M-isolation of lactic acid bacteria and preparation of yogurt _ Chi baby

Category: MicrobiologyE. microbiological experimental isolation of lactic acid bacteria and yogurt preparation of health -care skim milk Bifidobacteria culture Bulgaria talk 1. Overview 1.1 yoghurt yogurt is made of fresh milk. Join the fresh milk fermented by lactic acid bacteria and casein and milk acids work, solidifying as creamy white bean curd brain clots. Compare with fresh milk, yogurt, not only has all the nutrients of fresh milk, but also increase over the fresh milk following nutritional characteristics: enhance digestion and appetite. Fresh milk lactose into lactic acid by lactic acid bacteria.����Lactic acid bacteria in yoghurt can stimulate the human digestive gland secretion of digestive juices, increases gastric acid, which can enhance human digestion and appetite. Producing antimicrobial substances, health effects.����Lactic acid bacteria in yoghurt can not only make weakly alkaline substances in the intestines into a weakly acidic substance, as well as antibacterial substance produced, inhibiting reproduction of putrefactive bacteria in the intestines and activities, thereby reducing the gastrointestinal tract of hazardous substances, effects on human health. Enables easier digestion and absorption of proteins and calcium. Yogurt protein to form tiny milk, and fresh milk compared to more easily digested Peck collection.����Lactic acid and calcium lactate calcium binding generated, but also easier digestion and absorption of calcium than fresh milk. The vitamin c content increased. Fresh milk contains small amounts of vitamin c, milk when heating a small amount of vitamin c that are destroyed.����When making yogurt, some lactic acid bacteria to synthetic vitamin c, vitamin c content increased. Lowers cholesterol. Choline content higher in the yogurt, yogurt after, choline who have reduced the role of cholesterol in blood. ���⣬�������о���Ϊ�����������̻��з������á� Due to the yoghurt with the above characteristics, coupled with the yogurt itself smell of fragrant, sweet and delicious, very fond of food, known as "long life food". in addition to nutrient-rich yogurt also contains lactic acid bacteria, so have health effects. These are: 1. maintain intestinal microflora balance, forming biological barriers inhibit harmful bacteria to the gut of the intrusion. 2.ͨ���������Ķ���֬����ٽ���䶯�����������ı���͸ѹ���ֹ���ء� 3. yogurt containing multiple enzymes, promote digestion and absorption. 4. growth inhibition of saprophytic bacteria in the gut, inhibition of toxin produced by the corruption, and brains from hazards of these toxins in the liver to prevent aging. 5. growth inhibition of certain bacteria and saprophytic bacteria in the gut. And thus inhibits these bacteria produce carcinogenic factor, achieve the purpose of preventing cancer. 6. improve the body's immune function, can enhance immune function of substance produced by lactic acid bacteria, you can improve the body's immune to prevent disease. 1.2 species, morphological, physiological and biochemical characteristics of lactic acid bacteria of lactic acid bacteria ferment sugars a class of non-primary products of lactic acid, Gram staining positive bacteria called Bacillus. Most do not campaign, a few lymphatic capillaries movement. Bacteria often arranged in a chain. Only in its products known as lactic fermentation of lactic acid, removing lactic acid products there were more of acetic acid, ethanol, CO2 and other substances known as special lactic acid fermentation. Micro-aerobic bacteria and obligate anaerobic bacterium. Based on cell shape or shaped, can be divided into two broad categories, namely, nisin (Streptococceae) and Lactobacillus family (Lactobacilleae). nisin, mycelium of spherical, usually in pairs or in chains, smaller colonies on a solid culture medium, slow growth. Mostly with fermented such as Streptococcus (Streptococcus), was an important flora closely related to humans, and some bacteria are human beings and warm-blooded animal pathogens and some are normal flora of the human body exists in the mouth and intestines; some are common bacteria in fermented foods of plant and dairy products, often used in the food industry, such as Streptococcus lactis (S.lactis). A small number of special fermentation, of leuconostoc mesenteroides (Leuconostocmesenteroides ) is a production of dextran on the pharmaceutical industry (that is, plasma substitute) important strains, but also a harmful bacteria of the sugar industry, often cannot make sticky sugar juice processing. Lactobacilli, bacteria-shaped, single or chain, sometimes filamentous and false branches.> According to their use of glucose after the products are different, abnormal fermentation of fermentation group is divided into the same type and group. Most kinds of lactose fermentation, without the use of lactic acid, and after fermentation can be under the pH below 6. In this family of Lactobacillus (Lactobacillus) are most important, most especially in food industry is the industry standard strains. Exist in dairy products, fermented plant foods such as pickles, sauerkraut, silage, and the human intestinal tract, especially in the intestine of Suckling. Commonly used high-temperature fermentation of lactic acid bacteria in industrial production. Such as Germany's Lactobacilli (L.delbrueckii), and the optimum growth temperature of 45 �� c, this strain on the calcium lactate and lactic acid manufacturing industries widely. contains lactic acid bacteria in yoghurt and yoghurt with lactic acid bacteria and it is the health effect, containing lactic acid bacteria in yoghurt. Currently on the market usually in yogurt containing Bifidobacterium, lactobacillus acidophilus, and Streptococcus thermophilus, and Bulgaria milk of four strains of Lactobacillus. 1��˫��˾�wbr>�����������Ⱥ��Ҫ��������˫��˾� Bifidobacteria to promote, maintain and improve immunity, delaying the development of the human body plays an important role in aging. Nearly a hundred years of research prove advantages of human intestinal Bifidobacteria microflora. Body in the process of growing up, due to disease, aging and other reasons, Bifidobacterium in vivo on both the quantity and total bacteria share gradually declined. Accordingly, it is number of Bifidobacteria in the body as a sign of a healthy one. Neonatal intestinal Bifidobacterium 92% per cent of total bacterial count, which decrease with age, to disappear completely before dying in the elderly. Bifidobacterium is consumed at any time during the growth process, growth reaches a certain balance at any time, but when people enter the middle-aged and elderly, their self-regulation capacities weakened, proper extrinsic replenishment, maintain and promote health has a positive sense. Currently has a variety of health food that contain Bifidobacterium, also has its advantages, but production costs compared to high and live to preserve a certain degree of difficulty. Popular on the market today added a food or beverage can promote the growth of bifidobacteria oligosaccharides, after ingestion can stimulate intestinal Bifidobacterium in the original reproduction and growth, to achieve the same purpose. Bifidobacterium has the following effect: 1, maintain intestinal normal bacterial flora balance, inhibit the growth of pathogenic bacteria to prevent constipation, diarrhea and stomach disorders; 2, anti-tumor; 3, synthetic vitamins, amino acids in the intestines and improve the absorption of calcium by the body; 4, lower blood cholesterol levels, prevention and treatment of hypertension; 5, improve lactose tolerance of dairy products, increase the digestibility; 6, to enhance the body's immune function, prevent the side effects of antibiotics, anti-aging and prolong life. intestinal Bifidobacteria in breastfeeding infants exist many infants and young children has a number of benefits, such as nutrition, immunization, and anti-infective effect. And also has allergies, resistance to tumors, adjust the role of gut function and improve nutrition. On the clinical, Bifidobacteria have adjust bowel function disorders. To prevent diarrhea, reduce constipation, that is, bi-directional adjustment. This regulation can play a preventive and curative effects of various intestinal diseases. nutrition: Bifidobacteria in human enteric fermentation can produce lactic acid and acetic acid, can increase the utilization of calcium, phosphorus, iron, iron and vitamin d absorption. Bifidobacterium ferment lactose-GAL; they are brain brain adenosine lipid components of the system, are closely related to the rapid growth of infant brain. Bifidobacteria produce vitamins B1, B2, B6, B12 and c-l-methionine, valine, l-aspartic acid threonine and essential nutrients, such as the human body, for the human body have important nutritional role that cannot be ignored. Anti-aging effect of Europe, the USA and Japan's micro-ecological surveys have shown that long fecal Bifidobacteria in the quantity and the elderly, youth. Survey of Chinese scientists in Guangxi in Mardan Mamat longevity of elderly also got the same results. Bifidobacteria against aging causes, is because it can inhibit growth of putrefactive bacteria Bifidobacterium, reduction of their metabolic products of ammonia, hydrogen sulfide, indole, skatole and other harmful substances. Bifidobacteria in addition in recent years due to food allergy prevention, Helicobacter pylori gastritis (gastric ulcer) controlAnd the prevention and treatment of ulcerative colitis is of considerable progress. Bifidobacterium is different from generic drugs. Generic drugs are one-way treatment, such as lowering blood pressure, blood lipids, managing the treatment of diarrhea, constipation, which is a one-way street. Preparation is bi-directional adjustment of Bifidobacterium, can both be high come down, may also be low rise up, Bifidobacterium preparations may at the same time treating diarrhea and constipation, bring the body back to normal, which is adjusted. This product is from East China University of national and biochemical research center (Shanghai) the application of modern biotechnology in the successful development of a new generation of professional health care. Modern pace of life, increased pressure, thus various gastrointestinal diseases particularly caused widespread, this product long Bifidobacterium efficacy of highly active ingredients, without adding any preservatives and hormones, is safe and reliable pure ecological production, added more directly beneficial bacteria, adjusting the micro-ecological balance of the human body. 2) Lactobacillus acidophilus 1. attributes belong to the Lactobacillus acidophilus Lactobacillus, Gram positive Bacillus, rod end of the round, size of 0.6~0.9x1.6~6um, to an individual, couple and short chain occurs. G+, no movement without flagella. Found chiefly in the small intestine to release lactic acid, acetic acid and some antibiotics on bacteria work, probiotics, however weak. 2. health effects of intestinal microflora balance adjustment, inhibits proliferation of poor intestinal microorganisms. Lactobacillus acidophilus on pathogenic micro-organisms with a twist effect. Lactobacillus acidophilus avidin secreted substances (effects of acidophilus (acidolin), the effect of Lactobacillus acidophilus (acidophilin), the effects of lactic acid bacteria (1aetocidon)), and antagonistic effect on intestinal pathogens. Lactobacillus acidophilus (Lactobacillusacidophilus, in short a) and Lactobacillus bifidus (Bifidobacterium, b for short) consisting of mixed fermentation agent. Intake of dairy foods containing both live is good for the digestive organs, especially on gastrointestinal functional disorders of infancy and some long-term oral antibacterial effect of gastrointestinal dysfunction caused by patient, edible after fermented milk containing both live, you can quickly make the normal intestinal flora balance, inhibiting putrefactive bacteria proliferation, with good nutrition and health effects. 3.) thermophilus 1. properties of prokaryotic microorganisms Streptococcus bacteria Streptococcus a Streptococcus: facultative anaerobic or micro-aerobic gram positive bacterium, reaction of catalase-negative, the round or oval, in pairs or in a chain, and does not produce spores, not exercising. Streptococcus thermophilus are also a few species of anaerobic. like hot, is used in fermentation, fermentation together with Bifidobacterium, is a better fermentation technology, buy fermented by yoghurt is well kept in refrigerator and taste better, also to avoid deterioration, lengthens the maintaining freshness time. When the fermentation, Streptococcus thermophilus to fermentation and Lactobacillus fermentation, which produces lactic acid during the fermentation process and effects of lactic acid bacteria helps digestion of lactose, to be clean and prevent the growth of harmful bacteria in intestinal function. If only a lactobacillus, it is difficult to ferment. 2. health effects of Streptococcus thermophilus to healthy human intestinal normal bacterial flora, growth, reproduction in the human intestine. Directly complement human normal physiology of bacteria, adjusting the balance of intestinal flora, suppression and clears people of potentially harmful bacteria in the gut. Streptococcus thermophilus and Bulgaria real live Lactobacillus bacteria is milk fermented products on human work and the substrate. These substances entering the body, can promote the proliferation of beneficial bacteria in the body, inhibiting reproduction of bacteria, playing the entire intestine and antibacterial effect. 4.) Bulgaria Lactobacillus Yogurt (yogurt, writing Yoghurt) is the Thracian language the term. Yog means "heavy coagulation" Urt means "milk". According to historical records of THRACIANS at around 3500 BC to live on this land, were established in the 5th century BC the first mined the Andean countries. Yogurt is said to be THRACIANS use a paper-bag of milk in the waist, body temperature so that the multiplication of bacteria and fermented milk produced. ����Ҫ˵ֻ�б������������������̣�������һ�ң�������ꡱ������Ҳ����ȫ�� According to historical records, Mongolian of China as early as before the Han dynasty had mastered milk production techniques, in 641 ad when Tang Princess Wencheng to Tibet, there is "yogurt" records. When I first went to Xinjiang in 1958, Kazakh herders see that they are using Sheepskin pockets isolated from Koumiss. In our parishes, isolated from Koumiss, sour milk, sour milk is commonly found in beverage of life, pastoral yoghurt drink less, but cannot be separated from the acid isolated from Koumiss; isolated from Koumiss are pastoralists VIPs fixture. Cheese is a pastoral grazing carrying everyday "food". Therefore, yogurt and cheese are those of the legend of Genghis Khan Mongolia forces without provisions for one, is the logical thing, no doubt. 2.ʵ�����2.1�����豸��ƽ��ţ�dzס���¯��/>pH��ֽ���̶��´ɱ�����Ͳ��©����©���ܡ����������Թܡ�����wbr>�����wbr>��ܡ�ţƤֽ����������ǩ��500mL׶��ƿ������250mL׶��ƿ�������Թ�20ֻ��500mL�ձ�������250mL�ձ�������100mL�ձ��������ƾ��ơ�ʯ����wbr> �����루������ 2.2ʵ������50L�ĸ�ѹ��������wbr>��ѹ�������wbr>������̨����ѧ��΢����75%�ƾ��ޡ� ���䡣 2.3ʵ��ҩƷ�������̡���֬�̷ۻ�ȫ֬�̷ۡ����ǡ�1.6%��׷����Ҵ���Һ����ĸ�ࡢ��֬���ᾧ��ȾҺ��¬���ϵ�Һ��95%�Ҵ���ʫ̳�Ḵ��ȾҺ�� 3. test methods and procedures 3.1BCG culture medium and sterilization of milk (a) liquid: 10 g of skimmed milk powder, water 50ml, join the ethanol solution of bromocresol green 1ml,80 1.6% 20min �� c sterilization. (B) liquid: yeast extract 1 g, 50 g water, agar and 2 grams of pH6.8,121 2.min �� c sterilization. In accordance with the formula correct access to needed medicines in the beaker, porcelain enamel cups of water you want to join in, the glass rod Homogenizer, heating to dissolve, 1N NaOH or 1NHCl adjust pH, pH test strip control, plus agar dissolves, the heating process to keep stirring, may be appropriate to supply water. In the conical flask of agar dissolves completely into the 250mL, gauze wrapped (be careful not to polluted gauze) with kraft paper packed, labeled (you must write with a pencil), and indicate what kind of medium. In a pressure cooker, 1kg/cm2 under pressure to maintain 30min. 3.2 to BCG medium plate method will destroy good bacteria's liquid a and liquid b chenre fully mixed, light the alcohol to sterilize the air around the light, and with his left hand held flat near the spirit lamp with your thumb and the little finger to open a small gap, chenre medium, such as flat, poured into the media just to cover flat-bottom after DAO Hao flat on the laboratory bench plate, gently shake is a medium for the formation of a plane, such as medium for cooling down after the solidification and labelling. (Note: the entire experiment to do near the spirit lamp, to ensure that the medium is not bacterial) 3.3 tube dispensing and sterilization of skimmed milk direct choice of separated milk or skimmed milk sugar 5 g and 10 g, 95 grams of water (sucrose-water ratio in the range 1:10) preparation, content suitable to tube one-third, 15min 115 �� c sterilization. 3.4 purification of lactic acid bacteria markets sell fresh yogurt intake, respectively, on agar plates with pin access BCG vaccinated cattle culture medium, training 48h 40 �� c, if slightly flat round yellow colonies and the surrounding medium turns yellow tentatively set for lactic acid bacteria. Select typical colony going to skim milk by lactic acid bacteria in test tubes, 40 �� c cultivation 8~24h solidification occurs if milk, no bubbles, acidic, smear cells of rod or hammer, Gram staining positive, you can be ' passage 3 times in a row, finally chose 3~6h coagulation of milk tubes, for strains to be used. 3.5 fermented by lactic fermentation and check: to observe the BCG medium milkAcid bacteria colonies characteristic, choose better growing colonies of bacteria-free operation is lactic acid bacteria by inoculation test tube fitted with skimmed milk, 40~42�� still training. Testing: in order to facilitate the determination of lactic acid fermentation, and skim milk for Gram staining solution in a test tube, microscopic examination. Gram positive, non-Spore for lactic acid bacteria Lactobacillus or Neisseria gonorrhoeae, record test results. 3.6 production of lactic acid bacteria drink skim milk and water at 1:7~10 per cent, while adding 5%~6% of sucrose and fully mixed, in 10~15min 80~85�� sterilization and cooling to 35~40�� as a medium for making beverages quality. Thoroughbred hot lactococcus, Bulgaria equal mixture of Lactobacilli as a starter, to 2%~5% the inoculum for each access in medium quality drink broth, fresh milk can also be sold as a starter. Ring vaccination vaccinated, loading to the sterilization of sour milk in a bottle, shake after inoculation, every bacterium beverages repeated loading 3~5 bottle fermentation broth, then would be conical bottle with gauze, kraft paper wrapped. Bottle on 40~42�� lactic acid after inoculation, training 3~4H in incubators. When observing, if milk stops after the culture. Then turn to 4~5�� at low temperature refrigeration 24h. To taste the quality standard, yoghurt with Lactobacillus and lactococcus equivalent single and mixed fermentation of lactic acid fermentation of lactic acid compared to former aromas and tastes better. Where there are smell when tasting, shows that sour milk contaminated with bacteria. 3.7ʵ�����������ʵ�������ʱ������5��19������ϴ��������������BCGţ������100ml�����ƽ��5��20�����ԭ��ͣ��һ��5��21��������BCGţ������100ml�����ƽ������������߷��롢����֬���Թ�100ml�����װ10֧�Թ�5��22������BCGţ������100ml�����ƽ������ȴ�5��23�����һ��ӵ���֬���Թܡ�����24h(21��ƽ����Ⱦ��ѡ���ƾ��������Ϊ��һ��)�������޾�ˮ��20min��121�棩����׶��ƿ���װ�������̻��߷���5��24������BCGţ������100ml�����ƽ�壨��B��A������֬���Թܵڶ����߷��롢��֬���Թ���������Ⱦɫ����ȴ�5��26������BCGţ������100ml�����ƽ�壨��B��A����������߷��루��������Ⱦ��ʹ��նϹ����Ľ��֣�����ȴ�5��27����������ֵ���֬���Թ�����������BCGţ������100ml�����ƽ�壨��B��A����5��28����27��ƽ��Ⱦ��ʣ��BCGţ����������ƽ�塢����֬���Թ������Ĵ��߷��뼰������Ⱦɫ����ȴ�5��29��������������100ml��ƿ�������ȴ��������Ϊ�˽����Ĵ���ֵ������������������дʵ�鱨��5��30���������̺�����������Ʒ������3.8.ʵ���������ǰ��þ���ձ�ȡ�������г��Ϲ���ģ�������ţ���������̣��ý��ֻ����������̽����Ѿ���õ�BCG����ƽ���У�ע��������Ӧ���޾������²��������Ӻ��ֺ����ϱ�ǩ�������� Culture plate on the rear of the majority were infected with the bacteria, Heteropoly gray and white, as long as the individual flat long pale yellow with lactic acid bacteria colony, and poor growth. first: select the growth of good bacteria by lactic acid bacteria, inoculation needle will access two strains under aseptic conditions in skimmed milk tube, after receiving the good seed with labels on culture. The result: two skim milk tube, a solidified good colours-White slightly yellow, pale yellow clear liquid on the surface, a solidified is not good. Yogurt in the test tubes are Gram staining, is as follows: under the microscope: there are 3 kinds of bacteria, Gram stain purple, Enterococcus, Streptococcus bacteria Lactobacillus and little slender second generation: select solidification good skim milk tubes, inoculating loop under aseptic conditions to access BCG strains in cultured flat, after receiving the good seed with labels on culture. Culture: the colony does not grow well on flat, and there are microbes. Bacteria colony to projecting blisters, gray and white, Gram stain purple, stubby bacilli of Clostridium perfringens. Flat plate having a small amount of lactic acid bacteria, slightly yellow color is white. contamination of flat third-generation: select the growth of good bacteria by lactic acid bacteria, inoculation needle will spawn access the remaining eight under aseptic conditions in skimmed milk tube, after receiving the good seed with labels on culture. Culture: eight skim milk test tube, has six freezing better, slightly yellow color is white, pale yellow clear liquid on the surface, two bad solidification. Yogurt in the test tubes are Gram-stain: solidification of less effective as a wool colours-white, pale yellow clear liquid on the surface. Under the microscope: Gram staining is purple, Bacillus with fine short and stubby, both contents are missing. Freezing effect is extremely well, white, almost no liquid. Under the microscope: Gram staining is purple, containing a large number of slender, big ball of Bacillus bacteria Lactobacillus bacteria and spindle. fourth generation: select solidification good skim milk tubes, inoculating loop under aseptic conditions to access BCG strains in cultured flat, after receiving the good seed posts tagged culture�� Culture: the colony does not grow well on flat, and there are bacteria, bacteria colony to projecting blisters, gray and white, there is no contamination of, grow better colony. growing better colonies make yogurt: select the growth of good bacteria by lactic acid bacteria, inoculating loop under aseptic conditions, gently scrape take BCG strains on the medium, the access of lactic acid bacteria culture medium, after receiving the good seed with labels, bottle on 40~42C lactic acid after inoculation, training 3~4H in incubators. When observing, if milk stops after the culture. Then turn to 4~5C at low temperature refrigeration 24h. sour milk products 4. experimental result and discussion 4.1 experimental results uniform yogurt clots, milky white, delicate, wool, bursting bubble, the surface there is a small amount of whey (branch water liquid), smell of light, with milk. 4.2 considerations for 1 gram staining. smear should not be too thick, and it should be evenly coated, if too sticky will dilute with sterile water, making it able to observe bacterial forms. 2. dyeing process, the solution you want to overwrite the mycelium, flushing it should go to slide on the residual water, dyeing dyeing liquid to be diluted so as not to affect the results, and the water should not be too large to avoid bacteria being washed away. 3. dye decolorization of success is the time, time is too short, Gram negative bacteria is dyed Gram positive bacterium, decolorization of excessive, Gram positive bacteria are also dyed gram negative bacteria. In addition, the duration and smear thick-and alcohol-related. Dye should not be too deep, which is not conducive to observing the morphology of bacteria. 4.3�Ӿ���Ⱦ;����Ԥ��1)���Ӵ�� Main reasons: medium and utensil sterilization is not complete; bacteria contaminated during the moving process, and strains in culture or in the process of preservation of contaminated. 2)������ Due to the limited laboratory conditions, only with spirit lamp for sterilization, sterilization does not thoroughly introduce bacteria that can cause infection. 3)�������豸����׵���Ⱦ�� Main reasons: material traits sterilization; real tank sterilization fails to fully discharge the tank air; medium when continuous sterilization, steam pressure fluctuation, medium sterilization temperature has not been reached, leading to sterilization without thorough and pollution; equipment and pipeline "dead ends". 4)�豸��©����Ⱦ�� Fermentation equipment, piping, valves, long-term use, due to corrosion, abrasion and vibration and other reasons, often result in leakage. 5)����ʧ��ͼ��������Ҳ������Ⱦ�� Such as moving sterilization of inoculation PIN does not complete when printed in bacteria, outside air to enter the infection, improper operation of bacteria introduced when flat, and so on. 4.4 ��������1. why yeast medium yellow around probiotics? answer: because the medium of bromocresol green in the case of acid yellow, lactic acid bacteria produce lactic acid so that it turns yellow and yellow. 2. why solidification good Gram staining the fusiform is considered yeast? answer: because in the Gram stain, microscopic observation of strain shape is oval-shaped and two slightly pointed, larger particles, incompatible with the morphological characteristics of lactic acid bacteria, may contain yeast and lactic acid bacteria, similar to the above observation of morphology of bacteria and yeast, yeast is considered to be. Generally contain yeast yeast well with other fungi, and these bacteria of lactic acid bacteria is what we want. experimental considerations in 4.5 1. When you use BCG medium agar plate screening of lactic acid bacteria in milk, pay attention to pick take the typical characteristics of yellow colonies, combining microscopy observation, enabling efficient isolation of lactic acid bacteria. 2. production of lactic acid bacteria drinks, excellent selection of lactic acid bacteria, lactobacillus and lactococcus equivalent mixed fermentation so that it has a unique flavor and good taste. 3. disinfection of milk should have appropriate temperature and time to prevent using high temperature sterilization for a long time to destroy yogurt flavors. 4. the eligibility criteria should be carried out by the Ministry of health provides detection of health, such as the coliform testing. ByTasting and testing, qualified yogurt at 4 degrees c under the conditions of cold storage, you can save 6~7d. 6. reference 1). Li Yumei, and Liu Derong, microbiology, medicine technology publishing house, China, December 2006), of the microbiology, Chinese Academy of agricultural Publishing House, January 2007) Shen ping, microbiology, and higher education press, May 2003) Zhou Deqing, microbiology, of course, higher education press, 1993) �� of the microbiology and laboratory technology, chemical industry press, August 2007) Shen ping, and fan Xiu-Rong, and Li Guang-Wu, of the microbiology laboratory of the higher education press, June 1999