Milk, microbes, modern science and technology: Holding time low temperature microwave heating pasteurization technique in the production of yoghurt

In this work, the production of yoghurt product was studied from powdered milk through holding time low temperature (HTLT) microwave pasteurization at 63 oC for 30 minutes as an innovative alternative approach to traditional thermal treatments. The study further investigated the influence of storage conditions on the viscosity, pH, and microbial growth of these microwave pasteurized products. It was examined under both ambient and refrigeration conditions with and without preservatives over the storage regimes. The results demonstrated that refrigeration consistently preserved viscosity more effectively than shelf storage, reflecting reduced microbial proliferation, slower enzymatic degradation, and minimized syneresis. In the absence of preservatives, viscosity declined rapidly under shelf storage, underscoring the critical importance of cold-chain logistics for maintaining product quality. However, the inclusion of preservatives significantly enhanced the product stability, inhibiting microbial growth and proteolysis. The viscosity of the products with preservatives under refrigeration was synergistically kept and maintained nearly unchanged, while under ambient was gradually declined and could not prevent its loss over the storage regimes. The observed differences can be mechanistically attributed to the interplay of protein degradation during the longer holding time pasteurization, the suppressing of microbial growth by preservatives, and the dominant effects of refrigeration through syneresis control. Our study concludes with a bibliometric analysis to determine the number of articles, authors, and the most publishing countries.