Natural Factors Travel Biotic - 10 Billion Active Cells - Morianga BB536 is a proprietary room-temperature stable strain of Bifidobacterium longum. This is one of the most researched and effective probiotic strain. A travel friendly probiotic that does not require refrigeration, Travel Biotic is ideal for supporting digestive health while travelling, taking antibiotics, or for replenishing healthy gut flora. Specially formulated to resist breakdown in the stomach's acidic conditions, it dissolves in the non-acidic conditions of the intestine to yield maximum benefit.