Conservation of goat milk
Conservation of milk is achievable, among other methods, by means of cooling or freezing, which is one of the methods of conservation of goat milk used in certain establishments in order to get a longer life and greater availability of milk in different seasons (Grille et al. 2013).
Our research group (Faculty of Veterinary, UdelaR) together with PAGRO (IMM) and LATU, conducted a study in order to guarantee the preservation of goat milk by freezing at -18°C for six months, verifying oxidative stability, compositional and microbiological quality. To guarantee the milk preservation the following specific objectives were defined: 1. to evaluate and compare, with respect to raw goat milk, how heat treatment (pasteurization) affects prior to freezing, the various parameters of quality and stability. 2. To evaluate the effect of two methods of thawing on the parameters of quality and stability of goat milk. 3. To evaluate how it affects the freezing times values regarding quality and stability of raw and pasteurized goat milk. The conclusions of this study were that the freezing of goat milk for six months did not affect the quality in terms of the parameters studied, so this method of conservation could be an alternative in rural establishments to maintain a steady volume of goat milk through the year. It is considered important to continue studying the effects of the freezing of the milk used as raw material for cheese making, given that 70% of goat milk produced in the country goes to the production of these products (Grille et al. 2013).
It is noteworthy that this study was developed by producers demand (milk was usually frozen as a preservation method, but this process was not officially approved), so these results were fundamental to draft the “Licensing and countersignature handbook of dairy farms and Artisan dairies” MGAP (2010) (Manual para la Habilitacion y Refrendacion de los Establecimientos Productores de Leche y Queserias Artesanales). In which, it is specified that the goat milk producer can choose cooling or freezing as a method of milk storage. Regardless of the method used, the time between milking and refrigeration or freezing should not exceed two hours. In the case of refrigerated milk, it must meet the same requirements described for bovine milk handling. The freezing of milk, only allowed for goat and sheep milk, should also comply with the following: The milk must be filtered immediately after milking and collected in labelled containers (for traceability) used for first time in freezing. Freezing and / or maintenance of frozen milk should be performed using equipment with storage capacity and cold production compatible with the volume of production and product storage period at the processing establishment. Frozen milk should be kept at lower temperature then -18 °C for a maximum period of 5 months. The equipment used for freezing (freezer) should be used exclusively for milk. It must have a device for temperature control and should be maintained in adequate hygienic conditions (MGAP 2010).