How Does Temperature Affect Probiotics?

By Larry Newman
Chief Operating Officer
Kirkman Group, Inc. 

ConsumerLab, an independent laboratory that monitors the quality of nutritional supplements for consumers, was recently asked a question about why some probiotic labels say to refrigerate while others containing the same strains and potencies say no refrigeration is needed.  ConsumerLab correctly answered that question, in its December 2017 newsletter, by stating that all probiotics are sensitive to heat and moisture and refrigeration is one way consumers can make sure their purchased probiotics retain potency and remain efficacious regardless of what the label instructions say.  It is true that there are some probiotic strains that are stable in room temperatures, however none are stable in extreme temperatures and high humidity.  Let’s examine the nature of probiotic products and how they work for a better understanding of why refrigeration is the best way to assure full potency for the consumer.

What Exactly Are Probiotics?

Probiotics are scientifically defined as living microorganisms that, when ingested in sufficient numbers, can impart a health benefit on the host.  Probiotic microorganisms are friendly, desirable and beneficial bacteria that help maintain the correct balance of good and bad (disease producing) bacteria in the gastrointestinal tract by crowding out the undesirable bacteria.  Approximately 100 trillion bacteria live in the human body, and generally healthy individuals have a ratio of about 85 percent good bacteria to 15 percent bad bacteria.  Good bacteria in the gut help to improve gastrointestinal health, improve immune response and aid in digestion.  Good bacteria also break down toxic by-products of bad bacteria, which can negatively affect health.  

Probiotics Must Be Alive to Be Effective

It is important to remember that all probiotics are not the same.   Probiotics must be alive to be effective.  Exposure to heat, moisture, and oxygen are detrimental to the cultures and, depending on the degree of exposure to those elements, the number of live organisms in the culture can be reduced or in extreme cases killed completely. Using a dead probiotic equates to using no probiotic. When Kirkman® makes a claim on a probiotic label for a given number of colony forming units in a product, we back it up with the right operating procedures to guarantee that label claim and perform ongoing stability studies to substantiate our “best used by date” when recommended storage conditions are met. 

Several years ago, ConsumerLab did a survey on probiotic products in the marketplace and found that many products being sold had little or no live bacteria.  In fact, that laboratory found that many of the products tested had less than 1% of the claimed number of live bacteria.  More recent surveys show improved results in marketed probiotics, which ConsumerLab attributes to retailers having more adequate refrigeration in their stores.

How Does Kirkman® Ensure the Quality of Its Probiotics?

Kirkman® has some of the most rigid procedures in the industry for manufacturing, packaging, storing and shipping probiotics.  These include:

  • all live strain cultures are shipped to Kirkman® on dry ice;
  • live cultures are stored in freezers prior to use;
  • all manufacturing is done in dehumidified, cool environments;
  • encapsulating rooms are dehumidified and air conditioned;
  • capsules manufactured are refrigerated during laboratory testing prior to packaging;
  • packaging takes place in a dehumidified, cooled environment;
  • packaged bottles receive an oxygen absorber prior to the capping of the bottle to rid the container of air and moisture, which cause degradation;
  • packaged inventory is stored in refrigerators prior to being shipped;
  • products are shipped on ice with special shipping schedules in the summer;
  • customers are advised to refrigerate products upon receipt;
  • significant overages are used in formulation to ensure full potency and compensate for any potency loss during handling;
  • stability testing assures potency through the “best used by date” on the label if recommended storage conditions are met;
  • a special protective polymer coats the live cultures Kirkman® uses so that their passage through the acidic environment of the stomach is assured; and
  • all strains of probiotics used by Kirkman® have been proven to be safe and effective by the manufacturer of the strains and certified to be properly identified.

Kirkman® advises customers to store probiotics in the refrigerator upon receipt. Some companies say their probiotics are specially formulated and don’t require refrigeration in shipping or storage for proper stability.  Kirkman® challenges that statement as did ConsumerLab in their December 2017 newsletter.  

The fact is that no matter how a probiotic is formulated heat and humidity negatively affect its potency.  On a 100-degree-day in cities such as Tampa, Miami, Phoenix or Dallas, probiotics that sit in a delivery truck or mailbox for any length of time will be killed and no longer be effective regardless of what the brand or what manufacturing process is involved. 

 How Does Short or Accidental Exposure to Heat Affect Probiotics?

Kirkman® often receives calls from panicked customers who have accidently left their probiotic out of the refrigerator for a period of time.  If the temperature involved is not extreme, the product is likely still potent and efficacious. 

Here are a few guidelines to follow that can help you determine if you have cause for concern:

  • When checking your probiotic, consider the temperature of the contents inside the bottle rather than the outside or room temperature.
  • Refrigerated probiotics left out in room temperatures (under 74 degrees) for 24-48 hours and then re-refrigerated should retain full potency.
  • Refrigerated probiotics left out in temperatures 75-80 degrees for 24-48 hours will likely degrade about 5-10%, but will still be effective because of the overage used in Kirkman’s formulations.  Longer periods of exposure increase the degradation. 
  • Refrigerated probiotics left out in temperatures 81-85 degrees longer than 24-48 hours will likely degrade by about 25 percent but will still be effective because of the overages that Kirkman® uses.
  • Refrigerated probiotics left out in 90 degree plus temperatures longer than 24-48 hours likely have experienced significant kill and may no longer be effective.  
  • Probiotics left out in extreme heat (75-85 degrees or more) for very short periods such as an hour or two, will likely be okay because the contents inside the bottle have not heated up in that short time, plus an overage was present.  
  • Probiotics shipped on ice by two-day shipping methods may arrive with the ice packs melted.  If the bottle feels cool or about room temperature, the product is still fine.  If the bottle feels hot to the touch, degradation to some degree has occurred.   If the bottle has been very hot longer than about two or three hours, substantial kill has likely occurred. 

The bottom line is take care of your probiotic after receipt or purchase to maintain its viability. Probiotics are much more fragile and prone to degradation than most other supplements. If in doubt, refrigerate.

All Kirkman’s probiotic products are hypoallergenic and free of common allergens,  including casein, gluten, soy, peanuts, tree nuts, egg, milk, fish, shellfish and wheat.  In addition, no flavorings, colorings, gelatin or corn are present.  The capsule shells are made of plant cellulose to eliminate animal gelatin, which is a concern to some individuals.

Larry Newman

About Larry Newman

Larry Newman is Chief Operating Officer, Technical and Regulatory Affairs at Kirkman Group, Inc. He is one of the country's leading experts in the manufacturing of dietary supplements.
This entry was posted in All, FAQs, Gastrointestinal Health, Probiotics. Bookmark the permalink.

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