Exploring the relationships between coagulation, composition, and hygienic quality of bulk tank milk from Manchega sheep

Abstract

Milk from Manchega sheep is the raw material for the elaboration of Protected Designation of Origin (PDO) Queso Manchego, a hard-pressed cheese with one of the most established quality marks on the market worldwide. For this reason, milk quality control in this breed is one of the main targets of the dairy sheep sector. However, pricing systems still continue to apply criteria based only on milk composition and the current legislation on food hygiene. The aim of this study is to explore bulk tank sheep milk quality, estimating milk coagulation properties and their relationship with composition, somatic cell counts, and differential microbiological quality. For this purpose, 308 bulk tank milk samples were collected with seasonal periodicity, and analyses were performed for the aforementioned traits. The obtained results highlight the variability in composition, microbiology, and coagulation properties in different samples, which prevents clear relationships between milk quality parameters. However, there was evidence of a group of milk samples whose coagulation would be desirable for cheesemaking, based on values for fat, protein and total solids. Outcomes also stand out casein content as an important parameter to affect curd yield, proving the interest of using casein as trait for genetic improvement in dairy sheep breeds.