Characterization of milk and quality classification by Cluster analysis in dual purpose systems

Abstract

Due to lack information about the milk quality and heterogeneity in dual purpose systems in the Mexican tropics, training is not directed to groups where is required. Therefore, the aim of this study was to characterize the milk of these systems compared to the reference standards and to establish the relationship with management practices. Addition to proposing a methodology to identify groups and production units that require intervention actions. Physicochemical and microbiological composition of 192 raw milk samples from different production units in seven locations were evaluated. The effect of management practices on the characteristics of milk by analysis of variance was determined. A cluster analysis was applied for grouping the samples based on the fat content, nonfat solids, titratable acidity and cryoscopy. A 65 % of the samples showed values out of specification (solid, density and cryoscopy, suggesting an adulterated milk with water). The use of oxytocin, milking type, breed, production system and supplementation affected (P<0.05) the yield and characteristics of the milk. Through Cluster analysis five quality groups were identified. Groups of excellent and good quality showed values within or close to the reference standards in all parameters evaluated. The groups of poor, bad and very bad quality (47 %) had high values of cryoscopy and low solids content. Through the proposed methodology is expected to facilitate the directed intervention from government and private agencies to solve the problems identified, avoiding the waste of supports.