The question: What’s the difference between shelf-stable and refrigerated probiotics?

STORE: Independent natural products store in Chicago
Store employee: When you get them on the shelf compared with refrigerated, you have no idea how long they’ve been there or when they were made. The potency goes down over time. Both are still in live form, but some have more enzymes then actual probiotics. When they are in the fridge, it ensures the potency’s OK.

NFM: So the refrigerated version is better?

Store: Always get refrigerated probiotics. Those on the shelf are just not as strong.

NFM: Why do they even make shelf versions, then?

Store: It’s just a convenience thing, and also some of them are like pearls and you can’t stick them in the fridge because they may bind together.

Comment: Amy Fitzpatrick, RD, dietitian and consultant to the dietary supplements industry.

While it would seem that refrigerated products are more likely to retain their potency, some nonrefrigerated probiotic pills, particularly those with specific technology to protect the bacteria from heat, light and oxygen, can also remain viable for an extended period of time.

Manufacturers of high-quality, nonrefrigerated probiotic products place a guarantee of probiotic content at the time of manufacture. They should also include an expiration date. Whether selecting a refrigerated or nonrefrigerated product, retailers should steer customers toward a pill with a high dose of probiotics, and preferably one that also contains prebiotics. This helps ensure viable amounts of bacteria remain at the time of purchase. I look for pills that contain a minimum of 1 billion colony-forming units per dose, but I prefer 10 billion CFUs or more.

The reality with probiotics is that the choice is not just between what’s in the fridge and what’s on the shelf.