Monday, February 28, 2011

What Is Milk Kefir? (Part 1 - LACTOBACILLI)

Now that we have taken a look at how milk kefir grains made their way out of the Caucasus Mountains to the rest of the world, let's take a look at what makes up a milk kefir grain.  Although not every single batch of milk kefir will have all of these organisms in them, the following are some of the organisms that have been commonly found diligently working within the grains.  The following list of Lactobacilli bacterium originate from a list at Dom's Kefir, located HERE.

LACTOBACILLI

Lb. acidophilus
Lb. brevis
Lb. casei
Lb. casei rhamnosus (Lactobacillus GG)
Lb. paracasei subsp. paracasei 
Lb. fermentum
Lb. cellobiosus
Lb. delbrueckii subspecies bulgaricus 
Lb. delbrueckii subsp. lactis
Lb. fructivorans
Lb. helveticus subsp. lactis
Lb. hilgardii 
Lb. helveticus 
Lb. kefiri
Lb. kefiranofaciens subsp. kefirgranum 
Lb. kefiranofaciens subsp. kefiranofaciens
Lb. parakefiri 
Lb. plantarum


Lb. acidophilus (meaning acid-loving milk-bacterium) is a species in the genus Lactobacillus. L. acidophilus is a homo-fermentative species, fermenting sugars into lactic acid, which grows readily at rather low pH values (below pH 5.0) and has an optimum growth temperature of 37 °C (98.6 °F)[citation needed]. L. acidophilus occurs naturally in the human and animal gastrointestinal tract, mouth, and vagina.[1] Some strains of L. acidophilus may be considered to have probiotic characteristics.[2] These strains are commercially used in many dairy products, sometimes together with S. salivarius ssp. thermophilus and Lactobacillus delbrueckii ssp. bulgaricus in the production of acidophilus-type yogurt.

L. acidophilus is part of the normal vaginal
flora.[3] The acid produced by L. acidophilus in the vagina may help to control the growth of the fungus Candida albicans, thus helping to prevent vaginal yeast infections. The same beneficial effect has been observed in cases of oral or gastrointestinal Candidiasis infections. Certain spermicides and contraceptive creams can kill L. acidophilus in the vagina, clearing the path to possible yeast infections.
http://www.curetoothdecay.com/Tooth_Decay/germs_cavities.htm
http://en.wikipedia.org/wiki/Lactobacillus_acidophilus

Lb. brevis is a species of lactic acid bacteria. It can be found in many different environments and in fermented foods such as sauerkraut and pickles. It is also one of the most common causes of beer spoilage. Ingestion has been shown to improve human immune function, and it has been patented several times.

L. brevis is one of the major Lactobacillus species found in
tibicos grains (aka water kefir grains), and has been identified as the species responsible for the production of the polysaccharide (dextran) that forms the grains.[1] Major metabolites of L. brevis include lactic acid and ethanol. Strains of L. brevis and L. hilgardii have been found to produce the biogenic amines tyramine and phenylethylamine.
http://bioweb.usu.edu/emlab/current%20news.html
http://en.wikipedia.org/wiki/Lactobacillus_brevis

Lb. casei is a species of genus Lactobacillus found in the human intestine and mouth. As a lactic acid producer, it has been found to assist in the propagation of desirable bacteria. This particular species of lactobacillus is documented to have a wide pH and temperature range, and complements the growth of L. acidophilus, a producer of the enzyme amylase (a carbohydrate-digesting enzyme). It is known[by whom?] to improve digestion and reduce lactose intolerance and constipation.

The most common application of L. casei is industrial, specifically for
dairy production. However, a team of scientists from Simón Bolívar University in Caracas, Venezuela found that, by using Lactobacillus casei bacteria in the natural fermentation of beans, the beans contained lower amounts of the compounds causing flatulence upon digestion.

Lactobacillus casei is typically the dominant species of non-starter lactic acid bacteria (NSLAB) present in ripening Cheddar cheese, and, recently, the complete genome sequence of L. casei
ATCC 334 has become available. L. casei is also the dominant species in naturally fermented Sicilian green olives.[1]

A commercial beverage containing L. casei strain Shirota has been shown to inhibit the growth of H. pylori in a test tube. But, when the same beverage was consumed by humans in a small trial, H. pylori colonization decreased only slightly, and the trend was not statistically significant.[2] Some L. casei are considered as probiotic and may be effective in alleviation of gastrointestinal pathogenic bacterial diseases. According to World Health Organization, those properties have to be demonstrated on each specific strain—including human clinical studies—to be valid.[3]

Among the best-documented, probiotics L.casei, L. casei DN-114001, and L. casei Shirota have been extensively studied and are widely available as functional foods (see Actimel, Yakult).

In the past few years, there have been many studies in the decolorization of azo dyes by lactic acid bacteria such as L. casei TISTR 1500, L. paracasei, Oenococcus oeni. With the
azoreductase activity, mono-, di- azo bonds are degraded completely, and generate other aromatic compounds as intermediates.[4]
http://bioweb.usu.edu/emlab/current%20news.html
http://en.wikipedia.org/wiki/Lactobacillus_casei

Lb. casei rhamnosus (Lactobacillus GG)  is a name given in honor its discoverers, Drs. Sherwood Gorbach and Barry Golden who isolated the bacterium in 1985. Lactobacillus GG does survive and grow in the acidic environment of the digestive tract. Once there, it shows an exceptional ability to adhere to the intestinal mucosa and proliferate.
According to the November 1999 Journal of Pediatrics, when it was given to children who were taking antibiotics for minor bacterial infections, Lactobacillus GG reduced the number and severity of the bouts of diarrhea, including those hospitalized with rotavirus. It has also been successful in eradicating Clostridium difficile in patients with relapsing colitis. During research experiments,Lactobacillus GG demonstrated the ability to inhibit chemically induced intestinal tumors, as well as binding to some chemical carcinogens.

Lactobacillus GG and Bifidobacterium lactis were found to produce significant improvement of atopic eczema in children with food allergies. Lactobacillus GG along with other lactic acid bacteria, including strains of Lactobacillus acidophilus, Lactobacillus bulgaricus, Bifidobaterium longum and Streptococcus thermophilus, have also demonstrated antioxidative ability, especially the chelation of metal ions, particularly iron and copper.

http://bio-nin.com/Chinese/Probiotic%20Organisms-Lactoc.htm

Lb. paracasei subsp. paracasei  Recent studies have shown that probiotics are beneficial in T-cell-mediated inflammatorydiseases. The molecular mechanism by which probiotics work remains elusive, but accumulating evidence indicates that probiotics can modulate immune cell responses. Since T cells express receptors for bacterial products or components, we examined whether different strains of lactobacilli directly regulate the functions of human T cells. CD4+ T cells were isolated from blood and intestinal lamina propria (LP) of normal individuals and patients with inflammatory bowel disease (IBD). Mononuclear cells were also isolated from Peyer's patches. Cells were activated with anti-CD3/CD2/CD28 in the presence or absence of Lactobacillus paracasei subsp. paracasei B21060, L. paracasei subsp. paracasei F19, or L. casei subsp. casei DG. Cell proliferation and death, Foxp3, intracellular pH, and cytokine production were evaluated by flow cytometry. We showed that L. paracasei subsp. paracasei B21060 but neither L. paracasei subsp. paracasei F19 nor L. casei subsp. casei DG inhibited blood CD4+ T-cell growth. This effect was associated with no change in cell survival, expression of Foxp3, or production of gamma interferon, interleukin-4 (IL-4), IL-5, and IL-10. L. paracasei subsp. paracasei B21060-mediated blockade of CD4+ T-cell proliferation required a viable bacterium and was associated with decreased MCT-1 expression and low intracellular pH. L. paracasei subsp. paracasei B21060 also inhibited the growth of Peyer's patch mononuclear cells, normal lymphocytes, and IBD CD4+ LP lymphocytes without affecting cytokine production. The data show that L. paracasei subsp. paracasei B21060 blocks T-cell growth, thus suggesting a mechanism by which these probiotics could interfere with T-cell-driven immune responses.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1865705/

Lb. fermentum is a Gram-positive species of bacterium in the genus Lactobacillus. It is associated with active dental caries lesions.[1] It is also commonly found in fermenting animal and plant material.[2] It has been found in sourdough.[3] A few strains are considered probiotic or "friendly" bacteria in animals [4] and at least one strain has been applied to treat urogenital infections in women.[5] Some strains of lactobacilli formerly classified as Lactobacillus fermentum (such as RC-14) have since been reclassified as Lactobacillus reuteri.[6] Commercialized strains of L. fermentum used as probiotics include PCC[7] and ME-3.[8]
http://en.wikipedia.org/wiki/Lactobacillus_fermentum

Lb. cellobiosus is validly published, but the species is often neglected in taxonomic studies, due to its high similarity to Lactobacillus fermentum. In the present paper, literature data concerning the two species were reviewed. Phylogenetic placement of L. cellobiosus was obtained based on 16S rDNA sequences, and genetic similarity was further investigated by comparing partial recA gene sequences for the type strains of L. cellobiosus and L. fermentum. Based on the high identity values for 16S rDNA (99 %) and recA gene (98 %) sequences, the results of DNA-DNA hybridization assays and phenotypic traits available from the literature, it is proposed that L. cellobiosus be reclassified and, as a rule of priority, renamed as L. fermentum, the first described species.
http://www.ncbi.nlm.nih.gov/pubmed/15143028
http://www.sciencephoto.com/images/download_lo_res.html?id=662201569

Lb. delbrueckii subspecies bulgaricus  (until 1984 known as Lactobacillus bulgaricus) is one of several bacteria used for the production of yoghurt. It is also found in other naturally fermented products. First identified in 1905 by the Bulgarian doctor Stamen Grigorov The name L. bulgaricus is derived from the country Bulgaria where it was first used to preserve milk. The bacterium feeds on milk to produce lactic acid which is used to preserve milk. Lactobacillus delbrueckii subsp. bulgaricus, a starter for making yogurt and unlike other starters for making yogurt Lactobacilus acidophillus, Bifidobacterium etc.,Lactobacillus delbrueckii subsp. bulgaricus disappears from the intestine within two weeks after yogurt consumption is stopped. Because of the ability of yogurt-fermenting bacteria to break down milk sugar (or lactose), people intolerant to dairy products due to lactase enzyme deficiency can usually eat yogurt. Some strains of bulgaricus also produce antibiotics, which kill harmful bacteria. By manufacturing lactic acid (from lactose), bulgaricus provides a good environment for the resident bacteria such as acidophilus and the bifidobacteria.The bacteria is helpful to people suffering from lactose intolerance which occurs in individuals who lack the enzyme to break down lactose to simple sugars. It is a Gram-positive rod that may appear long and filamentous. It is also non-motile, and it does not form spores. This bacterium is regarded as aciduric or acidophilic, since it requires a low pH (around 5.4-4.6) to grow effectively.


The bacterium has complex nutritional requirements, including the inability to ferment any sugar except lactose[citation needed], from which it produces lactic acid, which gives yogurt its tart flavor and acts as a preservative. The bacterium also partially coagulates the milk proteins. While fermenting milk, it produces acetaldehyde, which is one of the main yogurt aroma components.


It is often helpful to sufferers of lactose intolerance,[citation needed] whose digestive systems lack the enzymes to break down lactose to simpler sugars.http://users.sa.chariot.net.au/~dna/kefirpage.html#traditional-kefir 
http://bioweb.uwlax.edu/bio203/s2007/kahl_ambe/
http://en.wikipedia.org/wiki/Lactobacillus_delbrueckii_subsp._bulgaricus

Lb. delbrueckii subsp. lactis AIMS: The aim of the present study was to assess the ability of a potentially probiotic strain to resist, in vitro, the effect of intestinal antimicrobial molecules.

METHODS AND RESULTS: Strain CIDCA 133 of Lactobacillus delbrueckii subsp lactis was studied. Lactobacillus delbrueckii subsp bulgaricus as well as other gram-positive and gram-negative bacteria were used for comparison purposes. The effect of different antimicrobial extracts was determined by diffusion assays, viable counts and growth kinetics. Human-defensins (h beta D1 and h beta D2) were also included in the study. Two types of cellular fractions from Caco-2 cells were tested: (i) cytosolic fractions, obtained by sonication of cultured human enterocytes and (ii) cationic fraction, obtained by batch extraction of the cytosolic fraction with a weak cation exchange resin. In addition, the effect of Caco-2-secreted factors was studied. Strain CIDCA 133 was neither inhibited by Caco-2 secreted, cytosolic nor cationic fractions. Of note, human-defensins were inactive against strain CIDCA 133. In contrast, a related lactobacilli: Lactobacilli delbrueckii subsp bulgaricus (strain CIDCA 331) and other species of gram-positive or gram-negative bacteria were strongly inhibited.

CONCLUSIONS: Strain CIDCA 133 is able to survive and grow in the presence of enterocyte-derived antimicrobial molecules. This ability is not a general property of lactobacilli.

SIGNIFICANCE AND IMPACT OF THE STUDY: Results could provide a new insight into the mechanisms of the probiotic effect and encourage further studies on this field. Resistance to antimicrobial peptides can be relevant to understand the interaction of potentially probiotic strains with the host's immune system. This ability can be also relevant as a selection criterion for new probiotic strains
.
http://www.magma.ca/~pavel/science/L_bulgaricus.htm
http://www.ncbi.nlm.nih.gov/pubmed/20088979

Lb. fructivorans Associated with the spoilage of ketchup in counts of 10(5) CFU/g. The spoiled strain of this organism was discovered after isolation from saled dressing. Known for spoiling acidic or ethanol containing sources, such as mayonnaise, saled dressing, vinegar preserves, sake, desert wines and aperatifs.
https://helda.helsinki.fi/bitstream/handle/1975/554/tomato_ketchup_ocr.pdf?sequence=2

Lb. helveticus subsp. lactis  Lactobacillus helveticus is a lactic-acid producing rod shaped bacterium of the genus Lactobacillus. It is most commonly used in the production of American Swiss cheese and Emmental cheese but is also sometimes used in making other styles of cheese, such as Cheddar, Parmesan, romano, provolone, and mozzarella. The primary function of L. helveticus culture is to prevent bitterness and produce nutty flavors in the final cheese. In Swiss and Emmental cheese production, L. helveticus is used in conjunction with a Propionibacter culture, which is responsible for developing the holes (known as "eyes") through production of carbon dioxide gas.

Ingestion of powdered milk fermented with L. helveticus was shown to decrease blood pressure due to the presence of manufactured tripeptides that have ACE inhibitor activity. However, there have been several contradictory results in later studies.

The bacterium's specific name is an adjective derived from "Helvetia", the Latin name for the region occupied by the ancient Helvetii.

http://www.probiotic-cn.com/Lactobacillus_Helveticus.html

Lb. hilgardii  Conventional phenotypic methods lead to misidentification of the lactic acid bacteria Lactobacillus hilgardii and Lactobacillus brevis. Random amplified polymorphic DNA (RAPD) and repetitive element PCR (REP-PCR) techniques were developed for a molecular study of these two species. The taxonomic relationships were confirmed by analysis of the ribosomal operon. Amplified DNA fragments were chosen to isolate L. hilgardii-specific probes. In addition to rapid molecular methods for identification of L. hilgardii, these results convincingly proved that some strains first identified as L. brevis must be reclassified as L. hilgardii. The data clearly showed that these molecular methods are more efficient than phenotypic or biochemical studies for bacterial identification at the species level.
http://bioweb.usu.edu/emlab/current%20news.html
http://ijs.sgmjournals.org/cgi/content/abstract/49/3/1075

Lb. helveticus  is a lactic-acid producing rod shaped bacterium of the genus Lactobacillus. It is most commonly used in the production of American Swiss cheese and Emmental cheese but is also sometimes used in making other styles of cheese, such as Cheddar, Parmesan, romano, provolone, and mozzarella. The primary function of L. helveticus culture is to prevent bitterness and produce nutty flavors in the final cheese. In Swiss and Emmental cheese production, L. helveticus is used in conjunction with a Propionibacter culture, which is responsible for developing the holes (known as "eyes") through production of carbon dioxide gas.

Ingestion of powdered milk fermented with L. helveticus was shown to decrease
blood pressure due to the presence of manufactured tripeptides that have ACE inhibitor activity.[1] However, there have been several contradictory results in later studies.[2][3][4]

The bacterium's specific name is an adjective derived from "Helvetia", the Latin name for the region occupied by the ancient Helvetii (and for modern Switzerland).
http://www2.unibas.it/parente/Starter/gruppi.html

Lb. kefiri DSM 20587 cells were immobilized in calcium alginate and carrageenan. The immobilized cells were used as biocatalysts for the enantioselective reduction of the methyl ketone group of denbufylline to synthesize the enantiopure (R)-hydroxy metabolite: (−)-1,3-dibutyl-7-((2′R)-hydroxypropyl)-1H-purine-2,6(3H,7H)-dione (1). The experimental conditions for the biotransformation were optimized. As denbufylline is insoluble in aqueous media, the influence of cosolvents (dimethylsulfoxide (DMSO), acetonitrile) and different concentrations of each solvent in the reaction mixture on the yield and enantiomeric excess of the final biotransformation product was studied. The maximum biotransformation yield (96–98%) and highest enantioselectivity (96% ee) for the obtained metabolite were reached using DMSO as a cosolvent at a concentration of 7.5% (v/v) in the presence of L. kefiri immobilized either in calcium alginate or in carrageenan. The absolute configuration of the stereogenic center of 1 was determined by applying Mosher's method. Chirality 2009. © 2008 Wiley-Liss, Inc.

Lb. kefiranofaciens subsp. kefirgranum  Twelve strains of homofermentative lactobacilli and two strains of heterofermentative lactobacilli were isolated from kefir grains by using R-CW agar medium. The physiological and biochemical characteristics, DNA guanine-plus-cytosine contents, and levels of DNA-DNA relatedness of these isolates and previously described lactobacilli were compared. Our results indicated that two new species, Lactobacillus kefirgranum and Lactobacillus parakefir, could be distinguished. The type strain of L. kefirgranum sp. nov. is GCL 1701 (= JCM 8572), and the type strain of L. parakefir sp. nov. is GCL 1731 (= JCM 8573). http://ijs.sgmjournals.org/cgi/content/abstract/44/3/435

Lb. kefiranofaciens subsp. kefiranofaciens  A new fermented milk was prepared by using capsular polysaccharide-producing Lactobacillus kefiranofaciens K1 isolated from kefir grains. Fermentation was carried out at 30°C for 18 h, when pH 4·5 was attained. The product had a ropy consistency and was resistant to syneresis. However, the product was given lower scores for acceptability by a consumer panel than a similar product made with Lb. delbrueckii subsp. bulgaricus.
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=5162608

Lb. parakefiri  Lactobacillus kefirgranum sp. nov. and Lactobacillus parakefir sp. nov., two new species from kefir grains
http://www.straininfo.net/publications/4894


Lb. plantarum is a widespread member of the genus Lactobacillus, commonly found in many fermented food products as well as anaerobic plant matter. It is also present in saliva (from which it was first isolated). It has the ability to liquefy gelatin.[1] L. plantarum has one of the largest genomes known among the lactic acid bacteria and is a very flexible and versatile species.
http://www.bacferm.com.au/silac/micro/micro.html
http://en.wikipedia.org/wiki/Lactobacillus_plantarum