>They use a combination of food engineering and package engineering to preserve the food without using preservatives.

I don't know specifically about Haldiram's or MTR (I might have tried out MTR Indian food ready-to-eat packs), but some others that I used to buy and eat sometimes (I forget the name, it may have been from an ITC group company - the Indian food and tobacco giant), mention on the package that they use DRDO-licensed technology. DRDO is an Indian defence-oriented R&D organization of the Indian government. The technology was originally developed for soldiers on the field. So likely made in such a way as to last long, and could account for its not tasting that good, and not as good as the same item, but freshly made (obviously).