human health.

4. Inhibit the reproduction of spoilage bacteria, digest toxins produced by spoilage bacteria, and remove intestinal garbage.

5. Inhibit cholesterol absorption, reduce blood lipid and blood pressure.

6, immune regulation, enhance human immunity and resistance.

7. Anti-tumor and anti-cancer effects.

8, improve SOD activity, eliminate human free radicals, and have the effects of anti-aging and prolonging life.

9. Effectively prevent female genitourinary system bacterial infection.

10, which can control the level of human endotoxin, protect the liver and enhance the detoxification function of the liver.