Formulation and Packaging for Shelf Stable Probiotics
By Terry Coyle, Chief Innovation Officer, Vitaquest International
According to International Scientific Association for Probiotics and Prebiotics (ISAPP), probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.”1 Consumer demand for these probiotics is enormous. The probiotics market size was $67.8 in 2022, and expected to reach $213.1 billion by 2032, growing at a CAGR of 12.4%.2
There are many different probiotic species, most of which offer support for immune health and gut/digestive health. In addition, there are species and strains that offer other benefits such as support for weight management, cholesterol metabolism, vaginal health, sleep, and so much more. While all of this is impressive, it only has value if there is adequate potency and stability of the probiotics in question. In other words, the value is associated with shelf stable probiotics.
Factors Affecting Probiotic Viability
There are a few different factors that affect probiotic viability/stability. These include temperature and light sensitivity, pH and water activity, and oxygen and microbial Competition.
Temperature and Light Sensitivity
The International Probiotics Association reported research3 citing that high temperatures decrease the viability of some live probiotic strains, while low temperature (like refrigeration) has been reported to be better for the survival of certain probiotics.
So, should you refrigerate probiotics? Doing so may help.
USP data4 also indicates probiotics generally survive well when stored at room temperature, specifically between 68°F and 77°F, like in a temperature-controlled environment.
Likewise, probiotics are sensitive to light. More specifically, gamma or ultraviolet radiation from sunlight can inactivate probiotics.5 For this reason, the use of PET packaging offers some degree of protection against UV wavelengths present in natural light and certain types of man-made lighting.
pH and Water Activity
Moisture (water) can activate probiotics, but they will then quickly die off because they don't have access to food.6 This process should only happen after the probiotics reach the microbiome of the gut. This die-off phenomenon may occur when probiotics are formulated with other nutraceuticals that have slightly too much moisture. To avoid this, it's important to know which nutraceuticals are compatible with probiotics.
Another factor which can impact the viability of probiotics is pH. Probiotics must be able to survive in acidic environments to pass through the stomach and small intestine and reach the colon. The pH of gastric juice is around 2.0–3.0, which can kill most ingested microorganisms. Studies have found that a pH 2.0 or below is the most harmful to probiotic bacteria, while a pH of 3.0, 4.0, and 5.0 are less harmful. However, some studies have found that probiotic strains can survive at pH 2–4 for up to 2 hours.7
Oxygen and Microbial Competition
Oxygen can negatively affect the viability of probiotics. This is because high oxygen levels can cause the production of reactive oxygen species (ROS), which can damage proteins, DNA, lipids, and even cause cell death. This process is called oxidative stress.8 For this reason, probiotics should be kept in their bottles with the lids tightly sealed when not in use.
In microbial communities, competition between organisms can be exploitative or interference. Exploitative competition occurs when organisms compete for shared resources at low population densities. As population density increases and resources decrease, competition can shift to interference, where organisms may even excrete toxic chemicals into the environment to harm their competitors.9 It is possible to address exploitive competition through the inclusion of prebiotic food sources.
Formulation Strategies for Enhanced Probiotic Stability
To address these challenges, several strategies can be employed to improve probiotic stability. These include microencapsulation techniques, enhancing the probiotics' intrinsic tolerance to environmental stressors, and creating synbiotic formulations for added protection and efficacy.
Microencapsulation
In this context, the process of microencapsulation is where small probiotic particles are coated to give the microorganism protection against degradation, preventing interaction with other ingredients, and increasing stability. Fluid bed technology (such as spray coating) enables controlled application and mixing of dry components by spraying complete or partial coatings or multiple coating layers on a powders surface. The ultimate result will be a controlled release of the probiotics so that they are protected from degradation in the stomach and first part of small intestine but released further down in the intestines where they normally reside and provide their benefits.
Enhancing Intrinsic Tolerance: Building Stronger Probiotics
Another option for promoting the intrinsic tolerance of probiotics is to utilize those in the Bacillus genus, which are spore-forming. The spore is a naturally occurring protective encasement that allows the probiotic within to survive transit through the stomach and small intestine intact, retaining its potency.10
Likewise, there are other probiotic strains which tend to be more hardy and able to better withstand the destructive environment of the stomach and small intestine. An experienced contract development and manufacturing organization (CDMO), like Vitaquest, can help you identify appropriate hardy strains available for use in your probiotic supplements.
The use of “postbiotics” is also a good option. Postbiotics are probiotics that have been pasteurized or heat-treated, and yet still provide health benefits.11 Since postbiotics are not alive, they do not have the same stability issue as probiotics.
Development of Synbiotics (Probiotics + Prebiotics)
Still another option for enhancing probiotic stability is through the development of “synbiotic” formulations. Synbiotics (i.e., synergistic biotics) are a biotics combination, typically with pre-and probiotics, but may include postbiotics as well.
A synbiotic combination makes sense on a couple of levels. First, prebiotics feed and nurture probiotics, so if a probiotic is unexpectedly activated due to moisture, there will be a source of food to sustain the probiotic. Also, now that postbiotics are available, a combination of all three makes for a comprehensive approach to supporting the health of the microbiome with the three categories of biotics. Furthermore, the postbiotics don’t need to be fed, so there won’t be any competition between them and the probiotics for the prebiotic food source.
Again, an experienced CDMO can help you identify appropriate combinations of pre-, pro- and postbiotic options for use in your synbiotic supplements.
Packaging Solutions for Extending Probiotic Shelf Life
There are also probiotic packaging solutions to consider in extending shelf life. These include creating a controlled atmosphere, and light-resistant packaging.
Creating a Controlled Atmosphere: Oxygen and Moisture Barrier Solutions
There are several packaging options available that can effectively serve as barriers to oxygen and moisture:
- Desiccant lined bottles – The insides of these bottles are lined with natural desiccant polymers. Consequently, the bottles help preserve the potency of probiotics by also absorbing moisture and oxygen.
- Blister packs – The use of blister packs helps reduce probiotic exposure to oxygen and moisture, which tends to make it more likely to sustain the probiotics’ lifespan through expiration dating.
- Glass or PET bottles – Both glass and PET bottles also do a relatively good job of limiting exposure to oxygen and moisture.
- Desiccants – Desiccant packs included in a bottle during packaging can help absorb ambient moisture, keeping it away from the probiotics.
Light-Resistant Packaging for Sensitive Strains
As with oxygen and moisture, it is also important to limit probiotics’ exposure to light. The blister pack option listed above is ideal if they are kept closed in their original box. Likewise, the bottle options are also good but ensure the bottle color is opaque or slightly dark. This will help reduce the penetration of UV wavelengths present in natural light and certain types of man-made lighting.
Quality Control and Testing: Ensuring Probiotic Potency from Lab to Shelf
While quality control is important to produce all dietary supplements, it is especially important for probiotics since these are live microorganisms easily vulnerable to stability problems if not handled and stored carefully and appropriately. Of prime consideration is cGMP manufacturing and testing for viability.
cGMP Manufacturing
Current Good Manufacturing Practices (cGMPs) stipulate that proper controls are in place for dietary supplements—including probiotics—so that they are processed in a consistent manner to meet identity, purity, strength, and composition quality standards. cGMPs apply to all domestic and foreign companies that manufacture, package, label or hold dietary supplements, including those involved with the activities of testing, quality control, packaging and labeling, and distributing them in the U.S. All supplement companies are required to maintain cGMPs, and to have a program in place to audit all contract manufacturing, packaging, and distribution facilities that they use, to verify compliance with cGMPs. However, not all supplement companies are consistently compliant.
For probiotics, proper storage following cGMPs is crucial to protect them from light, moisture, and high temperatures. Hence, it is critical that your probiotic supplement be manufactured at a CDMO with experience in the storage, handling and processing of probiotics.
Testing for Viability
Probiotic potency is measured in colony forming units (CFU). Testing for CFU may be accomplished through plating or flow cytometry. Plating is a classic microbiology technique that involves spreading bacterial stock on an agar plate and counting the number of visible colonies. The number of colonies is multiplied by the dilution factor to calculate the CFU per unit volume. Flow cytometry is a rapid, culture-independent technique that uses light scattering and fluorescence to detect cells. This method can quickly provide cell count information. In either case, the determination of CFU may be completed when the probiotic material first arrives at the CDMO, as well as once the finished product is produced.
As with other types of dietary supplements, stability testing should be part of the testing protocol. However, of the two types of stability testing, only one is suitable for probiotics.
Ambient or “real time” stability is determined by taking a sample of packaged manufactured product and holding it in a retain room under controlled, ambient temperature and humidity conditions. The retain room is used to correlate and confirm shelf-life results from accelerated testing. At regular intervals during its shelf life, a product is pulled from the retain room and tested for potency. This is the type of stability testing suitable for probiotics.
Accelerated stability is when a dietary supplement in its intended packaging is placed inside an environmental chamber which controls temperature and humidity. This chamber will create temperature and humidity conditions which are designed to accelerate the normal aging of a product. Since this type of stability testing can destroy microorganisms, it is not suitable for probiotics.
Storage and Handling Best Practices for Optimal Shelf Life
There are best practices for the storage and handling of probiotics in order to achieve optimal shelf life. These include maintaining the ideal environment, first-in-first-out and overages, and educating the consumer.
Maintaining the Ideal Environment
The optimal temperature and humidity ranges for storing probiotics is vital. As previously stated, probiotic survival is generally good in a storage temperature of 68°–77° F. Some probiotics are particularly sensitive to temperature and need to be stored in the refrigerator. An experienced CDMO will be aware of required storage conditions and will know whether or not the probiotics in question can be stored in a general temperature-controlled environment or should be placed in their commercial refrigeration unit.
The ideal relative humidity for storing probiotics is below 30%. Again, an experienced CDMO will be able to accommodate this requirement.
After a brand owner takes possession of the finished probiotic product, it's crucial that warehouse storage follows the specified temperature and humidity requirements to ensure the product's stability is maintained.
After the products reach retail shelves, similar storage conditions should be maintained. In many cases, the store shelves in a temperature- and humidity-controlled environment will suffice. For more sensitive probiotic strains, refrigeration in the store may be required. The product label should provide appropriate storage directions.
First-in-First-Out and Overages: Optimizing Inventory Management
Although it is always a good practice to follow first-in-first-out (FIFO) inventory management practices to avoid product expiration and maintain quality, it is particularly important to do so with probiotics which contain live microorganisms and are more subject to degradation than other supplements.
Overages refer to adding a higher percentage of the nutraceutical than is required to meet label claim at the time of manufacture. This might range between 3% and 25% for some nutrients but tends to be even higher in the case of probiotics. The probiotic supplier can provide some guidance in this regard. In some cases, the overages may range between 25% and 100% or even higher. In other cases, the supplier’s recommended dose may already include an appropriate overage, which makes it easier for formulation purposes.
Educating the Consumer
Brand owners would be wise to provide consumers with clear and accurate information about proper storage and handling instructions on the product label or packaging. This is important because proper storage will maintain potency, which means that consumers are more likely to receive expected results. This, of course, is also more likely to result in repeat sales—a win-win for brand owners and consumers alike.
How Can Vitaquest Help in Manufacturing Shelf Stable Probiotics?
Vitaquest is the largest custom, non-originator CDMO of probiotic dietary supplements in the United States for both emerging and established brands, offering quality, transparency, and rigorous qualification. As a CDMO, Vitaquest has provided nutraceutical businesses with best-in-class probiotic supplement formulation design, contract manufacturing, packaging, testing and fulfillment services for over 45 years.
Whether you're a newcomer to the industry or aiming to diversify your product range, Vitaquest possesses the expertise, cutting-edge facilities, and solutions needed to swiftly and effectively turn your shelf stable probiotics concept into reality. Vitaquest offers a variety of dosage forms, including capsules, tablets, and powders and is one of only a few U.S.-based CDMOs to offer a full range of particle and powder engineering services utilizing fluid bed, oscillation, and roll compaction technologies.
Vitaquest also has expertise in domestic and international regulatory standards. In fact, we are GMP certified by NSF, providing assurance to brand owners and consumers alike about compliance with industry regulations and standards. In addition, Vitaquest can offer Kosher, Halal, and certified organic products, and FSSC 22000 certification for food safety.
Are you ready to move forward with creating high-quality shelf-stable probiotic supplements for your brand? If so, call 800-526-9095 to speak with one of our knowledgeable sales executives or visit Vitaquest.com to request a competitive nutraceutical manufacturing price quote!
Frequently Asked Questions About Formulating and Packaging Shelf Stable Probiotics
What is the best packaging for probiotics?
- There are different package types that are good for probiotics. The use of blister packs helps reduce probiotic exposure to oxygen, light and moisture, which tends to make it more likely to sustain the probiotics’ lifespan through expiration dating. Likewise, dark colored or opaque glass and PET bottles also do a good job of limiting exposure to oxygen, light and moisture.
How do you increase the shelf life of probiotics?
- The use of probiotic strains that are hardy, such as those in the Bacillus genus, tend to have provide a more stable product with a longer shelf-life. Also, the use of blister packs and dark colored or opaque glass and PET bottles limit exposure to oxygen, light and moisture, which can contribute to an increase in stability and shelf-life.
How long are probiotics shelf-stable?
- On average, shelf stable probiotics tend to last up to 24 months.
How do you stabilize probiotics?
- The use of probiotic strains that are hardy, such as those in the Bacillus genus, tend to have provide a more stable product with a longer shelf-life. Also, the use of blister packs and dark colored or opaque glass and PET bottles limit exposure to oxygen, light and moisture, which can contribute to an increase in stability and shelf-life.
What are the techniques used to encapsulate probiotics?
- Encapsulation is a straightforward process. The powdered probiotic is delivered in a hopper into an encapsulation machine. Two-piece capsules are automatically separated so that the bottom piece is available to receive the powder. Once filled, the top piece is fitted over the filled bottom piece, producing a finished capsule.
Are shelf stable probiotics better than refrigerated probiotics?
- Yes. Shelf stable probiotics have better stability and will retain their potency longer. The same is true of refrigerated probiotics.
Terry Coyle, serving as the Chief Innovation Officer at Vitaquest, previously held the position of Vice President for Product Development & Regulatory Affairs. With an MBA from NYU Stern School of Business, Terry boasts 28 years of experience within the company. Leading a team of over 20 scientists, flavorists, and regulatory experts, Terry's remarkable leadership has driven the successful development and launch of an impressive portfolio of more than 12,500 products.
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