Many brands don't specify which strain it is. And some of the ones I have found contain gluten.
L. rhamnosus is usually associated with milk in dairy. I'm not sure if that means it's already in most milk or if it's a probiotic that's added to milk as an extra that you would buy at a health food store. I have written about this before, but I acquired EC after I stopped drinking milk. If I drink a lot of milk now, I often get a stomach ache. Maybe that means I'm lactose intolerant, but there are digestive enzymes to help with that.