Secret Shopper: Do all probiotic supplements need refrigeration?

It used to be that the vast majority of probiotics required refrigeration. Natural products retailers would stock them in fridges in the aisles, and consumers were advised to store these supplements in their home refrigerators. Keeping the capsules cool was often the only way to ensure that the beneficial bacteria inside stayed alive, which is necessary for probiotics to work within the human body. 

For some probiotic supplements, this is still the case. But today, as most retailers know, a growing array of probiotics in diverse delivery formats don’t need refrigeration. These products can sit in the backrooms at room temperature and sit on regular shelves, alongside most other supplements.

When shoppers notice the increasing probiotic options not sold from a fridge, some may find this confusing. After all, it seemingly contradicts the long-held rule of thumb: Keep probiotics cool. Inquisitive shoppers may ask store staff to explain the apparent shift in storage practices, and retailers should have the knowledge to help them understand.

To see how one store handled this question, we put our Secret Shopper to work. Then we asked a probiotics expert with the International Scientific Association for Probiotics and Prebiotics (ISAPP) to assess whether the store’s staffer knew their stuff.

Related:Boost the vitamins and minerals aisle for dietary supplement success

Natural Foods Merchandiser: Do all probiotic supplements need refrigeration?

Retailer: Nope! There are plenty of probiotics that you can just stick in your medicine cabinet instead of the fridge, including any of the ones you see on our shelves. We do have some that need to stay cool, so we keep those in that little fridge over there.

Natural Foods Merchandiser: What’s the difference between them? Why do some need refrigeration and others don’t?

Retailer: That’s a great question. I think it’s mostly due to how probiotics are manufactured. Nowadays, they can do something to them that keeps them alive for a lot longer. It depends on the strain too. Some strains are just stronger survivors, I guess you could say, while others are more finicky.

Natural Foods Merchandiser: Are refrigerated probiotics more effective than shelf-stable probiotics—or vice versa?

Retailer: No, not necessarily. As long as you store them however the instructions on the bottle say, they should work.

How did this retailer do?

Our expert educator: Gabriel Vinderola, Ph.D., ISAPP board member, associate professor of microbiology at National University of Litoral in Argentina and principal researcher at CONICET, the National Scientific and Technical Research Council of Argentina

The retailer did a great job, indeed. I wish all retailers had that level of knowledge!

Let’s go a little more in depth. The need (or not) for refrigeration depends mainly on the technological process applied to produce and preserve the strain. Broadly, probiotics are grown as live cultures, where the cells in their active form need warmth, moisture and nutrition to stay alive and multiply. In order to create the product formats we know today, such as capsules and powders lasting many months or years, probiotic cells are put into a dormant state by processes such as freeze-drying.

Each manufacturer has different techniques for producing and stabilizing probiotics, many of which are kept as trade secrets. These and other processing and production factors, as well as the genetic qualities of the strain (for example, its intrinsic resistance), influence the storage conditions required for the desired shelf life.

Overall, the rule is to follow the manufacturer’s instructions for appropriate storage conditions for each particular product. While some probiotic products are in a dry powdered form, you can also find probiotics in liquid product formats, and both are meant to be preserved at room temperature during storage.

Historically, most freeze-dried probiotics were sold refrigerated, but changes in technological processes and product formats have enabled many preparations to be sold at room temperature today. One particular type of probiotics—spore-forming probiotics such as Bacillus species—typically do not require refrigeration because they take the form of spores, a very resilient type of “dormant” cell.

Interestingly, one common technological tool to improve viability during storage is to expose the microbe to some acidity, some higher temperatures after growth and some osmotic stress. This stress exposure makes the microbe produce natural protective proteins that confer enhanced survival capacity during storage.

In relation to efficacy, it cannot be anticipated that one form is more effective than another. What counts is the existence of a well-conducted human clinical trial on the specific probiotic strain to support the claimed health benefits.