My six-year-old daughter takes a probiotic supplement called Primal Defense  (purchased at health-food stores) in order to improve her digestion. It was recommended by a naturopathic doctor after she tested positive for many food allergies -- wheat, dairy, beef, chicken, soy, eggs. (Most of those are 'slow acting' allergies, i.e. no reaction other than general digestive issues, so it's not as bad as it sounds, although eggs is a severe aniphylactic allergy.)
I was skeptical about the supplement at first, a green powder that costs $65 for an 80g jar. But within a week we noticed huge changes, the main one being her saying "I'm hungry!" for the first time! She began naturally drinking more water and eating better meals. That was 1.5 years ago, my skepticism's gone and she still takes it every day (the scoop is tiny though, it lasts for 4-6 months). I bet if we paid for another allergy test she would score much better on most things.
Anyway, the other day I happened to be scooping it into her milk when I noticed the list of 12 species of "healthy soil organisms" that it contains:
Lactobacillus plantarum Bacillus subtilis
Lactobacillus brevis Bifidobacterium breve
Bifidobacterium bifidum Lactobacillus paracasei
Lactobacillus salivarius Lactobacillus casei
Bifidobacterium lactis Bifidobacterium longum
Lactobacillus acidophilus Lactobacillus rhamnosus
Interesting, I thought, lactobacillus are supposed to be what's in my sourdough culture. I googled them and found that several of these friendly microbes have indeed been found in sourdough before. See here for example: http://www.nyx.net/~dgreenw/whatisthemicrobiologyofsan.html 
I'd also been reading some old forum posts on thefreshloaf.com, arguments about whether a homemade sourdough culture is as good as one that you order . Although I took it with a grain of salt*, one of the points seemed to be that while a homemade culture may have captured wild yeast and can thus leaven bread, it's the variety of lactobacillus species that will contribute to the flavour. So a homemade culture is unlikely to have as good flavour as one that's been passed down for decades.
*I made sure to keep the salt out of my starter - ba-doom-tsss! :-)
Well, you can see where this is going. I wasn't sure if I bought the above argument, but I thought, I'll experiment with creating a new starter by adding Green Stuff (aka Primal Defense) to some of my existing starter. In a separate container of course! Maybe it'll improve the flavour and possibly make the starter healthier too! (yes, I know the bacteria will all be killed in a properly baked loaf of bread, but I'm not so sure about the soft centre of my pancakes...)
Day 1: Took a small amount (1 tsp) of my starter, mixed with about 15g water. [Sorry, I don't remember the exact amounts -- the whole thing seemed pretty silly at the time] Then I stirred in 15g AP flour and one scoop of the Green Stuff, this is less than 1g but supposedly contains three billion active probiotic cells. Here is what it looked like:
Day 2: After 24 hours or so, there was very little activity. Several small bubbles but no sign of any increase in volume at all. I didn't take a picture (but it looked almost the same as above anyway). At least it did smell somewhat like hungry starter, combined with the still strong smell of Primal Defense (which smells like seaweed).
I threw out all but 12g or so, and added 40g water, 30g AP flour, and 10g rye. The rye was to help the yeast along, as my regular starter seems to really like rye.
Day 2 (Evening): Good news! About six hours later I checked the starter and there was definite activity. In fact, it had more than doubled in volume in that time, which is more than my regular starter usually does in 6 hours. I took some pictures:
You can see above the faint red line (a kid's marker) which is the level when I refreshed it.
At this point I was happy there was some activity, although a little nervous at how much. The smell was still good, a similar but more complex aroma than my usual starter, with still a hint of the Primal Defense seaweed.
Day 3: I refreshed the starter in the morning. 10g starter, 40g AP flour, 5g rye, 45g water. It had definitely reached the top of the container. I didn't take any pictures at this point as I didn't want to be late for work.
Day 3 (evening): The starter ended up tripling or quadrupling in volume to reach the top of the container in about 10 hours. Wow! Here's the proof:
(faint red line, above, was the refresh mark from the morning)
The faint trace of seaweed smell was gone, the starter again smelled like my usual starter but slightly more complex. I fed it again in a few hours.
Day 4 : By the morning it had reached the top of the container again! Very active for sure. My house temp is pretty stable, 72-74F during the day and 69-70F overnight. So I don't think temperature accounts for the increased activity. I should note that when refreshing the starter I was adding the water first, putting the lid on and shaking it up like crazy, as suggested by Ed Wood in Classic Sourdoughs. This is something that I wasn't doing previously, so it's possible my usual starter might show similar vigor if given the same treatment.
Unfortunately I was running late and couldn't feed it, so it had to wait until after work. I felt bad for neglecting it, hopefully it will spring back alright.
I think this pretty much ends the diary... the starter now seems pretty much like a regular active starter, although exhibiting some different characteristics to my usual starter.
I think the real test now will be to bake with it and see if I can tell a difference in leavening ability, texture, or taste. I will report back then!
- Mike Lucas