can you use storebought yogurt for the 2 Tbsp, and start making your own from there?
ive been looking at the possibility of making kefir, but i think you need raw milk (illegal here)
Do not use strobought yogurt for making homemade yogurt, it generally cause a sticky bad yogurt, Try to find a homemade yogurt.
BTW, you can make kefir from storebought pastorized milk, you just need a kefir yeast.