In last two decades, great efforts have been addressed to increase the study of milk proteomics (especially in human and ruminants) which remains a bioactive biological fluid of great interest. Because of the complexity and multiplicity of milk components, different research techniques have been combined to explore genetic aspects, molecular pathways, microbiota and cellular functions involved in milk production, quality, and safety to gain a multifaceted picture addressing this complexity. Milk is a heterogeneous body fluid occurring in nature to address the nutritional and defensive needs of the mammal’s newborns. It could be considered one of the major feeding resources for humans if considering all the milk products like cheese, fermentation and transformation products. In contrast to human milk, that is a nutrient only in the early life, animal milk and dairy products are nutrients for the entire life of humans.
It has a great biological and nutritional value , milk is the center of the dairy industry where it is mainly transformed into cheese and a diverse array of other milk-by products. Interest in understanding the origin, composition and role of the milk of different animal origin is steadily increasing in the last years, along with the consciousness of the role played by the microbiota in the development and diversification of the myriad of dairy products and functional foods. Besides reducing the pathogenic population, milk treatments exert a profound inhibition of the indigenous non-pathogenic microflora. The large-scale study of proteins (proteomics) can provide information about different protein profiles, characteristics of milk, nutrients, lactation stage, and the relative health status of the animal. More extensively, proteomics is useful for the assessment of safety and quality of both milk and dairy products. Moreover, ruminants’ milk is considered a diagnostic fluid, a biosensor, and metaproteomics investigation of raw milk could represent an index of antibiotic resistance of the environment, giving information about contamination and epidemiology of AMR.