if there are some weaknesses, please suggest some solution to overcome these weaknesses.. thank you.
Possible difficulty of cleaning is the first thing that comes to me. So keeping clanging in mind while designing would be wise. My experienced with heat exchangers is with waste water, where cleanliness per se was not so important, but we did have keep the thing clean enough to maintain efficiency and avoid clogging. Even that was some work, I imagine keeping up to food standards would be at least an order of magnitude more difficult. Also I suspect yogurt is shear sensitive, so you will probably want to avoid abrupt changes in direction and narrow passages.
