Get to Know Your Probiotics
Eleven strains live in every bottle of Flourish. They have jobs, preferences, and in one case a genuine claim to having survived six years in outer space. Let's do introductions.
Most probiotic labels give you a list of Latin names and leave it there. That's a shame, because these organisms are genuinely interesting once you know a bit about them.
So we asked each of them to introduce themselves. A quick note on the science before they start.
Why some of these names look different from your last bottle
In 2020, a team of taxonomists did something dramatic: they split the genus Lactobacillus into 25 separate genera.1 It had grown to over 250 species that weren't especially closely related, which was making a mess of the science.
So Lactobacillus casei became Lacticaseibacillus casei, L. fermentum became Limosilactobacillus fermentum, and L. plantarum became Lactiplantibacillus plantarum. Same organisms, new surnames. We've given both below, because the old names are what most people search for.
The lactobacilli — five of them
Lactobacillus acidophilus
Goes by: L. acidophilus
Oxygen: Facultative anaerobic Shape: Rod Lives in: GI tract, mouth, vaginal tract2
I was described back around 1900, which makes me one of the longer-standing members of this group, and researchers have been picking over me ever since. My taxonomy has been revised more than once, and I have been misidentified on more product labels than I care to think about.2
Some people assume I only turn up in dairy. Not true. I'll live anywhere there's plenty of my favorite food. I produce lactic acid as I grow and I'm acid tolerant, so getting through your stomach to the lower GI tract is straightforward for me under most conditions.
Lactobacillus delbrueckii subsp. bulgaricus
Goes by: L. bulgaricus
Oxygen: Aerotolerant anaerobic Shape: Rod Lives in: GI tract2
I'm the one named after a country. In 1905, a young Bulgarian physician called Stamen Grigorov — a fourth-year medical student in Geneva at the time — worked out that I was what turned milk into Bulgarian yogurt. They named me after his homeland.3,4
You may have heard Élie Metchnikoff gets the credit. He's the one who noticed rural Bulgarians living remarkably long lives and connected it to all the fermented milk they drank — which is what made me famous. But he didn't isolate me, and by most accounts he didn't know who had.4
I ferment sugar into lactic acid when oxygen isn't available. In Flourish, that mostly means the glucose and fructose in the molasses and sorghum.
Lacticaseibacillus casei
Formerly Lactobacillus casei. Goes by: L. casei
Oxygen: Facultative anaerobic Shape: Rod Lives in: GI and reproductive tracts5
Being facultatively anaerobic means I'm flexible: I make energy with oxygen when it's around, and switch to fermentation when it isn't. Handy, given where I end up.
My favorite fuels are glucose, fructose and sucrose — which is most of what molasses and sorghum are made of, so Flourish Original and Flourish Junior suit me nicely.5 I'm acid stable, and I produce organic acids that pathogenic bacteria don't appreciate one bit.6
Limosilactobacillus fermentum
Formerly Lactobacillus fermentum. Goes by: L. fermentum
Oxygen: Facultative anaerobic Shape: Rod Lives in: Mouth, GI tract, colon, vaginal tract
My cousin Limosilactobacillus reuteri and I are so closely related that we were originally thought to be the same organism. Awkward for a while.
I turn up in human breast milk, among other places.7 As a lactic acid producer, the useful thing I do is take up space and resources that less friendly bacteria would otherwise be using.
Lactiplantibacillus plantarum
Formerly Lactobacillus plantarum. Goes by: L. plantarum
Oxygen: Facultative anaerobic Shape: Rod Lives in: GI tract, saliva8
I'm the adaptable one. I grow across a wide range of environments, temperatures and pH levels, which is why you'll find me from the top of the GI tract to the bottom.8
I'm also transient by nature — I don't stay in one place long.9 If you've eaten sauerkraut, sourdough, kimchi or almost any fermented vegetable, you've eaten me.10
The bifidobacteria — two of them
Bifidobacterium bifidum
Goes by: B. bifidum
Oxygen: Anaerobic Shape: Branched rod Lives in: GI tract
I'm typically the most common species in breastfed babies, followed by my colleagues B. breve and B. longum. My numbers tend to fall off considerably as people age, which is a bit rude.
Researchers have found that healthy people tend to have a lot of me in their guts. Some of that may come down to my relationship with mucin — the lining of the gut.11 We're better together.
Bifidobacterium longum
Goes by: B. longum
Oxygen: Anaerobic Shape: Branched rod Lives in: GI and vaginal tracts12
Like B. bifidum, I'm among the most common species in breastfed babies, and I also decline naturally with age.11
We're both lactic acid producers, which keeps the gut unfriendly to pathogens while staying hospitable to other beneficial bacteria. I make my living on the dietary fibers your own enzymes can't break down, plus the glycans your gut cells produce — which is a polite way of saying I eat things you can't.13
The round ones — two cocci
Everyone above is rod-shaped. These two are spheres — and unlike the groups either side of them, they aren't close relatives. They just happen to look alike and do similar work.
Enterococcus lactis
Goes by: E. lactis
Oxygen: Facultative anaerobic Shape: Coccus (sphere or oval) Lives in: GI tract, fermented dairy
I was first isolated from Italian raw milk cheese.14,15 As a lactic acid producer, I'm known for what I contribute to a cheese's taste, smell and texture — a nicer job description than most bacteria get.
I'm also durable, holding up across a wide range of pH and temperature. Like several of my colleagues, I respire aerobically when oxygen is around and switch to fermentation when it isn't.
Streptococcus thermophilus
Goes by: S. thermophilus
Oxygen: Facultative anaerobic Shape: Coccus (sphere or oval) Lives in: Fermented dairy, transiently in the GI tract
If you've eaten yogurt, you've eaten me — I'm one half of the classic yogurt pair, alongside L. bulgaricus a few cards up. Microbiologists have a word for what we do together: protocooperation. I supply formic acid, folic acid and carbon dioxide that speed his growth along; he's far better at breaking down protein, so he hands back peptides and amino acids I can't make enough of myself.16,17
My name means heat-loving, and I earn it — I grow best around 35–42°C, warmer than most of this group prefers.16
Neither of us needs the other to survive. We are simply much faster together, which is rather the point of this whole bottle.
The yeast — the one that isn't a bacterium
Saccharomyces cerevisiae
Goes by: Brewer's yeast
Oxygen: Prefers it, manages without Shape: Typically spherical Lives in: Respiratory, GI and urinary tracts18
I'm the odd one out. I'm a single-celled, non-spore-forming fungus — not a bacterium at all. All my colleagues here are prokaryotes, meaning their cells and DNA are arranged rather differently from eukaryotes like me. And plants. And you.
You know me already: I'm what makes beer beer and bread rise. One of the more useful things I do here is make the environment inhospitable to less friendly molds.18
The spore-former — and the space record
Bacillus subtilis
Goes by: B. subtilis
Oxygen: Facultative anaerobic, prefers oxygen19 Shape: Rod Lives in: GI tract
I have strong opinions about temperature. So strong that when conditions aren't to my liking, I form an endospore — essentially folding in on myself inside a tough outer shell and waiting it out.
That skill has taken me places. Spores of mine spent nearly six years bolted to the outside of NASA's Long Duration Exposure Facility in low Earth orbit. Shielded from solar UV, up to 80% of us survived.20,21 Not to brag.
Back on Earth I also work as a fungicide and help promote root growth in plants.19 I keep busy.
Why they're grown together
That's the gang. Eleven strains, and the thing that makes them work is that they were never introduced as strangers.
In conventional probiotic manufacturing each strain is grown separately, freeze-dried, and combined as powder at the end — so the first time they meet is inside a capsule. In the Flourish Way, they grow up together in one ferment, in the same liquid, sharing the same food.
They get along. Several of them make organic acids that lower the pH of the environment, which suits the others and doesn't suit pathogens — one of several ways beneficial bacteria earn their keep.6
And because we never freeze-dry them, they arrive in the liquid they made themselves — still alive, still working.
Flourish is a dietary supplement made to support digestive and microbiome health. It isn't a treatment for any condition. Probiotic effects are strain-specific, and information about an organism isn't a claim about what any product does. Check with your doctor before starting a new supplement, and with your pediatrician before giving one to a child.
Thanks for taking the time to get to know the friendly gang of Flourish living probiotics.
Ready to try a living probiotic?
Eleven living strains. One daily shot. For the whole family.
Shop Flourish Original · Shop Flourish Junior · Why we keep it liquid
A few questions we hear a lot
Why do some probiotic names keep changing?
Because genome sequencing revealed that the genus Lactobacillus had become a catch-all for organisms that weren't closely related. In 2020 it was split into 25 genera.1 The organisms didn't change — only what we call them.
Is a yeast really a probiotic?
Yes. The definition is about live microorganisms conferring a health benefit, not about being a bacterium. Saccharomyces is a fungus, and it's the reason the group is described as microorganisms rather than bacteria.
Do more strains mean a better probiotic?
Not automatically, and we won't pretend otherwise. Probiotic effects are strain-specific, and a large number on a label doesn't guarantee anything by itself. What we'd argue matters here is that ours are grown together as a community rather than blended as powders.
What does "facultative anaerobic" actually mean?
It means the organism makes energy with oxygen when oxygen is available, and switches to fermentation when it isn't. Useful flexibility for something heading into a colon.
Which strains are in Flourish Junior?
The same eleven. Original and Junior differ only in what they ferment on — molasses versus sorghum — which changes the taste, not the strains. It's a flavor choice, not an age one.
Do these bacteria stay in my gut?
Mostly no. Most probiotics are transient and pass through rather than colonizing permanently, which is why taking one consistently matters more than any single dose.
About this article
Written by: Lorilyn Van Dyke, Entegro Health | Originally published: October 2020
Important information
This article is for general education and isn't a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified health provider with any questions regarding a medical condition, and before starting a new supplement. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Sources
- Zheng, J., Wittouck, S., Salvetti, E., et al. (2020). A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae. International Journal of Systematic and Evolutionary Microbiology, 70(4), 2782–2858. Source
- Bull, M., Plummer, S., Marchesi, J., & Mahenthiralingam, E. (2013). The life history of Lactobacillus acidophilus as a probiotic: a tale of revisionary taxonomy, misidentification and commercial success. FEMS Microbiology Letters, 349(2), 77–87. Source
- Stamen Grigorov — discovery of Lactobacillus bulgaricus, 1905, in the laboratory of Professor Léon Massol, Geneva. Source
- LB Bulgaricum. History of Bulgarian Yoghurt — Grigorov's 1905 publication in Revue Médicale de la Suisse Romande, confirmed by Metchnikoff three years later. Source
- BacMap Genome Atlas — Lactobacillus casei. Source
- Bermudez-Brito, M., Plaza-Díaz, J., Muñoz-Quezada, S., Gómez-Llorente, C., & Gil, A. (2012). Probiotic mechanisms of action. Annals of Nutrition and Metabolism, 61(2), 160–174. Source
- BacMap Genome Atlas — Lactobacillus fermentum. Source
- BacMap Genome Atlas — Lactobacillus plantarum. Source
- Transient nature of L. plantarum in the gastrointestinal tract. NCBI PMC4705246. Source
- MicrobeWiki — Lactobacillus plantarum in fermented foods. Source
- O'Callaghan, A., & van Sinderen, D. Bifidobacteria and their role as members of the human gut microbiota. NCBI PMC4140077. Source
- MicrobeWiki — Bifidobacterium longum. Source
- BacMap Genome Atlas — Bifidobacterium longum. Source
- BacDive — Enterococcus lactis, strain record 5362. Source
- Morandi, S., et al. Journal of Dairy Science — enterococci in raw milk cheeses. Source
- Streptococcus thermophilus — growth range and synergy with L. bulgaricus in yogurt fermentation. Source
- Sieuwerts, S., Molenaar, D., van Hijum, S. A. F. T., et al. (2010). Mixed-culture transcriptome analysis reveals the molecular basis of mixed-culture growth in Streptococcus thermophilus and Lactobacillus bulgaricus. Applied and Environmental Microbiology, 76(23), 7775–7784. Source
- Fleet, G. H. (2003). Saccharomyces and related genera, Chapter 11, in: Food Spoilage Microorganisms. Boekhout T, Robert V (eds), Behr's Verlag Hamburg, pp. 306–335.
- Wickham Laboratories. Fact sheet: Bacillus subtilis. Source
- Horneck, G., Bücker, H., & Reitz, G. (1994). Long-term survival of bacterial spores in space. Advances in Space Research, 14(10), 41–45. Source
- MicrobeWiki — Bacillus subtilis. Source
