My colleagues father was food scientist at Central Food Technology Research Institute (CFTRI) at Mysuru and he had introduced a culture from Japan that created non-sour curd. But after a month of curd to curd spooned cultures, the native sour bacillus took over and the curd soured. Then a new curd line had to be made with Japanese bacillus from lab.
Non-sour curds, made from cultures similar to the Japanese, are now available in the market . I have not experimented to find out when the curd becomes sour again.
There are scientific reports that say curdling overcomes lactose intolerance, but soured fermented lactose is not absorbed well into the bloodstream in the small intestine and is excreted. But the lactose treated by non souring bacillus is absorbed well.
The nutritional benefit of non-sour curd should be told to the society.