If you are familiar with the different delivery forms of probiotic products, or even simply with expiration dates, you may be concerned with something called shelf stability. Some products require special conditions for stability, often to the effect of high potency or efficacy. Others are more stable but less viable. But what’s the difference?
What makes a product stable?
The journey from production to shelf is a long and arduous journey for Lactobacillus and friends. A strain developed for commercial use is derived from an organism and multiplied. The resulting mountain of material is then tested thoroughly via different indicators of quality, one of the most important being stability. Among the most important criteria are the ability of a strain to travel through the gastrointestinal tract without breaking down (viability), and low water activity, which reduces the growth of other microorganisms. Before installation in the product you will acquire, the appropriate strain is deemed “stable” with a certificate from the manufacturer, like the one you see here:
Why is stability important?
Although an “unstable” probiotic product is certainly not on the same scale as an “unstable” nuclear power plant, if you are buying a product then it should always be up to par in this regard! According to the Office of Dietary Supplements, “Many probiotic strains derive from species with a long history of safe use in foods or from microorganisms that colonize healthy gastrointestinal tracts.” Thus, if you take an expired probiotic supplement, you will not experience any unfavorable side effects as you would when eating food past its expiration date. Once a probiotic becomes expired or unstable, it simply has broken down¬ to the point where it will not perform the mechanistic action in your body to achieve the desired supplementary effect.
Stability is measured by the amount of live organisms (or “efficable” organisms) present in the product. The population of efficable organisms in turn is affected by “thermostability,” the ability of an organism to live within a certain temperature range. Certain formulations of probiotic material can result in longer shelf lives than others. For example, a patent filed in 2003 proposed that monovalent alginate salts and encapsulation were desirableStability is measured by the amount of live organisms (or “efficable” organisms) present in the product. The population of efficable organisms in turn is affected by “thermostability,” the ability of an organism to live within a certain temperature range. Certain formulations of probiotic material can result in longer shelf lives than others. For example, a patent filed in 2003 proposed that monovalent alginate salts and encapsulation were desirable methods of preserving a probiotic with minimal water activity. Generally, however, probiotic organisms begin to die above 10 degrees Celsius.
The average shelf life of a probiotic organism is a few months long. This can depend on its method of preservation, however, and whether or not the organism is actually alive. Different modes of ensuring stability in a probiotic include freezing, freeze drying, microencapsulation, vacuum drying, and more. These methods, although important for preservation, can damage the membranes, nucleic acids and enzymes in the bacteria—thus, live organisms protected either by low temperatures or an extracellular coating are best for efficacy, if at the small cost of keeping them in a special storage environment (usually, a refrigerator). Additionally, Soil-Based Organisms (SBOs), because they are not live but are spores, are inherently stable, but confer fewer health benefits on the host because they are not “active” organisms.
How do you know if a product is stable?
Because a probiotic supplement is made to account for some natural breakdown, you can be sure for the most part that the product is at least as potent as its label lists, up until the date of expiration. There is no general threshold of concentration to be met for a strain to have an effect in the body—this varies by strain. However, there is a general range of safety and effectiveness, as this study explores. Thus, the expiration date is decided with a surplus calculated by the amount of viable probiotics up until that day. Some products can see a daily population decline between 5 and 15%!
If you consider your probiotic supplement to be crucial in maintaining a healthy lifestyle, make sure you are getting a probiotic with plenty of time cushioning its expiration, as well as a properly efficable strain! An expired or “unstable” probiotic, although not something worth worrying excessively about, will not offer the sufficient gut support you want and need.