Análises físico-químicas e microbiológicas do leite de vacas leiteiras em diferentes períodos de lactação

Abstract

Milk quality is directly related to physical, chemical and microbiological factors that vary according to management, feeding and, above all, the stage of lactation of the animals. The aim of this study was to evaluate the main physicochemical and microbiological parameters of refrigerated raw milk from Jersey-Dutch cows at three different lactation periods (1, 2 and 3 months postpartum). Samples were analyzed monthly from 15 animals, 5 in each group, for six months, and fat content, protein content, defatted dry extract (DDE), titratable acidity, total bacterial count (TBC) and somatic cell count (SCC) were analyzed. Physico-chemical analyses were carried out using Ekomilk® equipment and a Dornic acidimeter. The microbiological analyses followed classic plating and reading methods, while the Somatic Cell Count (SCC) was assessed using the Milkspec® equipment. The results showed significant variations in milk composition, especially in the early stages, between 30 and 40 days, with the bovine energy recovery process, as well as the last quarter, between 6 and 9 months, with a percentage increase in protein, fat, ESD, an increase in density and a decrease in production volume. The hygienic-sanitary evaluations CBT and CCS reflected good management practices, with results well below the limits imposed by the regulations. The research reinforces the importance of controlling milk quality parameters as a productive and sanitary monitoring tool, which contributes to increasing the added value of the product and compliance with current legislation.