question: How are living lactic/yogurt cultures not killed during digestion?
comment: Gut flora is a misnomer, as that "flora" inside your digestive tract has no plants. What is meant by gut flora actually are the hordes of symbiotic bacteria that live inside you, and help you brake down foods and digest them. These bacteria are harmless to your body (as long as your stomach isn't ruptured), they can survive the acidity of your stomach juices, and they do in fact die off, break up each other and get digested. They just multiply fast enough to not die out completely. They also protect their turf and fight off other, potentially more dangerous species. The bacteria found in yoghurt are harmless to humans and break down lactose, and therefore are exactly the helpful kind of bacteria you want to live in your gut flora.
passages: While there are several types of "Lactobacillus" that are able to convert sugars into lactic acid and CO, most are unable to survive alcoholic fermentation and will die off in this type of environment. "L. fructivorans" is one of the few species that successfully survives alcoholic fermentation and continues to grow and engage in cell multiplication afterwards.
   Section::::Metabolism.
  
  Many lactobacilli operate using homofermentative metabolism (they produce only lactic acid from sugars), and some species use heterofermentative metabolism (they can produce either alcohol or lactic acid from sugars). They are aerotolerant despite the complete absence of a respiratory chain. This aerotolerance is manganese-dependent and has been explored (and explained) in "Lactobacillus plantarum". Many species of this genus do not require iron for growth and have an extremely high hydrogen peroxide tolerance.
  
  Section::::Genomes.
   Generally, the bacteria used as starter culture are not the same used as probiotics. There are, however, cases when one bacterium can be used both as starter culture and as probiotic. The scientific community is presently trying to deepen understanding of the roles played by microbes in food processing and human health.
  
  The most important bacteria in food manufacturing are "Lactobacillus" species, belonging to the group of lactic acid bacteria.
   The main method of producing yogurt is through the lactic acid fermentation of milk with harmless bacteria. The primary bacteria used are typically "Lactobacillus bulgaricus" and "Streptococcus thermophilus", and United States as well as European law requires all yogurts to contain these two cultures (though others may be added as probiotic cultures). These bacteria produce lactic acid in the milk culture, decreasing its pH and causing it to congeal. The bacteria also produce compounds that give yogurt its distinctive flavor. An additional effect of the lowered pH is the incompatibility of the acidic environment with many other types of harmful bacteria.
   The safety of microbial drug delivery is tied to the microbes’ commensal capability and instance of pathogenesis. A highly pathogenic microbe would not be suitable for medical treatment due to an inherent infection risk. "L. lactis" is considered by the Food and Drug Administration (FDA) to be generally recognized as safe (GRAS), as it is commonly found in widely consumed dairy products, suggesting its safety in medical treatment. "B. ovatus" is naturally found in 10% of healthy human colons, demonstrating safety in its compatibility with the human gut microbiota; however, "Bacteroides" species are known in some cases to cause infections, typically resulting from surgery in the GI tract.
   Section::::Probiotics.
  
  Probiotics are products aimed at delivering living, potentially beneficial, bacterial cells to the gut ecosystem of humans and other animals, whereas prebiotics are indigestible carbohydrates delivered in food to the large bowel to provide fermentable substrates for selected bacteria. Strains of LAB are the most common microbes employed as probiotics. Two principal kinds of probiotic bacteria, members of the genera "Lactobacillus" and "Bifidobacterium", have been studied in detail.
   Yogurt is produced using a culture of "Lactobacillus delbrueckii" subsp. "bulgaricus" and "Streptococcus thermophilus" bacteria. In addition, other lactobacilli and bifidobacteria are sometimes added during or after culturing yogurt. Some countries require yogurt to contain a certain amount of colony-forming units (CFU) of bacteria; in China, for example, the requirement for the number of lactobacillus bacteria is at least 1 million CFU per millilitre.
   In general, strains of " Lactobacillus " have been considered safe because of their association with food and because they are normal inhabitants of the human microflora. They have also been identified to have a low pathogenic potential further reinforcing the idea that they are safe microbes.
   On the other hand, there are certain similarities between "L. bulgaricus" GLB44 and some of the other probiotics. For example, "L. bulgaricus", "L. rhamnosus" GG and "L. plantarum" 299v all have scientific records of their ability to pass successfully through the gastrointestinal tract, Also they all have records to inhibit to a degree pathogenic bacteria.,
   Concerns regarding the containment of recombinant microbes in the gut have been addressed through safety mechanisms in both "L. lactis" and "B. ovatus". Containment refers to the inability of microbes to colonize the external environment, where they may have unknown consequences. LL-Thy12 will die upon removal from the body, as they depend on dietary thymidine for survival. "B. ovatus" is naturally an obligate anaerobe, so any recombinant strain is expected to die in the presence of oxygen once removed from the body.
  
  Section::::See also.
  
  BULLET::::- Gut flora
  
  BULLET::::- Oral administration
  
  BULLET::::- Mucous membrane
  
  BULLET::::- Absorption (pharmacokinetics)
   The National Yogurt Association (NYA) of the United States gives a "Live & Active Cultures Seal" to refrigerated yogurt products that contain 100 million cells per gram, or frozen yogurt products that contain 10 million cells per gram at the time of manufacture. In 2002, the FDA and WHO recommended that "the minimum viable numbers of each probiotic strain at the end of the shelf-life" be reported on labeling, but most companies that give a number report the viable cell count at the date of manufacture, a number that could be much higher than what exists at consumption. Because of the variability in storage conditions and time before eating, exactly how many active culture cells remain at the time of consumption is difficult to determine.
   Both "L. mesenteroides" and "E. faecalis" are predominantly delivered to the batter by the urad dal. Both strains start multiplying while the grains are soaking and continue to do so after grinding.
  
  "L. mesenteroides" tolerates high concentrations of salt unlike most other bacteria. Hence the salt in the batter and the ongoing generation of lactic acid both suppress the growth of other undesirable micro-organisms.
  
  Section::::See also.
  
  BULLET::::- Bánh bò
  
  BULLET::::- Chwee kueh
  
  BULLET::::- Cuisine of Karnataka
  
  BULLET::::- List of Indian breads
  
  BULLET::::- List of steamed foods
  
  BULLET::::- Sanna (dish)
  
  BULLET::::- Serabi
  
  BULLET::::- Rava idli
  
  BULLET::::- White sugar sponge cake
  
  Section::::Bibliography.
   As a result of the fermentation, very little lactose remains in kefir. People with lactose intolerance are able to tolerate kefir, provided the number of live bacteria present in this beverage consumed is high enough (i.e., fermentation has proceeded for adequate time). It has also been shown that fermented milk products have a slower transit time than milk, which may further improve lactose digestion.
  
  Section::::Nutrition.
  
  Section::::Nutrition.:Composition.
   Section::::Food production.
  
  Some "Lactobacillus" species are used as starter cultures in industry for controlled fermentation in the production of wine, yogurt, cheese, sauerkraut, pickles, beer, cider, kimchi, cocoa, kefir, and other fermented foods, as well as animal feeds and the bokashi soil amendment. The antibacterial and antifungal activity of "Lactobacillus" species rely on production of bacteriocins and low molecular weight compounds that inhibits these microorganisms.
   In addition to bacteria, kefir often contains strains of yeast that can metabolize lactose, such as "Kluyveromyces marxianus", "Kluyveromyces lactis", and "Saccharomyces fragilis", as well as strains of yeast that do not metabolize lactose, including "Saccharomyces cerevisiae", "Torulaspora delbrueckii", and "Kazachstania unispora". The nutritional significance of these strains is unknown.
  
  Section::::Production.
   BULLET::::- Yogurt – lactobacilli used in the production of yogurt remove lactose to varying degrees, depending on the type of yogurt. Bacteria found in yogurt produce their own enzyme, lactase, that facilitates digestion in the intestines in lactose intolerant individuals.
  
  BULLET::::- Cheese – fermentation also reduces the lactose content of cheeses and aging reduces it further; traditionally made hard cheeses might contain 10% of the lactose found in an equivalent volume of milk. However, manufactured cheeses may be produced using processes that do not have the same lactose-reducing properties.
   The quest to find food ingredients with valuable bioactive properties has encouraged interest in exopolysaccharides from LAB. Functional food products that offer health and sensory benefits beyond their nutritional composition are becoming progressively more important to the food industry. The sensory benefits of exopolysaccharides are well established, and there is evidence for the health properties that are attributable to exopolysaccharides from LAB. However, there is a wide variation in molecular structures of exopolysaccharides and the complexity of the mechanisms by which physical changes in foods and bioactive effects are elicited.
  
  Section::::Lactic acid bacteria genera.
  
  BULLET::::- "Abiotrophia"
  
  BULLET::::- "Aerococcus"
  
  BULLET::::- "Carnobacterium"
   Lactic acid bacteria are fastidious organisms that cannot synthesize on their own all of their complex nutritional requirements. For LAB to grow and complete malolactic fermentation, the constitution of the wine medium must provide for their nutritional needs. Like wine yeast, LAB require a carbon source for energy metabolism (usually sugar and malic acid), nitrogen source (such as amino acids and purines) for protein synthesis, and various vitamins (such as niacin, riboflavin, and thiamine) and minerals to assist in the synthesis of enzymes and other cellular components.
   Ilya Metchnikoff, a professor at the Pasteur Institute in Paris, researched the relationship between the longevity of Bulgarians and their consumption of yogurt. He had the idea that aging is caused by putrefactive activity, or proteolysis, by microbes that produce toxic substances in the intestine.
   The use of gut microbes as probiotics in food is aimed towards preventing and treating various health problems. Among these health problems allergies, neoplastic growth, and inflammatory bowel disease are included. Recent areas of study have focused on the influence of probiotics on metabolic functions of their host. One area has been the metabolism of cholesterol by LABs acting as probiotics. Research has shown that "Lactobacillus" species have been proven to remove cholesterol in vitro through various ways such as assimilation, binding to the surface cells, and incorporation into cellular membranes.
  
  Section::::Probiotic.:pH and Bile Tolerance.
   When consumed, most bacteria do not survive the acidic conditions of the human stomach. The few surviving bacteria conserve their energy and stored nutrients during the passage through the stomach by shutting down protein production. When the surviving bacteria exit the stomach and reach the small intestine, they must propel themselves through the thick mucus that lines the small intestine to reach the intestinal walls where they can attach and thrive.
   The degree to which proteobiotics can reduce virulence-gene expression depends on the pathogen and the source of the proteobiotics. "Lactobacillus acidophilus"-derived proteobiotics down-regulate virulence genes in enterohemorrhagic "Escherichia coli", "Clostridium difficile"", Salmonella" Typhimurium", Listeria monocytogenes" and "Campylobacter jejuni""." Whereas those produced by "Bifidobacterium" spp. have been shown to impact virulence gene expression in "Campylobacter jejuni", enterohemorrhagic "Escherichia coli", "Clostridium difficile", "Clostridium perfringens", and "Salmonella" Typhimurium"." 
   BULLET::::- "Lactifluus annulatolongisporus" (Maba) Maba 2015
  
  BULLET::::- "Lactifluus austrovolemus" (Hongo) Verbeken 2012
  
  BULLET::::- "Lactifluus burkinabei " Maba 2015
  
  BULLET::::- "Lactifluus guellii " Maba 2015
  
  BULLET::::- "Lactifluus brunneocarpus" (Maba) Maba 2015
  
  BULLET::::- "Lactifluus caperatus" (R.Heim & Gooss.-Font.) Verbeken 2012
  
  BULLET::::- "Lactifluus corbula" (R.Heim & Gooss.-Font.) Verbeken 2011
  
  BULLET::::- "Lactifluus claricolor" (R.Heim) Verbeken 2011
  
  BULLET::::- "Lactifluus fazaoensis" Maba, Yorou & Guelly 2014
  
  BULLET::::- "Lactifluus flavellus" Maba & Guelly 2015
  
  BULLET::::- "Lactifluus longibasidius" Maba & Verbeken 2015
  
  BULLET::::- "Lactifluus membranaceus" (Maba) Maba 2015
  
  BULLET::::- "Lactifluus melleus" Maba 2015
  
  BULLET::::- "Lactifluus pisciodorus" (R.Heim) Verbeken 2012
  
  BULLET::::- "Lactifluus pseudotorminosus" (R.Heim) Verbeken 2011
   Due to more than a century of safe use, the FDA has granted "L. bulgaricus" a "grandfather" status, with an automatic GRAS status (Generally Recognized as Safe). Moreover, the Code of Federal Regulations mandates that in the US, for a product to be called yogurt, it must contain two specific strains of lactic acid bacteria: "Lactobacillus bulgaricus" and "Streptococcus thermophilus", as regulated by the FDA.
   The basic mechanism for fermentation remains present in all cells of higher organisms. Mammalian muscle carries out the fermentation that occurs during periods of intense exercise where oxygen supply becomes limited, resulting in the creation of lactic acid. In invertebrates, fermentation also produces succinate and alanine.
  
presuppositions: Yogurt cultures are not killed during digestion cultures in yoghurt are not killed in your stomach.
corrections: Yogurt cultures are killed during digestion but at a lower rate than they multiply. They do get kiled in your stomach, they do their job then get broken down or used in your gut. 
raw_presuppositions: Yogurt cultures are not killed during digestion cultures in yoghurt are not killed in your stomach.
raw_corrections: Yogurt cultures are killed during digestion but at a lower rate than they multiply. They do get kiled in your stomach, they do their job then get broken down or used in your gut. 