Friendly bacteria themselves should be fine undergoing the process of freezing, however for the OptiBac range we would not recommend freezing the capsules as there is a possibility that the capsules themselves could deteriorate during the freezing & defrosting period.
So from our range, it's fine to freeze the products which come in powdered sachets (For babies & children, One week flat, and Bifidobacteria & fibre), but we wouldn't recommend freezing the other products in the range.
If you are wondering about freezing live cultures other than those in our range, the answer will probably depend on the quality of the live culture strain in question. Freezing yogurt drinks should not damage the live cultures - this process causes the bacteria to enter a dormant state, which is reversible when consumed. If you are in any doubt we would always recommend consulting your supplier directly.