Do I need to refrigerate my Optibac?

The simple answer is no - there is absolutely no need to refrigerate any of the supplements in the Optibac range.

This is because our products are produced in a very specific way to enable what we call our 'fridge-free technology'. Firstly, we select only the most robust strains within a species (find out more about our strains). These already-hardy strains are then put through a process called lyophilisation - a safe, sophisticated stabilisation technique also known as freeze drying. The strains are then tested to ensure that they survive at room temperature, and to ensure that the billions count stated on the packaging is correct.

While all of our friendly bacteria are lyophilised, our friendly yeast Saccharomyces boulardii, undergoes a slightly different stabilisation method known as fluid bed drying (FBD). This advanced method allows less excipients to be used in Saccharomyces boulardii supplements; however, it is only suitable for yeasts, not bacteria.

The stated number of good bacteria in each supplement is valid right up until the expiry date and not just at the time of manufacture.

Scientific explanation

The strength of a probiotic supplement is measured by the number of billion friendly bacteria per gram, capsule or sachet. At Optibac, we guarantee the strength of each of our products at the expiry date of the product. This benefits our customers because in order to deliver on the guarantee, our supplements are far more potent than stated, at the point of manufacture.

Some other probiotics on the market only give their potency guarantee at the point of manufacture, meaning that by the time the product expires there will be fewer viable cultures than stated, due to the inevitable demise of a small percentage of bacteria during its shelf life.

All of our probiotics undergo stability testing which allows us to calculate the additional billions count needed at manufacture, in order to satisfy our billions count guarantee at expiry.

Below is a stability graph for ‘For babies & children’. The orange line marks the number of microorganisms - this naturally drops slightly over time - but remains well above the 'specification', i.e. 3 billion per sachet. As you can see, four different batches have been tested and the average has been taken. The tests were conducted over 24 months, at 25 degrees Celsius/77 degrees Fahrenheit (a higher temperature than the recommended storage in room temperature / a cool, dry place).

Stability graph of Lactobacillus acidophilus Rosell-52Bifidobacterium infantis Rosell-33Bifidobacterium bifidum Rosell-71 under ICH guidelines at 25 degrees / 60% relative humidity

Probiotic strains stability graph

Stability of 'For babies & children' 

Our stability tests are performed at different temperatures to determine the robustness and shelf-life of the strains we use, but in general we are most interested to see how the bacteria survive at room temperatures or slightly higher just to be on the safe side!

Some products in our range have been tested to higher temperatures than others, and still show excellent stability thanks to the robust nature of the high quality strains. For example, ‘For travelling abroad’ has not only been tested at higher temperatures, but also at higher humidity. This is of great importance to a travel product, that could potentially be taken to much warmer and more humid climates.

Non-refrigerated vs. refrigerated

So, are refrigerated friendly bacteria better than shelf-stable ones?

As long as the supplement delivers the number of billions stated on the pack, and the strength is guaranteed at expiry rather than at manufacture, then it need not matter whether a supplement is kept in the fridge or at ambient temperature.

We chose to create shelf-stable products for two main reasons:

  • Firstly, we believe that shelf-stable supplements are more convenient for our customers and can fit more readily in to a busy lifestyle. It is not always practical to keep products in a fridge.
  • Secondly, being shelf-stable means that we do not have to rely on our retailers storing them at the correct temperature, or delivery drivers using chilled vans whilst the product is still in the supply chain. 


So you can be reassured that the entire Optibac range is 'shelf-stable' (ie. can be kept on a shelf, and not in the fridge) for your convenience. This means that you can keep us in your handbag, on your desk at work, or on your bedside table - wherever you won't forget to take it! Do note, however, that it is recommended to store our supplements in a cool, dry place, and away from direct sunlight.

Incidentally, though, if you really, really want to put your Optibac supplements in the fridge, you can!

This FAQ has been created with the help of Dr Kate Stephens PhD | Food and Microbial Sciences; Gut Microbiology (University of Reading), BSc (Hons) Medical Microbiology