Hello humans. I am one of the countless trillions. I am of the genus Lactobacillus. My closest million or so friends call me GP, as in gram-positive . I am a simple soul. My great weakness is that I am a lactose addict. I used to live in a classy part of my hosts colon, but my vice has seen me reduced to existing at the very end of the tract, if you see what I mean. I am near the end of my road and at times can see the light at the end of the tunnel. It is not a pretty sight. Before I pass from this world to whatever lies beyond, I would like to leave a legacy for my genus both here and for the unimagined unborn. I believe this to be a noble cause, as of much benefit to you humans as to my colleagues.
My family come from homemade milk kefir from grains. This is what I wish to optimize for us. What suits us best? We of course (as to my cost I all too well know) love lactose. But we favour forming our CFUs on milk fat globule membrane (MFGM). As a simple soul I do not know myself why, although there are sugars and protein there. Do you know why? Does this help us survive the acidic environment that we ourselves exacerbate? I myself clung on for dear life to such a colony on the wild ride through my hosts hydrochloric hinterland. I believe one of your human studies found more of us survive this trip if the fat content of our milk is higher. This is good news. The bad news is that more of us come out the other end in this state, to be detected. Do we get to colonize the colon in greater numbers or are we just there for the ride? What is the role of milk fat? Does this provide us with the environment to flourish, just as lactose is our food source? Why is milk kefir and yoghurt thicker when fat content is higher? Does that mean there is more of us probiotics or is there just more structure to coagulate?
Protein. Our lactic acid causes it to coagulate, manifesting as thicker fermented milk products. Does this indicate there is more of us? That is, more probiotic, more lactic acid, more coagulation? How much curd and whey separation can occur before our population diminishes? Are we a less than a genius genus, committing suicide without our human friends kindly intervention?
We love to chew up protein. We release peptides unique to kefir, a number of which have favourable biological functions. You humans might be benefiting from us in this way.
So what is the best way for us to go forth and multiply? The simple view has been that it is all about the lactose. Food, food and more food. But milk fat and MFGM may well contribute a home for us, or at least in some way assist our survival in our harsh environment. Protein levels may well contribute to our overall benefits and perhaps our numbers. Everything seems important.
Our host has been considering adding various milk solids, such as whole milk powder (WMP), skim milk powder (SMP), or others, to the kefir second ferment (even possibly the first ferment), thus providing a concentrated milk environment. WMP would add all the above ingredients presuming some MFGM remains in it. SMP would cut the otherwise significant calorie load and add more protein and lactose.
Our host being cheap and lazy uses homogenized, 3.5% fat, cow milk. Raw is not available and non-homogenized is expensive and inconvenient to source. Did I mention cheap and lazy?
Further questions surround the adding of prebiotics during second ferment, but that may have to be another topic. This microbe would be interested in any humans experimenting with milk solid addition to kefir ferments.
Stay positive.
GP (hosted for the moment by cave adsum).