Use Of The Lactoperoxidase System To Enhance Keeping Quality Of Pasteurised Camel Milk

Abstract

The activity of the lactoperoxidase-thiocyanate-hydrogen peroxide system (LPS) varies between species. However, its effect on keeping quality of pasteurised camel milk has not been studied. We investigated the ability of a combination of LPS and pasteurisation to lower survival of microorganisms in pasteurised camel milk. LPS was activated in camel milk followed by pasteurisation after 0, 4, and 8 hrs of storage. Shelf life, specific growth rate and final microbial count at 10 and 20°C during storage of the milk were monitored. Shelf life was 15, 32, 17 and 17 days for non-activated control and those pasteurised after 0, 4, and 8 hrs of storage of the LPS activated raw camel milk respectively during storage at 10°C. At 20°C, the shelf life was 6, 13, 9 and 7 days for non-activated control and those pasteurised after 0,4, and 8 hrs of storage of LPS activated raw camel milk, respectively. The number of viable bacteria in untreated samples reached 108 after 45 days compared to 105-107 in treated samples during storage at 10°C. Viable counts were 108 after 15 days in untreated compared to 107-106 in treated samples under storage at 20°C. The mean specific growth rates at 10°C storage temperature were 0.51, 0.2, 0.41 and 0.5 for the non-activated control, activated and pasteurised after 0, 4, and 8 hrs, respectively. At 20°C storage temperature, the mean specific growth rates were 1.46, 0.27, 0.69 and 1 for the inactivated control, activated and pasteurised after 0, 4, and 8 hrs, respectively. The LPS can therefore be used to improve the shelf life of camel milk when activation is done prior to pasteurisation.