http://trndmonitor.com/dairy-spotlight-latta-russian-kefir-acidophilus-live-probiotic-yogurt/ " GMO & gluten free claim:
Our (Latta USA organic products) proprietary mix of 12 (of 42 known kefir) probiotic strains include: 
Bido-bacterium: 1.(short) 2.longum, Lactobacillus: 3.acidophilus 4.bulgaricus 5.paracasei 6.rhamnosus,
Lactococcus lactis subsp: 7.cremoris 8.lactis 9.lactis biovar diacetylactis, Leuconostoc: 10.mesenteroides 11.pseudomesenteroides, 12.Streptococcus thermophiles."
(Latta also carries non-organic kefir & yogurt - some with 4 probiotic strains, superior to the 2 strain probiotic brands.)
http://www.cornucopia.org/yogurt-scorecard/#sthash.foy0jLpv.dpuf rating score card relating to ORGANIC yogurt and ORGANIC kefir.

Magnesium
@ silverbulletin.utopiasilver.com/naturally-treat-digestive-problems-with-tissue-cell-salts/ Consider Epsom salts.