{
    "id": 29209,
    "date": "2026-11-12T20:24:55",
    "date_gmt": "2026-11-12T12:24:55",
    "guid": {
        "rendered": "https:\/\/kefir.link\/zh-tw\/?p=29209"
    },
    "modified": "2026-11-12T21:05:22",
    "modified_gmt": "2026-11-12T13:05:22",
    "slug": "what-bacteria-are-in-kefir",
    "status": "publish",
    "type": "post",
    "link": "https:\/\/kefir.link\/en\/what-bacteria-are-in-kefir\/",
    "title": {
        "rendered": "What Bacteria Are in Kefir? Why the Bottle Has No Strain List"
    },
    "content": {
        "rendered": "<div data-elementor-type=\"wp-post\" data-elementor-id=\"29209\" class=\"elementor elementor-29209\" data-elementor-post-type=\"post\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-9922901 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"9922901\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-9922902\" data-id=\"9922902\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-9922903 elementor-widget elementor-widget-shortcode\" data-id=\"9922903\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"shortcode.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-shortcode\"><trp-tag data-no-translation><div class=\"k10\" lang=\"en\">\n<aside class=\"k10-rail\"><nav class=\"k10-toc\" aria-label=\"On this page\"><p class=\"k10-toc-title\">On this page<\/p><ol><li><a href=\"#takeaways\">The short answer<\/a><\/li><li><a href=\"#how-we-checked\">How we checked<\/a><\/li><li><a href=\"#grains\">What kefir grains are<\/a><\/li><li><a href=\"#history\">Where they came from<\/a><\/li><li><a href=\"#world\">Why grains differ<\/a><\/li><li><a href=\"#taste\">Temperature and who leads<\/a><\/li><li><a href=\"#sequencing\">Why not test the strains<\/a><\/li><li><a href=\"#yogurt\">Yogurt and kefir<\/a><\/li><li><a href=\"#species\">Species and strains<\/a><\/li><li><a href=\"#research\">What researchers find<\/a><\/li><li><a href=\"#tests\">What we check<\/a><\/li><li><a href=\"#faq\">FAQ<\/a><\/li><li><a href=\"#papers\">Research papers<\/a><\/li><\/ol><\/nav><div class=\"k10-railcta\"><p class=\"k10-railcta-eye\">\u6771\u6b50\u56b4\u9078\uff5ckefir.link<\/p><p class=\"k10-railcta-title\">Fermented with living kefir grains.<\/p><p class=\"k10-railcta-text\">Every bottle starts with fresh milk and living grains. Our SGS report shows what we measure.<\/p><a class=\"k10-railcta-btn\" href=\"\/en\/food-test-report\/\">See the SGS report \u2192<\/a><\/div><\/aside>\n<div class=\"k10-main\">\n<p class=\"k10-byline\"><img src=\"\/wp-content\/uploads\/2026\/10\/chef-nik-author.webp\" width=\"176\" height=\"176\" alt=\"\" decoding=\"async\">By <a href=\"\/en\/about-us\/\" rel=\"author\"><strong>Nik<\/strong><\/a>, founder of \u6771\u6b50\u56b4\u9078\uff5ckefir.link and former chef \u00b7 Published 12 November 2026<\/p>\n<p class=\"k10-lead\">\u201cWhich bacteria are in your kefir?\u201d \u201cWhy are the strains not listed on the bottle?\u201d We hear these two questions on LINE almost every week, and they are fair questions. Yogurt in the supermarket lists its cultures, and everyone says to check the strain code when buying probiotics. Kefir is different because nobody chooses its bacteria. It is fermented with kefir grains, a living community of bacteria and yeasts that is a little different in every kitchen in the world, and a little different in every batch.<\/p>\n\n<section class=\"k10-takeaways\">\n<h2 id=\"takeaways\">The short answer<\/h2>\n<ul>\n<li><strong>Kefir grains are alive.<\/strong> They look like small cauliflower florets and hold many kinds of bacteria and yeasts living together.<\/li>\n<li><strong>No two grains are the same.<\/strong> People have handed grains from one kitchen to the next for centuries, so every kitchen\u2019s grains are a little different.<\/li>\n<li><strong>Every batch shifts a little<\/strong> with the season, the milk and the temperature.<\/li>\n<li><strong>So a strain test would describe one bottle only.<\/strong> We measure what holds for every bottle: in April 2024 SGS counted 57 billion live lactic acid bacteria in 100 g of our milk kefir, 57 times the national standard for fermented milk.<\/li>\n<\/ul>\n<p class=\"k10-ctas\"><a class=\"k10-btn k10-btn--yellow\" href=\"\/en\/food-test-report\/\">See the SGS report<\/a><a class=\"k10-btn k10-btn--ghost\" href=\"https:\/\/lin.ee\/ZI19qB8\" rel=\"noopener\" target=\"_blank\">Ask us on LINE<\/a><\/p>\n<\/section>\n\n<h2 id=\"how-we-checked\">How we checked<\/h2>\n<ul class=\"k10-points\">\n<li><strong>Research:<\/strong> reviews and studies of kefir grains, read in six languages. Each one is linked beside the sentence it supports and listed at the end.<\/li>\n<li><strong>Our lab report:<\/strong> the SGS test of our milk kefir from April 2024.<\/li>\n<\/ul>\n\n<h2 id=\"grains\">What are kefir grains?<\/h2>\n<figure class=\"kg\">\n<div class=\"kg-stage\" tabindex=\"0\" role=\"group\" aria-label=\"A 3D kefir grain. Drag to turn it, or use the buttons to look inside.\">\n<img loading=\"lazy\" class=\"kg-poster\" src=\"\/wp-content\/plugins\/kefir-link-storefront\/assets\/grain3d\/grain-poster.webp\" width=\"640\" height=\"577\" alt=\"A kefir grain: a creamy white lump that looks like a small cauliflower floret\" decoding=\"async\">\n<canvas><\/canvas>\n<div class=\"kg-mode\" role=\"group\" aria-label=\"View\"><button type=\"button\" data-mode=\"0\" aria-pressed=\"true\">Outside<\/button><button type=\"button\" data-mode=\"1\" aria-pressed=\"false\">Look inside<\/button><\/div>\n<p class=\"kg-hint\" data-out=\"Try it: drag to turn the grain, tap it to look inside\" data-in=\"Tap the grain again to close it\">Try it: drag to turn the grain, tap it to look inside<\/p>\n<\/div>\n<div class=\"kg-chips\" role=\"group\" aria-label=\"Who lives inside\"><button type=\"button\" data-g=\"all\" aria-pressed=\"true\" disabled>All together<\/button><button type=\"button\" data-g=\"lab\" aria-pressed=\"false\" disabled><i class=\"c-lab\"><\/i>Lactic acid bacteria<\/button><button type=\"button\" data-g=\"yeast\" aria-pressed=\"false\" disabled><i class=\"c-yeast\"><\/i>Yeasts<\/button><button type=\"button\" data-g=\"aab\" aria-pressed=\"false\" disabled><i class=\"c-aab\"><\/i>Acetic acid bacteria<\/button><\/div>\n<p class=\"kg-info\" aria-live=\"polite\" data-sep=\" \" data-out-t=\"This is a kefir grain.\" data-out=\"It is soft, springy and alive. The slippery coat is kefiran, a gel the bacteria make themselves. Tap the grain to see who lives inside.\" data-all-t=\"They live together.\" data-all=\"The bacteria and the yeasts pass what they make to each other as food. The bright dots show that exchange. The cloudy veil around them is kefiran, the gel that holds the whole community together.\" data-lab-t=\"Lactic acid bacteria.\" data-lab=\"They turn the milk sugar into lactic acid, so the milk becomes sour and thick. One of them also makes kefiran, the gel around the grain.\" data-yeast-t=\"Yeasts.\" data-yeast=\"They are much bigger than the bacteria. They make carbon dioxide, which is why kefir has a fine fizz.\" data-aab-t=\"Acetic acid bacteria.\" data-aab=\"There are fewer of them. They make a little acetic acid.\"><b>This is a kefir grain.<\/b> It is soft, springy and alive. The slippery coat is kefiran, a gel the bacteria make themselves.<\/p>\n<figcaption class=\"kg-cap\">A model, not a photo. Real microbes are far too small to see without a microscope; here they are drawn many times larger.<\/figcaption>\n<\/figure>\n<p>Many people hear \u201cgrains\u201d and picture a powder from a laboratory. Kefir grains are something you can see and hold: soft, white, springy lumps that look like small florets of cauliflower.<\/p>\n<p>Inside, it is crowded. Lactic acid bacteria, yeasts and a few acetic acid bacteria live together and pass food to each other. This way of living together is called symbiosis <span class=\"k10-cite\">(<a href=\"https:\/\/www.frontiersin.org\/journals\/microbiology\/articles\/10.3389\/fmicb.2015.01177\/full\" rel=\"noopener\" target=\"_blank\">Prado and colleagues, 2015<\/a>)<\/span>.<\/p>\n<p>They all sit in a soft gel called kefiran, which the bacteria make themselves. Kefiran wraps the whole community and holds it together <span class=\"k10-cite\">(<a href=\"https:\/\/www.gov.mb.ca\/agriculture\/food-safety\/education-resources\/pubs\/fermented-kefir.pdf\" rel=\"noopener\" target=\"_blank\">BC Centre for Disease Control, 2024<\/a>)<\/span>. It is the slippery coat you feel on a healthy grain.<\/p>\n\n<h2 id=\"history\">Where did kefir grains come from?<\/h2>\n<p>Nobody invented kefir grains, and nobody knows exactly how the first one formed <span class=\"k10-cite\">(<a href=\"https:\/\/doi.org\/10.5493\/wjem.v15.i4.112191\" rel=\"noopener\" target=\"_blank\">Katchieva and colleagues, 2025<\/a>)<\/span>. Kefir comes from the Caucasus mountains, where families fermented milk in bags made of sheep or goat skin <span class=\"k10-cite\">(<a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC4854945\/\" rel=\"noopener\" target=\"_blank\">Bourrie and colleagues, 2016<\/a>)<\/span>.<\/p>\n<p>Two stories are told there. In one, soft white lumps were found in the folds of a skin bag in which milk had soured again and again. In the other, the lumps grew on pieces of calf stomach kept in goat\u2019s milk. Science has not settled it.<\/p>\n<p>Kefir is certainly old: the DNA of a kefir bacterium was found in cheese about 3,600 years old from a desert cemetery in Xinjiang <span class=\"k10-cite\">(<a href=\"https:\/\/doi.org\/10.1016\/j.cell.2024.08.008\" rel=\"noopener\" target=\"_blank\">Liu and colleagues, 2024<\/a>; see <a href=\"\/en\/they-found-3600-year-old-cheese-in-china-its-kefir\/\">our article on that cheese<\/a>)<\/span>. As far as published reviews report, laboratories have not yet rebuilt a traditional grain from separate cultures. In practice, new grains grow from old grains.<\/p>\n\n<h2 id=\"world\">Why are grains different all around the world?<\/h2>\n<p>Because kefir grains are handed on, never manufactured. Each line of grains has its own history: where it came from, which milk it was fed and how warm its kitchen was.<\/p>\n<p>When researchers compared 25 kefir grains from 8 countries, almost every grain had the same leading bacteria, and the smaller members differed from grain to grain <span class=\"k10-cite\">(<a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC3716650\/\" rel=\"noopener\" target=\"_blank\">Marsh and colleagues, 2013<\/a>)<\/span>. A larger study of 64 grains from 25 countries found the same: grains did not sort by country <span class=\"k10-cite\">(<a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10568436\/\" rel=\"noopener\" target=\"_blank\">Walsh and colleagues, 2023<\/a>)<\/span>. They differ from kitchen to kitchen, not from country to country.<\/p>\n<p>The mix keeps moving at home, too. Taiwanese milk is richer in winter than in summer <span class=\"k10-cite\">(<a href=\"https:\/\/www.foodnext.net\/life\/health2\/paper\/4975310736\" rel=\"noopener\" target=\"_blank\">Food Next, in Chinese<\/a>)<\/span>, so the same grains make a slightly different kefir in January and in July.<\/p>\n\n<h2 id=\"taste\">Which microbes lead at which temperature?<\/h2>\n<p>The same grains grow a different mix of microbes in a cool kitchen and in a hot one. Move the temperature and see what studies found, and which species can grow there at all.<\/p>\n<figure class=\"kt\" data-w0=\"none found\" data-w1=\"a few\" data-w2=\"some\" data-w3=\"many\" data-w4=\"the most\" data-ev-m=\"measured\" data-ev-w=\"one small study\" data-ev-e=\"judged from alcohol, not counted\" data-ev-t=\"all lactic acid bacteria counted together\" data-ev-n=\"not measured\" data-st-on=\"can grow\" data-st-edge=\"at its limit\" data-st-off=\"resting\" data-ax=\"0,48\">\n<div class=\"kt-data\" hidden><i class=\"kt-d\" data-t=\"6\" data-label=\"Fridge\" data-title=\"In the fridge, everything slows down\" data-text=\"Lactic acid bacteria stay numerous, but less alcohol forms, a sign that the yeasts are quieter. One study found no Leuconostoc after 3 to 9 days at 4 \u00b0C.\" data-lv=\"3,1,1,0\" data-ev=\"t,n,e,n\" data-cold=\"1\" data-heat=\"0.0\"><\/i><i class=\"kt-d\" data-t=\"19\" data-label=\"19 \u00b0C\" data-title=\"In a cool room, yeasts do well\" data-text=\"In one small study the yeasts were at their highest at about 19 \u00b0C, and the acetic acid bacteria at their lowest. Grains kept at 20 \u00b0C stayed the same over many batches.\" data-lv=\"3,2,3,0\" data-ev=\"w,n,w,w\" data-cold=\"0\" data-heat=\"0.25\"><\/i><i class=\"kt-d\" data-t=\"25\" data-label=\"25 \u00b0C\" data-title=\"At about 25 \u00b0C, round lactic acid bacteria lead\" data-text=\"Round lactic acid bacteria, such as lactococci, outnumbered the rod-shaped ones about a thousand to one. Yeasts were plentiful, no acetic acid bacteria were found, and this kefir got the best taste score.\" data-lv=\"4,1,2,0\" data-ev=\"m,m,m,m\" data-cold=\"0\" data-heat=\"0.5\"><\/i><i class=\"kt-d\" data-t=\"30\" data-label=\"30 \u00b0C\" data-title=\"At about 30 \u00b0C, the rods catch up\" data-text=\"The rod-shaped lactobacilli caught up with the round ones, acetic acid bacteria appeared, and the taste score dropped. Grains reused again and again at 30 \u00b0C lost some of their yeasts.\" data-lv=\"4,4,2,1\" data-ev=\"m,m,m,m\" data-cold=\"0\" data-heat=\"0.75\"><\/i><i class=\"kt-d\" data-t=\"35\" data-label=\"35 \u00b0C\" data-title=\"At about 35 \u00b0C, yeasts fall back\" data-text=\"Rod-shaped bacteria and yeasts fell about tenfold, and the taste score was the lowest. Grains reused at 37 \u00b0C got damaged.\" data-lv=\"4,3,1,1\" data-ev=\"m,m,m,m\" data-cold=\"0\" data-heat=\"1.0\"><\/i><\/div>\n<div class=\"kt-ctl\"><label class=\"kt-lab\" for=\"kt-temp\"><span class=\"kt-try\">Try it<\/span><span class=\"kt-cue\">Drag the dot to change the temperature<\/span><\/label><div class=\"kt-slide\"><output class=\"kt-bub\" for=\"kt-temp\">25 \u00b0C<\/output><input class=\"kt-range kt-temp\" id=\"kt-temp\" type=\"range\" min=\"0\" max=\"4\" step=\"1\" value=\"2\" aria-valuetext=\"25 \u00b0C\"><\/div><div class=\"kt-ticks\"><button type=\"button\" class=\"kt-tick\" tabindex=\"-1\">Fridge<\/button><button type=\"button\" class=\"kt-tick\" tabindex=\"-1\">19 \u00b0C<\/button><button type=\"button\" class=\"kt-tick is-on\" tabindex=\"-1\">25 \u00b0C<\/button><button type=\"button\" class=\"kt-tick\" tabindex=\"-1\">30 \u00b0C<\/button><button type=\"button\" class=\"kt-tick\" tabindex=\"-1\">35 \u00b0C<\/button><\/div><\/div>\n<div class=\"kt-top\"><div class=\"kt-art\"><canvas class=\"kt-jar\" width=\"300\" height=\"320\" aria-hidden=\"true\"><\/canvas><\/div><div class=\"kt-side\" aria-live=\"polite\"><p class=\"kt-eyebrow\">What studies measured in kefir<\/p><p class=\"kt-title\">At about 25 \u00b0C, round lactic acid bacteria lead<\/p><p class=\"kt-text\">Round lactic acid bacteria, such as lactococci, outnumbered the rod-shaped ones about a thousand to one. Yeasts were plentiful, no acetic acid bacteria were found, and this kefir got the best taste score.<\/p><ol class=\"kt-list\"><li class=\"kt-row kt-row--round is-lead\" data-g=\"round\" data-shape=\"chain\" data-col=\"#3F8FD1\" style=\"--w:100%\"><span class=\"kt-mk\" aria-hidden=\"true\"><\/span><span class=\"kt-name\">Round lactic acid bacteria<\/span><i class=\"kt-bar\" aria-hidden=\"true\"><\/i><em class=\"kt-v\">the most<\/em><small class=\"kt-ev\">measured<\/small><\/li><li class=\"kt-row kt-row--rod\" data-g=\"rod\" data-shape=\"long\" data-col=\"#2E6FA8\" style=\"--w:25%\"><span class=\"kt-mk\" aria-hidden=\"true\"><\/span><span class=\"kt-name\">Rod-shaped lactic acid bacteria<\/span><i class=\"kt-bar\" aria-hidden=\"true\"><\/i><em class=\"kt-v\">a few<\/em><small class=\"kt-ev\">measured<\/small><\/li><li class=\"kt-row kt-row--yeast\" data-g=\"yeast\" data-shape=\"bud\" data-col=\"#E9B81C\" style=\"--w:50%\"><span class=\"kt-mk\" aria-hidden=\"true\"><\/span><span class=\"kt-name\">Yeasts<\/span><i class=\"kt-bar\" aria-hidden=\"true\"><\/i><em class=\"kt-v\">some<\/em><small class=\"kt-ev\">measured<\/small><\/li><li class=\"kt-row kt-row--aab\" data-g=\"aab\" data-shape=\"short\" data-col=\"#2FA892\" style=\"--w:0%\"><span class=\"kt-mk\" aria-hidden=\"true\"><\/span><span class=\"kt-name\">Acetic acid bacteria<\/span><i class=\"kt-bar\" aria-hidden=\"true\"><\/i><em class=\"kt-v\">none found<\/em><small class=\"kt-ev\">measured<\/small><\/li><\/ol><\/div><\/div>\n<div class=\"kr\"><p class=\"kr-title\">Which species can grow at this temperature?<\/p><p class=\"kr-sub\">From lab tests of each microbe on its own. In a grain they live together, so this shows who can be active, not who wins.<\/p><div class=\"kr-chart\"><i class=\"kr-mark\" aria-hidden=\"true\"><\/i><ul class=\"kr-rows\"><li class=\"kr-row kr--round\" data-a=\"15\" data-b=\"37\" data-fa=\"10\" data-fb=\"40\"><span class=\"kr-name\"><i>Lactococcus lactis<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:20.8%;width:62.5%\"><\/i><i class=\"kr-solid\" style=\"left:31.2%;width:45.9%\"><\/i><i class=\"kr-opt\" style=\"left:62.5%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--round\" data-a=\"15\" data-b=\"30\" data-fa=\"12\" data-fb=\"35\"><span class=\"kr-name\"><i>Lactococcus cremoris<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:25.0%;width:47.9%\"><\/i><i class=\"kr-solid\" style=\"left:31.2%;width:31.3%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--round\" data-a=\"10\" data-b=\"37\" data-fa=\"4\" data-fb=\"40\"><span class=\"kr-name\"><i>Leuconostoc mesenteroides<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:8.3%;width:75.0%\"><\/i><i class=\"kr-solid\" style=\"left:20.8%;width:56.3%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--rod\" data-a=\"25\" data-b=\"40\" data-fa=\"17\" data-fb=\"45\"><span class=\"kr-name\"><i>Lactobacillus kefiranofaciens<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:35.4%;width:58.4%\"><\/i><i class=\"kr-solid\" style=\"left:52.1%;width:31.2%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--rod\" data-a=\"15\" data-b=\"30\" data-fa=\"12\" data-fb=\"40\"><span class=\"kr-name\"><i>Lactobacillus kefiri<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:25.0%;width:58.3%\"><\/i><i class=\"kr-solid\" style=\"left:31.2%;width:31.3%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--rod\" data-a=\"30\" data-b=\"45\" data-fa=\"25\" data-fb=\"47\"><span class=\"kr-name\">Heat-loving lactic acid bacteria <span>(only in some grains)<\/span><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:52.1%;width:45.8%\"><\/i><i class=\"kr-solid\" style=\"left:62.5%;width:31.3%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--yeast\" data-a=\"25\" data-b=\"45\" data-fa=\"15\" data-fb=\"47\"><span class=\"kr-name\"><i>Kluyveromyces marxianus<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:31.2%;width:66.7%\"><\/i><i class=\"kr-solid\" style=\"left:52.1%;width:41.7%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--yeast\" data-a=\"5\" data-b=\"44\" data-fa=\"3\" data-fb=\"45\"><span class=\"kr-name\"><i>Saccharomyces cerevisiae<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:6.2%;width:87.6%\"><\/i><i class=\"kr-solid\" style=\"left:10.4%;width:81.3%\"><\/i><i class=\"kr-opt\" style=\"left:66.7%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--yeast\" data-a=\"5\" data-b=\"35\" data-fa=\"4\" data-fb=\"37\"><span class=\"kr-name\"><i>Kazachstania unispora<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:8.3%;width:68.8%\"><\/i><i class=\"kr-solid\" style=\"left:10.4%;width:62.5%\"><\/i><i class=\"kr-opt\" style=\"left:62.5%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><li class=\"kr-row kr--aab\" data-a=\"20\" data-b=\"34\" data-fa=\"15\" data-fb=\"37\"><span class=\"kr-name\"><i>Acetobacter<\/i><\/span><span class=\"kr-track\" aria-hidden=\"true\"><i class=\"kr-fade\" style=\"left:31.2%;width:45.9%\"><\/i><i class=\"kr-solid\" style=\"left:41.7%;width:29.1%\"><\/i><i class=\"kr-opt\" style=\"left:56.2%\"><\/i><\/span><em class=\"kr-state\"><\/em><\/li><\/ul><div class=\"kr-axis\" aria-hidden=\"true\"><span style=\"left:0.0%\">0 \u00b0C<\/span><span style=\"left:20.8%\">10 \u00b0C<\/span><span style=\"left:41.7%\">20 \u00b0C<\/span><span style=\"left:62.5%\">30 \u00b0C<\/span><span style=\"left:83.3%\">40 \u00b0C<\/span><\/div><\/div><p class=\"kr-key\"><span class=\"kr-k kr-k--solid\">grows in lab tests<\/span><span class=\"kr-k kr-k--fade\">unclear, or differs between strains<\/span><span class=\"kr-k kr-k--opt\">grows best<\/span><\/p><\/div>\n<figcaption>Studies in kefir: <a href=\"https:\/\/cheese.kemsu.ru\/ru\/storage\/download\/30946\" rel=\"noopener\" target=\"_blank\">Smirnova, 2014<\/a> (25 to 40 \u00b0C), <a href=\"https:\/\/rep.polessu.by\/bitstream\/123456789\/22555\/1\/Vliianie_temperatury.pdf\" rel=\"noopener\" target=\"_blank\">Vorokh and Lekunovich<\/a> (19 to 27 \u00b0C), <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/22717048\/\" rel=\"noopener\" target=\"_blank\">Londero, 2012<\/a>, <a href=\"https:\/\/agris.fao.org\/search\/ru\/records\/647480e22d3f560f80b18cb9\" rel=\"noopener\" target=\"_blank\">Hecer, 2019<\/a> (4 \u00b0C), <a href=\"https:\/\/jfqhc.ssu.ac.ir\/article-1-1401-en.pdf\" rel=\"noopener\" target=\"_blank\">Satiyarti, 2026<\/a> (2 to 10 \u00b0C). They counted groups of microbes, not each species. Lab growth tests: <a href=\"https:\/\/bacdive.dsmz.de\/\" rel=\"noopener\" target=\"_blank\">BacDive culture collection<\/a>, <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC8540521\/\" rel=\"noopener\" target=\"_blank\">Georgalaki, 2021<\/a>, <a href=\"https:\/\/treatment.plazi.org\/GgServer\/html\/03A8D903D230027EFFD0F9FD542233E2\" rel=\"noopener\" target=\"_blank\">Zheng, 2020<\/a>, <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC161497\/\" rel=\"noopener\" target=\"_blank\">Hamasaki, 2003<\/a>, <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC3067424\/\" rel=\"noopener\" target=\"_blank\">Salvad\u00f3, 2011<\/a>, <a href=\"https:\/\/doi.org\/10.3390\/fermentation9020101\" rel=\"noopener\" target=\"_blank\">Kondybayev, 2023<\/a>, <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC2607150\/\" rel=\"noopener\" target=\"_blank\">Nonklang, 2008<\/a>, <a href=\"https:\/\/hrcak.srce.hr\/file\/299441\" rel=\"noopener\" target=\"_blank\">Gomes, 2018<\/a>. The drawing is a simplified picture.<\/figcaption>\n<\/figure>\n\n<h2 id=\"sequencing\">Why is there no point in testing the strains?<\/h2>\n<p>A laboratory can read the genes in a sample and name the microbes it finds. This is called sequencing. It suits a product made from a few chosen strains, because every pack holds the same ones. With kefir grains it answers the wrong question.<\/p>\n<ul class=\"k10-points\">\n<li><strong>One test describes one bottle.<\/strong> The next batch has the same groups in slightly different shares.<\/li>\n<li><strong>A strain code belongs to a culture that lives alone.<\/strong> A strain gets its name after a laboratory has separated it and grown it by itself; the guidelines also recommend storing it in a culture collection <span class=\"k10-cite\">(<a href=\"https:\/\/www.fao.org\/4\/a0512e\/a0512e.pdf\" rel=\"noopener\" target=\"_blank\">FAO and WHO guidelines, 2002<\/a>)<\/span>. In a kefir grain the microbes live mixed together.<\/li>\n<li><strong>It would tell you nothing new about your bottle.<\/strong> What counts is how many live bacteria it holds and that it is safe. Those two things we measure.<\/li>\n<\/ul>\n<p class=\"k10-note\">So we tell you what stays true for every bottle, and we keep away from names we could not promise for the next batch.<\/p>\n\n<h2 id=\"yogurt\">Yogurt and kefir: where is the difference?<\/h2>\n<p>Yogurt starts with a packet of powder, kefir with living grains. The international food standard draws the same line: yogurt is defined by two named bacteria, kefir by a culture made from kefir grains <span class=\"k10-cite\">(<a href=\"https:\/\/www.fao.org\/input\/download\/standards\/400\/CXS_243e.pdf\" rel=\"noopener\" target=\"_blank\">Codex standard for fermented milks<\/a>)<\/span>.<\/p>\n<div class=\"yk\" role=\"group\" aria-label=\"Yogurt and kefir compared\">\n<div class=\"yk-h yk-h--y\"><img loading=\"lazy\" src=\"\/wp-content\/plugins\/kefir-link-storefront\/assets\/grain3d\/yk-packet.webp\" width=\"320\" height=\"320\" alt=\"A packet of yogurt starter powder\" decoding=\"async\"><p class=\"yk-name\">Ordinary yogurt<\/p><\/div><div class=\"yk-h yk-h--k\"><img loading=\"lazy\" src=\"\/wp-content\/plugins\/kefir-link-storefront\/assets\/grain3d\/yk-grains.webp\" width=\"320\" height=\"320\" alt=\"Kefir grains on a wooden spoon\" decoding=\"async\"><p class=\"yk-name\">Kefir<\/p><\/div>\n<p class=\"yk-k\"><span>Starts with<\/span><\/p><div class=\"yk-c yk-c--y\">A packet of starter powder<\/div><div class=\"yk-c yk-c--k\">Living kefir grains<\/div><p class=\"yk-k\"><span>What is inside<\/span><\/p><div class=\"yk-c yk-c--y\">A few chosen lactic acid bacteria<span class=\"yk-dots\" aria-hidden=\"true\"><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><\/span><\/div><div class=\"yk-c yk-c--k\">A large community of bacteria and yeasts<span class=\"yk-dots\" aria-hidden=\"true\"><i class=\"d-b\"><\/i><i class=\"d-y\"><\/i><i class=\"d-b\"><\/i><i class=\"d-t\"><\/i><i class=\"d-b\"><\/i><i class=\"d-y\"><\/i><i class=\"d-b\"><\/i><\/span><\/div><p class=\"yk-k\"><span>Each batch<\/span><\/p><div class=\"yk-c yk-c--y\">Always the same<span class=\"yk-batches\" aria-hidden=\"true\"><span class=\"yk-dots\" aria-hidden=\"true\"><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><\/span><span class=\"yk-dots\" aria-hidden=\"true\"><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><\/span><span class=\"yk-dots\" aria-hidden=\"true\"><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><\/span><\/span><\/div><div class=\"yk-c yk-c--k\">A little different every time<span class=\"yk-batches\" aria-hidden=\"true\"><span class=\"yk-dots\" aria-hidden=\"true\"><i class=\"d-b\"><\/i><i class=\"d-y\"><\/i><i class=\"d-b\"><\/i><\/span><span class=\"yk-dots\" aria-hidden=\"true\"><i class=\"d-b\"><\/i><i class=\"d-t\"><\/i><i class=\"d-y\"><\/i><i class=\"d-b\"><\/i><\/span><span class=\"yk-dots\" aria-hidden=\"true\"><i class=\"d-b\"><\/i><i class=\"d-b\"><\/i><i class=\"d-y\"><\/i><\/span><\/span><\/div><p class=\"yk-k\"><span>On the pack<\/span><\/p><div class=\"yk-c yk-c--y\">Each name can be listed<\/div><div class=\"yk-c yk-c--k\">No fixed list to print<\/div><p class=\"yk-k\"><span>Afterwards<\/span><\/p><div class=\"yk-c yk-c--y\">The powder is used up<\/div><div class=\"yk-c yk-c--k\">The grains go into fresh milk again<\/div>\n<div class=\"yk-f yk-f--y\"><img loading=\"lazy\" src=\"\/wp-content\/plugins\/kefir-link-storefront\/assets\/grain3d\/yk-cup.webp\" width=\"320\" height=\"320\" alt=\"A cup of plain yogurt\" decoding=\"async\"><\/div><div class=\"yk-f yk-f--k\"><img loading=\"lazy\" src=\"\/wp-content\/plugins\/kefir-link-storefront\/assets\/grain3d\/yk-jar.webp\" width=\"320\" height=\"320\" alt=\"A jar of kefir with grains inside and an arrow showing the grains are used again\" decoding=\"async\"><\/div>\n<\/div>\n\n<h2 id=\"species\">Species and strains are two different things<\/h2>\n<p>A species is a kind, like \u201cmango\u201d. A strain is one variety inside that kind, like Irwin and Jinhuang mangoes: both are mangoes, and they taste different.<\/p>\n<p>A probiotic capsule is like a box of Irwin mangoes: a few chosen varieties, so each name and code can be printed. Kefir grains are like an old orchard with many kinds of fruit trees, where no two harvests are quite the same.<\/p>\n\n<h2 id=\"research\">Which bacteria and yeasts do researchers find in kefir grains?<\/h2>\n<p class=\"k10-note\">This list comes from published research on kefir grains from many countries. It is not a test of our own grains. We have not sequenced them.<\/p>\n<figure class=\"hc\">\n<p class=\"hc-title\">How many kinds live in kefir? It depends on how you count.<\/p>\n<ol class=\"hc-rows\"><li><b class=\"hc-v hc--one\">7<\/b><p class=\"hc-l\">kinds grown in the lab from grains collected in Taiwan: 4 bacteria and 3 yeasts<\/p><span class=\"hc-track\" aria-hidden=\"true\"><i class=\"hc-dot hc--one\" style=\"left:28.2%\"><\/i><\/span><p class=\"hc-s\"><a href=\"https:\/\/scholars.lib.ntu.edu.tw\/entities\/publication\/4f7482d8-156f-45fd-b8c3-66b682855874\" rel=\"noopener\" target=\"_blank\">Chen, 2008<\/a>; <a href=\"https:\/\/scholars.lib.ntu.edu.tw\/handle\/123456789\/725551\" rel=\"noopener\" target=\"_blank\">Wang, 2011<\/a><\/p><\/li><li><b class=\"hc-v hc--one\">24\u201356<\/b><p class=\"hc-l\">kinds of bacteria in one grain, told apart by their DNA<\/p><span class=\"hc-track\" aria-hidden=\"true\"><i class=\"hc-bar hc--one\" style=\"left:46.0%;width:12.3%\"><\/i><\/span><p class=\"hc-s\"><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC3716650\/\" rel=\"noopener\" target=\"_blank\">Marsh, 2013<\/a>, counted by <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC4854945\/\" rel=\"noopener\" target=\"_blank\">Bourrie, 2016<\/a><\/p><\/li><li><b class=\"hc-v hc--one\">30\u201350<\/b><p class=\"hc-l\">species of bacteria and yeasts living together in one kefir<\/p><span class=\"hc-track\" aria-hidden=\"true\"><i class=\"hc-bar hc--one\" style=\"left:49.2%;width:7.4%\"><\/i><\/span><p class=\"hc-s\"><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC7610452\/\" rel=\"noopener\" target=\"_blank\">Blasche, 2021<\/a><\/p><\/li><li><b class=\"hc-v hc--all\">50+<\/b><p class=\"hc-l\">species found across all the grains studied so far<\/p><span class=\"hc-track\" aria-hidden=\"true\"><i class=\"hc-dot hc--all\" style=\"left:56.6%\"><\/i><\/span><p class=\"hc-s\"><a href=\"https:\/\/hrcak.srce.hr\/file\/144662\" rel=\"noopener\" target=\"_blank\">Poga\u010di\u0107, 2013<\/a><\/p><\/li><li><b class=\"hc-v hc--all\">861<\/b><p class=\"hc-l\">strains of 15 kinds of bacteria, in kefir made from 64 grains from 25 countries<\/p><span class=\"hc-track\" aria-hidden=\"true\"><i class=\"hc-dot hc--all\" style=\"left:97.8%\"><\/i><\/span><p class=\"hc-s\"><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10568436\/\" rel=\"noopener\" target=\"_blank\">Walsh, 2023<\/a><\/p><\/li><\/ol>\n<div class=\"hc-axis\" aria-hidden=\"true\"><span class=\"hc-axis-in\"><span style=\"left:0.0%\">1<\/span><span style=\"left:33.3%\">10<\/span><span style=\"left:66.7%\">100<\/span><span style=\"left:100.0%\">1000<\/span><\/span><\/div>\n<p class=\"hc-key\"><span class=\"hc-k hc--one\">in one grain or one kefir<\/span><span class=\"hc-k hc--all\">across many grains<\/span><\/p>\n<figcaption>Growing microbes in the lab finds fewer kinds than reading their DNA, because many grow poorly alone. Inside one kefir, each species was usually present as one main strain <span class=\"k10-cite\">(<a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10568436\/\" rel=\"noopener\" target=\"_blank\">Walsh, 2023<\/a>)<\/span>. The scale goes up in steps of ten.<\/figcaption>\n<\/figure>\n<div class=\"ww\">\n<section class=\"ww-g ww-g--lab\"><p class=\"ww-h\"><span class=\"ww-mk\" aria-hidden=\"true\"><\/span>Lactic acid bacteria <span>make kefir sour and set the milk<\/span><\/p><ul class=\"ww-list\"><li><p class=\"ww-n\"><i>Lactobacillus kefiranofaciens<\/i> <span class=\"ww-tw\">also in Taiwanese grains<\/span><\/p><p class=\"ww-one\">The main bacterium of the grain. It grows poorly on its own.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>long rods<\/dd><\/div><div><dt>Lives<\/dt><dd>mostly in the grain<\/dd><\/div><div><dt>Makes<\/dt><dd>lactic acid and kefiran<\/dd><\/div><div><dt>Taste<\/dt><dd>linked to fruity notes<\/dd><\/div><\/dl><\/li><li><p class=\"ww-n\"><i>Lactobacillus kefiri<\/i> <span class=\"ww-tw\">also in Taiwanese grains<\/span><\/p><p class=\"ww-one\">Helps hold the grain together as a sticky film.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>rods<\/dd><\/div><div><dt>Lives<\/dt><dd>grain and milk<\/dd><\/div><div><dt>Makes<\/dt><dd>lactic acid, a little acetic acid, gas<\/dd><\/div><\/dl><\/li><li><p class=\"ww-n\"><i>Lactococcus lactis<\/i> <span class=\"ww-tw\">also in Taiwanese grains<\/span><\/p><p class=\"ww-one\">Often the most common bacterium in the finished kefir, and one of the first to grow.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>small balls in chains<\/dd><\/div><div><dt>Lives<\/dt><dd>mostly in the milk<\/dd><\/div><div><dt>Makes<\/dt><dd>lactic acid<\/dd><\/div><\/dl><\/li><li><p class=\"ww-n\"><i>Leuconostoc mesenteroides<\/i> <span class=\"ww-tw\">also in Taiwanese grains<\/span><\/p><p class=\"ww-one\">Often becomes the most common bacterium late in the fermentation.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>round cells<\/dd><\/div><div><dt>Lives<\/dt><dd>mostly in the milk<\/dd><\/div><div><dt>Makes<\/dt><dd>acid and gas<\/dd><\/div><div><dt>Taste<\/dt><dd>buttery<\/dd><\/div><\/dl><\/li><\/ul><p class=\"ww-some\"><b>Found in some grains:<\/b> Lactobacillus helveticus, Lacticaseibacillus paracasei, Lactiplantibacillus plantarum, Lactobacillus acidophilus, Streptococcus thermophilus.<\/p><\/section>\n<section class=\"ww-g ww-g--yeast\"><p class=\"ww-h\"><span class=\"ww-mk\" aria-hidden=\"true\"><\/span>Yeasts <span>make the fizz<\/span><\/p><ul class=\"ww-list\"><li><p class=\"ww-n\"><i>Kluyveromyces marxianus<\/i> <span class=\"ww-tw\">also in Taiwanese grains<\/span><\/p><p class=\"ww-one\">The main yeast in the grains studied in Taiwan.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>oval cells<\/dd><\/div><div><dt>Milk sugar<\/dt><dd>can use it<\/dd><\/div><div><dt>Makes<\/dt><dd>gas and a little alcohol<\/dd><\/div><\/dl><\/li><li><p class=\"ww-n\"><i>Saccharomyces cerevisiae<\/i><\/p><p class=\"ww-one\">The same species as baker\u2019s yeast. It lives on what the bacteria leave.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>oval, budding cells<\/dd><\/div><div><dt>Milk sugar<\/dt><dd>cannot use it<\/dd><\/div><div><dt>Makes<\/dt><dd>gas and a little alcohol<\/dd><\/div><div><dt>Taste<\/dt><dd>fruity, yeasty<\/dd><\/div><\/dl><\/li><li><p class=\"ww-n\"><i>Kazachstania unispora<\/i><\/p><p class=\"ww-one\">The most common yeast in grains from 8 countries.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>oval cells<\/dd><\/div><div><dt>Milk sugar<\/dt><dd>cannot use it<\/dd><\/div><\/dl><\/li><li><p class=\"ww-n\"><i>Kazachstania turicensis<\/i> <span class=\"ww-tw\">also in Taiwanese grains<\/span><\/p><p class=\"ww-one\">Thought to help new grains form, by clumping together with Lactobacillus kefiranofaciens.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>oval cells<\/dd><\/div><\/dl><\/li><\/ul><p class=\"ww-some\"><b>Found in some grains:<\/b> Kazachstania exigua, Pichia fermentans.<\/p><\/section>\n<section class=\"ww-g ww-g--aab\"><p class=\"ww-h\"><span class=\"ww-mk\" aria-hidden=\"true\"><\/span>Acetic acid bacteria <span>add a light vinegar-like tang<\/span><\/p><ul class=\"ww-list\"><li><p class=\"ww-n\"><i>Acetobacter<\/i><\/p><p class=\"ww-one\">Common in grains, but missing from some.<\/p><dl class=\"ww-f\"><div><dt>Shape<\/dt><dd>short rods<\/dd><\/div><div><dt>Makes<\/dt><dd>acetic acid<\/dd><\/div><div><dt>Taste<\/dt><dd>vinegar-like<\/dd><\/div><\/dl><\/li><\/ul><p class=\"ww-some\"><b>Found in some grains:<\/b> Gluconobacter.<\/p><\/section>\n<div class=\"ww-asked\"><p class=\"ww-ah\">Bacteria people often ask about<\/p><ul><li><i>Lacticaseibacillus rhamnosus<\/i>: found in kefir grains in one study<\/li><li><i>Limosilactobacillus reuteri<\/i>: one study<\/li><li><i>Bifidobacteria<\/i>: only traces of DNA, never grown from kefir<\/li><li><i>Lactobacillus acidophilus, Streptococcus thermophilus, Lactobacillus bulgaricus<\/i>: a few studies, in some grains<\/li><\/ul><\/div>\n<p class=\"ww-src\">Sources: <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC4854945\/\" rel=\"noopener\" target=\"_blank\">Bourrie, 2016<\/a>, <a href=\"https:\/\/www.frontiersin.org\/journals\/microbiology\/articles\/10.3389\/fmicb.2015.01177\/full\" rel=\"noopener\" target=\"_blank\">Prado, 2015<\/a>, <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC8540521\/\" rel=\"noopener\" target=\"_blank\">Georgalaki, 2021<\/a>, <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC7610452\/\" rel=\"noopener\" target=\"_blank\">Blasche, 2021<\/a>, <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC5080400\/\" rel=\"noopener\" target=\"_blank\">Walsh, 2016<\/a>, <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC3716650\/\" rel=\"noopener\" target=\"_blank\">Marsh, 2013<\/a>, <a href=\"https:\/\/www.fao.org\/input\/download\/standards\/400\/CXS_243e.pdf\" rel=\"noopener\" target=\"_blank\">Codex<\/a> and <a href=\"https:\/\/scholars.lib.ntu.edu.tw\/handle\/123456789\/725551\" rel=\"noopener\" target=\"_blank\">Wang, 2011<\/a>.<\/p>\n<\/div>\n\n<h2 id=\"tests\">What do we check?<\/h2>\n<p>The mix of microbes shifts a little from batch to batch. These are the things we measure.<\/p>\n<ul class=\"k10-points\">\n<li><strong>How many live bacteria.<\/strong> In April 2024 SGS counted 57 billion live lactic acid bacteria in 100 g of our milk kefir. The national standard for fermented milk, CNS 3058, asks for at least 10 million per millilitre. Ours is 57 times that.<\/li>\n<li><strong>Safety.<\/strong> The same report tested for Salmonella, Listeria and the toxins of Staphylococcus aureus. All three were negative.<\/li>\n<li><strong>Every day.<\/strong> Our kefir is made in a professional food factory in Taiwan under strict hygiene control, and the acidity (pH) of every batch is measured.<\/li>\n<\/ul>\n<figure class=\"k10-fig k10-fig--doc\"><a href=\"\/en\/food-test-report\/\"><img loading=\"lazy\" src=\"\/wp-content\/uploads\/2026\/10\/sgs-milk-kefir-pathogens-report-en-768x768.png\" width=\"768\" height=\"768\" alt=\"SGS Taiwan test report AFA24404193 for our milk kefir: Salmonella, Listeria and Staphylococcus aureus enterotoxins negative, lactic acid bacteria 5.7 \u00d7 10\u2078 CFU\/g\" decoding=\"async\"><\/a><figcaption>SGS Taiwan report AFA24404193 on our milk kefir, 24 April 2024. English reference translation; the original report is in Chinese.<\/figcaption><\/figure>\n\n<div class=\"k10-banner\"><div><p class=\"k10-banner-title\">Looking for one particular strain?<\/p><p>Kefir is a food with a whole community, so it cannot promise one named strain. For that, a probiotic that prints the strain and its code on the pack can go alongside your daily glass of kefir.<\/p><p class=\"k10-ctas\"><a class=\"k10-btn k10-btn--yellow\" href=\"\/en\/product\/milk-kefir-original\/\">See our milk kefir<\/a><a class=\"k10-btn k10-btn--ghost\" href=\"https:\/\/lin.ee\/ZI19qB8\" rel=\"noopener\" target=\"_blank\">Ask us on LINE<\/a><\/p><\/div><\/div>\n\n<section class=\"k10-endcta\">\n<p class=\"k10-endcta-title\">Take the living grains home.<\/p>\n<p>Living kefir grains can ferment fresh milk in your own kitchen too, batch after batch. They come with a printed care guide.<\/p>\n<p class=\"k10-ctas\"><a class=\"k10-btn k10-btn--yellow\" href=\"\/en\/product\/kefir-grains\/\">See live kefir grains<\/a><a class=\"k10-btn k10-btn--ghost\" href=\"\/en\/kefir-grains-101-size-shape-and-color\/\">Kefir grains 101<\/a><\/p>\n<\/section>\n\n<h2 id=\"faq\">Questions customers ask us<\/h2>\n<div class=\"k10-faq\" itemscope itemtype=\"https:\/\/schema.org\/FAQPage\">\n<details class=\"k10-faq-item\" itemprop=\"mainEntity\" itemscope itemtype=\"https:\/\/schema.org\/Question\" open><summary><h3 class=\"k10-faq-q\" itemprop=\"name\">Which bacteria are in kefir?<\/h3><span class=\"k10-faq-icon\" aria-hidden=\"true\"><\/span><\/summary><div class=\"k10-faq-a\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\"><div itemprop=\"text\"><p>Mostly lactic acid bacteria and yeasts, with a few acetic acid bacteria. They live together in the kefir grains. The species researchers have named are in <a href=\"#research\">What researchers find<\/a>.<\/p><\/div><\/div><\/details>\n<details class=\"k10-faq-item\" itemprop=\"mainEntity\" itemscope itemtype=\"https:\/\/schema.org\/Question\"><summary><h3 class=\"k10-faq-q\" itemprop=\"name\">Why does the bottle have no strain list?<\/h3><span class=\"k10-faq-icon\" aria-hidden=\"true\"><\/span><\/summary><div class=\"k10-faq-a\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\"><div itemprop=\"text\"><p>Kefir is fermented by a whole living community, and its mix shifts a little with every batch. Yogurt uses a few fixed bacteria, so they can be listed one by one.<\/p><\/div><\/div><\/details>\n<details class=\"k10-faq-item\" itemprop=\"mainEntity\" itemscope itemtype=\"https:\/\/schema.org\/Question\"><summary><h3 class=\"k10-faq-q\" itemprop=\"name\">Does it contain <i>Lactobacillus rhamnosus<\/i> or another particular strain?<\/h3><span class=\"k10-faq-icon\" aria-hidden=\"true\"><\/span><\/summary><div class=\"k10-faq-a\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\"><div itemprop=\"text\"><p>Kefir grains have their own bacteria, led by <i>Lactobacillus kefiranofaciens<\/i>. Bacteria known from capsules, such as <i>Lacticaseibacillus rhamnosus<\/i>, have been reported in kefir grains in a single study <span class=\"k10-cite\">(<a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC4854945\/\" rel=\"noopener\" target=\"_blank\">Bourrie and colleagues, 2016<\/a>)<\/span>. If you are looking for one particular strain, choose a product that prints that strain on the pack.<\/p><\/div><\/div><\/details>\n<details class=\"k10-faq-item\" itemprop=\"mainEntity\" itemscope itemtype=\"https:\/\/schema.org\/Question\"><summary><h3 class=\"k10-faq-q\" itemprop=\"name\">With no strain list, how do I know there are live bacteria in it?<\/h3><span class=\"k10-faq-icon\" aria-hidden=\"true\"><\/span><\/summary><div class=\"k10-faq-a\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\"><div itemprop=\"text\"><p>In April 2024 SGS counted 57 billion live lactic acid bacteria in 100 g of our milk kefir. The soft hiss when you open the bottle and the fine fizz in the glass also show that the yeasts are still at work.<\/p><\/div><\/div><\/details>\n<details class=\"k10-faq-item\" itemprop=\"mainEntity\" itemscope itemtype=\"https:\/\/schema.org\/Question\"><summary><h3 class=\"k10-faq-q\" itemprop=\"name\">Kefir is thinner than yogurt. Does it have fewer bacteria?<\/h3><span class=\"k10-faq-icon\" aria-hidden=\"true\"><\/span><\/summary><div class=\"k10-faq-a\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\"><div itemprop=\"text\"><p>No. How thick it is depends on the milk and the way it is fermented, not on how many bacteria it holds. The count our lab measured is in <a href=\"#tests\">What we check<\/a>.<\/p><\/div><\/div><\/details>\n<details class=\"k10-faq-item\" itemprop=\"mainEntity\" itemscope itemtype=\"https:\/\/schema.org\/Question\"><summary><h3 class=\"k10-faq-q\" itemprop=\"name\">Are kefir grains a powder made in a lab?<\/h3><span class=\"k10-faq-icon\" aria-hidden=\"true\"><\/span><\/summary><div class=\"k10-faq-a\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\"><div itemprop=\"text\"><p>No. Kefir grains are soft, white, springy lumps that look like small cauliflower florets. The bacteria and yeasts live inside kefiran, a gel they make themselves. The grains grow in milk, and once strained out they go into fresh milk for the next batch. In practice, new grains grow only from existing grains. More in <a href=\"#grains\">What kefir grains are<\/a>.<\/p><\/div><\/div><\/details>\n<details class=\"k10-faq-item\" itemprop=\"mainEntity\" itemscope itemtype=\"https:\/\/schema.org\/Question\"><summary><h3 class=\"k10-faq-q\" itemprop=\"name\">Does the mix change while the bottle is in the fridge?<\/h3><span class=\"k10-faq-icon\" aria-hidden=\"true\"><\/span><\/summary><div class=\"k10-faq-a\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\"><div itemprop=\"text\"><p>Only slowly. Cold slows the bacteria and yeasts right down, so the mix changes very little. The longer the bottle is kept, the more sour and fizzy the kefir gets. How temperature shifts the mix is shown in <a href=\"#taste\">Temperature and who leads<\/a>.<\/p><\/div><\/div><\/details>\n<\/div>\n<div class=\"k10-faq-more\"><p><strong>Any question?<\/strong> Just message us on LINE. We\u2019re always happy to help.<\/p><a class=\"k10-faq-line\" href=\"https:\/\/lin.ee\/ZI19qB8\" rel=\"noopener\" target=\"_blank\">Message us on LINE<\/a><\/div>\n\n<h2 id=\"papers\">Research papers behind this article<\/h2>\n<details class=\"k10-papers\"><summary>Show all 21 papers<\/summary><ul>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC4854945\/\" rel=\"noopener\" target=\"_blank\">Bourrie, Willing and Cotter, 2016, Frontiers in Microbiology<\/a><\/li>\n<li><a href=\"https:\/\/www.frontiersin.org\/journals\/microbiology\/articles\/10.3389\/fmicb.2015.01177\/full\" rel=\"noopener\" target=\"_blank\">Prado and colleagues, 2015, Frontiers in Microbiology<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC8540521\/\" rel=\"noopener\" target=\"_blank\">Georgalaki and colleagues, 2021, Microorganisms<\/a><\/li>\n<li><a href=\"https:\/\/hrcak.srce.hr\/file\/144662\" rel=\"noopener\" target=\"_blank\">Poga\u010di\u0107 and colleagues, 2013, Mljekarstvo<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC3716650\/\" rel=\"noopener\" target=\"_blank\">Marsh and colleagues, 2013, PLoS One<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10568436\/\" rel=\"noopener\" target=\"_blank\">Walsh and colleagues, 2023, iScience<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC7610452\/\" rel=\"noopener\" target=\"_blank\">Blasche and colleagues, 2021, Nature Microbiology<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC5080400\/\" rel=\"noopener\" target=\"_blank\">Walsh and colleagues, 2016, mSystems<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC3769826\/\" rel=\"noopener\" target=\"_blank\">Magalh\u00e3es and colleagues, 2011, Brazilian Journal of Microbiology<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC12053101\/\" rel=\"noopener\" target=\"_blank\">Yerlikaya and colleagues, 2025, Food Science and Nutrition<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC7466173\/\" rel=\"noopener\" target=\"_blank\">Ribeiro and colleagues, 2020, Foods<\/a><\/li>\n<li><a href=\"https:\/\/hrcak.srce.hr\/file\/270717\" rel=\"noopener\" target=\"_blank\">Baruk\u010di\u0107 and colleagues, 2017, Mljekarstvo<\/a><\/li>\n<li><a href=\"https:\/\/doi.org\/10.1016\/j.idairyj.2011.01.001\" rel=\"noopener\" target=\"_blank\">Gr\u00f8nnevik and colleagues, 2011, International Dairy Journal<\/a><\/li>\n<li><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC3833126\/\" rel=\"noopener\" target=\"_blank\">Leite and colleagues, 2013, Brazilian Journal of Microbiology<\/a><\/li>\n<li><a href=\"https:\/\/scholars.lib.ntu.edu.tw\/entities\/publication\/4f7482d8-156f-45fd-b8c3-66b682855874\" rel=\"noopener\" target=\"_blank\">Chen, Wang and Chen, 2008, Food Microbiology<\/a><\/li>\n<li><a href=\"https:\/\/scholars.lib.ntu.edu.tw\/handle\/123456789\/725551\" rel=\"noopener\" target=\"_blank\">Wang, 2011, National Taiwan University thesis<\/a><\/li>\n<li><a href=\"https:\/\/doi.org\/10.5493\/wjem.v15.i4.112191\" rel=\"noopener\" target=\"_blank\">Katchieva and colleagues, 2025, World Journal of Experimental Medicine<\/a><\/li>\n<li><a href=\"https:\/\/doi.org\/10.1016\/j.cell.2024.08.008\" rel=\"noopener\" target=\"_blank\">Liu and colleagues, 2024, Cell<\/a><\/li>\n<li><a href=\"https:\/\/www.fao.org\/input\/download\/standards\/400\/CXS_243e.pdf\" rel=\"noopener\" target=\"_blank\">Codex Alimentarius, standard for fermented milks (CXS 243-2003)<\/a><\/li>\n<li><a href=\"https:\/\/www.fao.org\/4\/a0512e\/a0512e.pdf\" rel=\"noopener\" target=\"_blank\">FAO and WHO, 2002, guidelines for the evaluation of probiotics in food<\/a><\/li>\n<li><a href=\"https:\/\/www.gov.mb.ca\/agriculture\/food-safety\/education-resources\/pubs\/fermented-kefir.pdf\" rel=\"noopener\" target=\"_blank\">BC Centre for Disease Control, 2024, fermented food guidance: kefir<\/a><\/li>\n<\/ul><\/details>\n\n<aside class=\"k10-author\">\n<img loading=\"lazy\" src=\"\/wp-content\/uploads\/2026\/10\/chef-nik-author.webp\" width=\"176\" height=\"176\" alt=\"Nik, founder of \u6771\u6b50\u56b4\u9078\uff5ckefir.link\" decoding=\"async\">\n<div>\n<p class=\"k10-author-title\">About the author<\/p>\n<p>Nik is the founder of \u6771\u6b50\u56b4\u9078\uff5ckefir.link and a former chef from Europe. He runs the company in Taiwan, develops our products, from milk, soy and water kefir to granola and kefir soap, and writes the articles on this blog. <a href=\"\/en\/about-us\/\">About us<\/a> \u00b7 <a href=\"\/en\/blog\/\">More articles<\/a><\/p>\n<\/div>\n<\/aside>\n\n<nav class=\"k10-related\" aria-label=\"Related reading\">\n<p class=\"k10-related-title\">Related reading<\/p>\n<ul>\n<li><a href=\"\/en\/kefir-grains-101-size-shape-and-color\/\">Kefir Grains 101: Size, Shape and Color<\/a><\/li>\n<li><a href=\"\/en\/10-things-you-need-to-know-about-kefir\/\">10 Things You Need to Know About Kefir<\/a><\/li>\n<li><a href=\"\/en\/how-to-make-kefir\/\">How to Make Kefir at Home: The Complete Guide<\/a><\/li>\n<\/ul>\n<\/nav>\n<p class=\"k10-float\"><span>Milk kefir, fermented with living grains<\/span><a class=\"k10-btn k10-btn--yellow\" href=\"\/en\/product\/milk-kefir-original\/\">See it<\/a><\/p>\n<\/div>\n<script>(function(){var r=document.querySelectorAll('.k10-toc a');if(!r.length||!('IntersectionObserver' in window)){return;}var o=new IntersectionObserver(function(es){es.forEach(function(e){if(e.isIntersecting){r.forEach(function(a){a.classList.toggle('is-active',a.hash==='#'+e.target.id);});}});},{rootMargin:'0px 0px -70% 0px'});document.querySelectorAll('.k10-main h2').forEach(function(h){o.observe(h);});})();<\/script>\n<script>(function(){if(!('IntersectionObserver' in window)){return;}function lazy(sel,src){var f=document.querySelector(sel);if(!f){return;}var o=new IntersectionObserver(function(es){es.forEach(function(e){if(e.isIntersecting){o.disconnect();import(src);}});},{rootMargin:'600px 0px'});o.observe(f);}lazy('figure.kg','\/wp-content\/plugins\/kefir-link-storefront\/assets\/grain3d\/grain3d.js?v=5');lazy('figure.kt','\/wp-content\/plugins\/kefir-link-storefront\/assets\/grain3d\/kt.js?v=4');})();<\/script>\n<\/div><\/trp-tag><\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>",
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        "rendered": "<p>Why a kefir bottle has no strain list, what kefir grains are, which microbes researchers find in them, and how temperature changes which ones lead.<\/p>",
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