Behavior of the Physiochemical Parameters of Raw Milk Stored in Temporary Horizontal Storage Tanks

Milk is a product with a high nutritional value, and it may appear in daily meals in its natural form or processed and transformed into various milk products. To be processed in industry, milk must have the proper quality conditions for its consumption, and the levels of its constituents must fall within the standards indicated by Normative Instruction no. 62 (2011). Due to its composition, its constituents tend to separate when at rest. In this context, the objective of this work was to evaluate the behavior of the physiochemical parameters of chilled raw milk stored in temporary horizontal storage tanks. With the milk at rest in the tank, collections were made of the milk at the times of 0, 60, 120, 180, 210, 240, 270 and 300 minutes. These collections were performed at two points of the tank: at the top collection point (Ps) and the bottom collection point (Pi) of the tank. After the collection of the samples, the following parameters were determined: fat (G), non-fatty solids (SNF), density (D), cryoscopic index (95), protein (P), lactose (L) and solids (SI). After completion of the tests, it was possible to verify that the solid constituents of the milk showed different behaviors, since the fat separated completely at 210 minutes promoting a stabilization in the separation of the fat. This same behavior was found for Density and the Cryoscopic Index. The other solid constituents of the milk didn't separate, maintaining themselves stable in both the bottom and top of the tank. As such, the conclusion can be drawn that fat is the only physiochemical compound that separates from milk at rest, thus affecting its Density and Cryoscopic Index.