Taste changes in yoghurt and ayran can vary with production and distribution conditions. Track measurements and returns for the same lot instead of using a generic temperature table.
Match the lot data. Using the producer's method, record pH or the defined quality measure at production or dispatch and at receipt. Link product readings, timestamps, route and transfer waits to the same lot ID; note stacking and handling movement for ayran.
Investigate repeated differences by route, vehicle or waiting step. For a lot outside its product specification, follow the operating procedure and quality lead's decision.