Mwaikambo, James Joseph2023-06-192023-06-192001http://www.suaire.sua.ac.tz/handle/123456789/5317ThesisThe study was conducted to investigate the effect of milk preservation by the use of activated Lactoperoxidase system (LPS) on fresh, pasteurised and fermented milk quality. Fieldwork was done at Mwakaleli, Mbeya region, while the laboratory work was conducted at Sokoine University of Agriculture. After collection, milk LPS was activated by addition of sufficient amount of thiocyanate and hydrogen peroxide followed by milk shelf life determination under different storage conditions. The best LPS holding time before pasteurisation was found to be 3 hours followed by 6 hours, whereas the holding time above 6 hours performed poorly. The effect of LPS activation on fermented milk quality was also investigated. No significant (P>0.05) difference in pH between treated and untreated milk was observed on the milk that had a holding time of less than 9 hours, above this period milk recorded significantly (P<0.05) low pH. Likewise was the pH of the yoghurt with more or less similar trend. The analysed natural Thiocyanate content of the test milk was within normal range (4.09±l・l ppm). This indicates the test milk could accommodate recommended external addition of thiocyanate for LPS activation without raising SCN- content above the physiological limits. The LPS carry over effect on milk inocula could not be detected due to the LPS inactivation by pasteurisation (80° C/1 min.). This explains the absence of any noticeable physical, chemical or organoleptic abnormality on milk and milk products final quality. In the field, activated LPS prolonged morning raw milk shelf life for more than 15 hours as compared to less than 12 hours registered by the untreated milk, whereas throughout the experiment under all storage conditions LPS treated pasteurised milk performed significantly (P<0.001) better than the control. In order to solve the problem of raw milk short shelf life in the remote rural tropical environment a cheap and convenient charcoal cooler box was designed, constructed and tested with encouraging results in the storage of raw milk. The cooler performance was 8.94° C and 5.45° C below the environmental maximum and minimum temperatures respectively. When compared to the room temperature storage conditions, the cooler performed significantly (P<0.001) better than the room temperature. Therefore, under any tropical environmental condition accompanied with the absence refrigeration or cold room facilities, the application of both activated LPS and charcoal cooler box for raw milk storage is strongly recommended for the fresh milk shelf life extension to enable the marketing functions to operate.enLactoperoxidase systemMilk productsThesis