The effect of activation of lactoperoxide system (LPS) on the quality and shelf life of in-pouch pasteurised milk

Abstract

A study was conilucted to investigate the quality of pasteurised milk made from Lactoperoxidase system (LPS). activated milk. Milk LPS was activated by addition of amounts of thiocyanate (SCN) and hydrogen peroxide, (H₂O₂) as recommended  by the Codex Alimentarius. After LPS activation, the milk was held at ambient temperature (26-27 °C) for 0.3. 6.9 and 12h before  in-plastic pouch pasteurisation was done at 80 °C for 1 min, followed by cooling to 10° C. This milk was then stored under refrigerator (5 °C). Air-conditioned room (14° C) charcoal cooler cabinet (19-20 °C,), and under ambient temperature (26-27 °C. The shelf life and quality of the pasteurized milk was monitored and assessed on the basis Total Plate Count (TPC). Coliform Count (CC) pH and Clot on Boilmg (COB) tests, The LPS activation holding timw before pasteurization that gave the, highest shelf life was 3 h followed by 6 h Post LPS treatment time above 6 h at ambient temperature (26-27 °C) produced milk of more than 40.000 cfu immediately after pasteurisation. resulting into relatively shorter subsequent shelf life under all test storage conditions.  Under all storage conditions throughout the experiment. LPS treated pasteurised milk performed significantly (P<0,001), better than the control. It was therefore concluded that LPS treatment was effective in enhancing the shelf life of pasteurised milk if only the milk was pasteurised within 6 h of treatment before storage.

Keywords: LPS activation, in-pouch milk pasteurization, shelf life

Tanzania J.Agric.Sc; (2003) Vol. 6 No 1(1-12)