Composition and microbiological quality of refrigerated raw milk in two seasons of the year in Santa Helena, Western of Paraná

Cibele Regina Schneider, Magali Soares dos Santos Pozza, Maximiliane Alavarse Zambom, Deise Dalazen Castagnara, Tatiane Fernandes


The present study aimed to quantify the occurrence of proteolytic psychrotrophic microorganisms and total coliforms in refrigerated raw milk, in addition to assessing the quality through its physical-chemical composition. The samples were collected in 10 dairy farms in the municipality of Santa Helena – Western of Paraná. Two collections were made, one during the spring and the other in the summer. Samples of refrigerated raw milk were carried out directly in the cooling tank, aseptically, packed in sterile bottles and transported under isothermal conditions (± 4ºC) to the laboratory where the physical-chemical composition and microbial populations were determined. The levels of fat had great amplitude between the seasons, being higher in the summer, while there was no variation for the contents of protein, lactose, minerals and solids non-fat. The total coliform count did not differ between seasons. The values obtained for counts of proteolytic psychrotrophic were higher in the summer. A significant positive correlation was found between the total coliform counts and the counts of proteolytic psychrotrophic and the levels of protein, solids non-fat, and minerals. Also, the counts of proteolytic psychrotrophic showed a positive correlation with the cryoscopic index. The milk components met the requirements of NI76. The quality of refrigerated raw milk in the western region of Paraná was not satisfactory about total coliforms, due to its high incidence, indicating the need for good practices in milking management.


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