A Review on Spoilage and Preservation of Milk and Milk Products

Milk and milk products that provide nutrition have been of fundamental importance since ancient times. These are aids for improving the economic status of cultivators and sellers, as well as the health of consumers. However, microbial contamination may cause these products to spoil, resulting in the potential loss of not only producers and vendors, but also consumers. As a consequence, there is an urgent need to investigate the causes of spoilage in addition to their preservation for long-term use. In this review, we examined the fundamental causes of deterioration of the examined products and highlighted their preservation techniques so that they can be used to meet the food demands of a growing global population. Microbiologist, engineer, and technologist are challenged by the variety of dairy foods to discover the most effective ways to prevent the entry of microorganisms, destroy those that do enter along with their enzymes, and prevent the growth and activities of those that survive processing. Aerobic psychrotrophic Gram-negative bacteria, yeasts, fungi, heterofermentative lactobacilli, and spore-forming bacteria are problematic spoilage microorganisms. The level of recontamination of pasteurized fluid milk products with psychrotrophic bacteria is a significant factor in determining their shelf life. In addition to visible changes in color or texture, the deterioration of dairy foods caused by fungi is characterized by the presence of a wide variety of metabolic by-products, which produce off-odors and flavors and cause visible color or textural changes.