I recently received this question:
Hi, I’ve got a quick question. Regarding greens powders,I’ve noticed that lots of greens products contain probiotics in powdered form. Now I thought that beneficial bacteria andprobiotics are highly unstable or oxidative when exposed to air,light etc. So what is logic behind adding them to powdered mixtures. Are they completely worthless this way? Thanks in advance, Sorry for possible grammar errors, Best regards, Zeljko
Zeljko…..great question! One of the best benefits of running a boutique company that uses the internet for distribution is that you tend to attract smart customers who ask questions like these.
With regards to your inquiry, you’re right that probiotic bacteria can degrade very easily in harsh environments, and if no care is given to them when they’re grown then they could be completely worthless by the time they’re put into food.
However there are a variety of techniques used when growing probiotics that allow them to have a stable shelf life before and after they’re opened, although it’s inevitable that some will die off the older the product is.
How Probiotics Are Made
To be clear, probiotics are healthy bacteria that live in your intestine and help your body fight sickness, improve circulation, and a variety of other physiological functions. They have a lot of health benefits.
The process of growing bacteria and making them suitable for human consumption is a fairly complex process that involves control over a number of different variables. The diagram below illustrates the point very well:
Most probiotic products are either suspended in a liquid like milk or powderized. I’m going to be talking about the powderized probiotics since they’re what go into greens powders and most other non-dairy probiotic supplements.
When you make a powderized probiotic the process more or less goes like this:
1). You grow and ferment the bacteria. The medium used to grow these bacteria typically involve milk or dairy ingredients but more and more are being done with a dairy free medium. They’re typically grown anywhere from 15h to 7 days.
2). You centrifuge the mixture to separate the bacteria. A centrifuge is like a turbo-charged titl-a-whirl machine you use to separate microscopic particles based on their weight. It separates the bacteria from the food molecules it was feeding on.
3). You freeze dry the bacteria and evaporate the remaining water. This is done in tightly controlled conditions in a lab so that no outside moisture or oxygen contacts the bacteria. When you’re finished with this step you have a dry, powdery batch of bacteria with a high degree of purity.
Here’s a decent video which briefly describes how the process works:
This process is usually done by a company that exclusively works with bacteria which then sells its probiotics to the supplement manufacturer that wants to use them in its products.
The Problems With Making Probiotics
This process all by itself has a lot of problems. Bacteria are sensitive creatures and they easily die in harsh conditions. Most of them would die during this process without additional modifications. When making probiotics you have the following issues to deal with:
- Sudden freezing causes damage to cell walls and intercellular structures.
- Oxygen and moisture cause bacteria to go rancid….you have to keep them contained.
- Most bacteria won’t make it into your intestine when digested. They’ll be degraded in your acidic stomach.
What are they?
- Coat the bacteria with a “cryoprotectant” before freezing. A cryoprotectant is a substance that protects cells in harsh temperatures. In the case of bacteria sucrose (sugar) is remarkably effective.
- Freeze drying itself protects the bacteria from moisture and oxygen. If a bacteria is freeze dried immediately after incubation and then stored in controlled conditions exposure to the outside environment will be minimal.
- Store bacteria with vitamin C and prebiotic fibers. Vitamin C protects most probiotic bacteria from oxidation, and soluble fibers like apple pectin and/or chicory root provide a stable medium for bacteria to subsist in that allows them to slowly replace themselves while in containment and less susceptible to environmental conditions.
- Mix the probiotics with digestive enzymes when adding them to a supplement. Digestive enzymes, particularly pepsin, help shield bacteria from the harsh conditions of the stomach and allow them to make their way into the gut.
Together these steps have a pretty dramatic effect. To illustrate my point here’s a chart that shows the survival rate of bacteria with the following treatments:
And here’s another graph showing how this same technique affects the survival rate of the bacteria:
These graphs came from a paper published in the journal Process Biochemistry.
That effect demonstrates the viability of one method. Using others has an additive effect. For example, a study published in the journal Food Research International found that storing probiotic bacteria with a prebiotic fiber increased viability by 420%.
When you put all this together powdered probiotic bacteria maintain their cell count by about 90-95% for 6 months to 1 year when they’re packaged and about 1-3 months after they’ve been opened up.
So adding probiotics into a greens powder or other powdered supplement isn’t a waste of time, even though it might seem that way at first glance. However once you open the bottle it is inevitable that the density of the probiotics will start to go down due to exposure to moisture and oxygen.
Tips For Buying Probiotic Supplements
If you’re buying a greens powder with probiotics you want to get one that has digestive enzymes and soluble fiber. Possible ingredients include apple fiber, pectin, chicory root, jerusalem artichoke, or marshmallow root, among others. My supplement guide for fiber covers your options in detail.
If you’re buying a regular probiotic supplement then I’d recommend the following advice:
- Buy a powder, not a tablet or gel
- Make sure it comes packaged with a prebiotic fiber and digestive enzymes
- Make sure it’s encapsulated….this helps prevent degradation.
- The most important number to pay attention to is the amount of Colony Forming Units (C.F.U.). This is the number of bacteria that’s expected to colonize in your intestine and start reproducing.
Addendum: If you want to get a little more technical and study this topic in depth, I’d highly recommend this paper by Maria Saarela. It describes the details of the process very well.
Research and References
1). Saarela, M. et. al. “Influence of fermentation time, cryoprotectant and neutralization of cell concentrate on freeze-drying survival, storage stability, and acid and bile exposure of Bifidobacterium animalis ssp. lactis cells produced without milk-based ingredients”
Kurtmann, Lone, et. al. “Storage stability of freeze–dried Lactobacillus acidophilus (La-5) in relation to water activity and presence of oxygen and ascorbate”
Saarela, Maria, et. al. “Fibres as carriers for Lactobacillus rhamnosus during freeze-drying and storage in apple juice and chocolate-coated breakfast cereals”
Zayed, Gaber, et. al. “Influence of trehalose and moisture content on survival ofLactobacillus salivarius subjected to freeze-drying and storage”
Capela, P., et. al. “Effect of cryoprotectants, prebiotics and microencapsulation on survival of probiotic organisms in yoghurt and freeze-dried yoghurt”
Crowe, John, et. al. “The Trehalose Myth Revisited: Introduction to a Symposium on Stabilization of Cells in the Dry State”