For a probiotic to have reliable, therapeutic results, it must fulfill ALL of the six criteria listed to below to ensure safety, potency and bioavailability:

1. Manufactured in a cGMP Facility and stored in dark, glass bottles only

Make sure the probiotic is manufactured in a facility that carries the cGMP (current Good Manufacturing Practices) certification, otherwise you risk consuming a contaminated product. Contaminants could consist of lead, mercury (and other poisonous heavy metals), and undesirable bacteria. A 1990 independent laboratory study found that nine out of ten brands of popular Lactobacillus acidophilus probiotics actually contained no acidophilus at all. All nine contained contaminants and other species of lactobacilli instead. Probiotics are also sensitive to (and damaged by) light and moisture. Only a glass bottle will keep out all moisture – all plastic is permeable to varying degrees of moisture. In addition, the glass must be dark (or amber colored) to keep out light, which also damages bacteria.

2. Different species must not be touching each other

Different species of bacteria placed together will compete for space and try to dominate each other, resulting in competitive exclusion by the dominant species. In vitro studies have shown that when you place different species together, the dominant (strongest) species will usually produce bacteriocins that kill closely related species.(1)

Therefore, each species (eg. acidophilus, bifidum, bulgaricus) must be kept in its own bottle or in separate capsules. Refrigeration does not prevent this from happening either, since certain bacteriocins have proved stable at temperatures as low as -20 degrees Celcius. I know most probiotic manufacturers sell regular capsules or powders with anywhere from 3 to 14 different species packaged together in one jar, or one capsule. Again, I’m absolutely mystified as to why they do this. However, check the bottle and you’ll see that none of these manufacturers guarantees the number of live, viable bacteria in their product through to the date of expiration. Nor do they guarantee how many of each species and strain remains alive and viable for effective colonization in the gut at time of consumption. See Quality Concerns below.

3. Probiotics must be kept refrigerated at all times

The bacteria need to be stored in a fridge at the store and they must also be shipped in refrigerated trucks to the store. Heat quickly kills bacteria and even at room temperature they will become active and soon live out their life cycle – think of what happens if you leave yoghurt on the counter. The best way to preserve bacterial potency is by keeping it cold at all times, until you’re ready to ingest it. Freeze drying is the best method of preserving the bacteria and for this to be maintained, they must be kept very cold at all times until you’re ready to ingest them. Of course, keep your probiotics refrigerated at home too.

4. Strain and number of bacteria per serving must be listed on the bottle

Only certain strains of bacteria are potent and effective (eg. L. bulgaricus DDS-14 is excellent, L. bulgaricus DDS-13 is useless – remembe