I live in the UK and here you can buy large tubs of plain unsweetened activia yoghurt. I did use a bit in my yoghurt maker.
The tubs of yoghurt are low fat , however (i tend to prefer yoghurt which is not low fat.
What do you think of Onken bio pot yoghurt? It reputedly has acidophilus, bifidus and streptoccocus in it. I have consumed loads.