Abstract:
The study was conducted to investigate the keeping quality
of raw cow`s milk preserved by activation of the
lactoperoxidase system in Tsaeda-Christian, found in the
sub zone Berik, Zoba Maekel. Three levels of sodium
thiocyanate 10, 14, 18 and sodium percarbonate 20, 30 and
40 mg/L were respectively used to activate the raw milk
samples and stored at incubation temperature (300C).
Chemical composition, pH, total bacterial counts (TBC)
were evaluated. Moreover, alcohol test and clot- on- boiling
tests were performed. Activation of LPs in raw milk leads
to improve the keeping quality. There were significant
variations (P<0.001) in pH and TBC among the treatments
throughout the storage period. The milk in all treatments
remained fresh during the first 12 hours but the control
became spoiled by the 14th hour. LPs treatment extended
milk shelf life by 6, 8 and 8 hours, for 10+20mg/L (LP1),
18+30mg/L (LP2) and 20+40mg/L (LP3) sodium
thiocyanate and sodium percarbonate, respectively as
compared to control under storage temperature conditions
(30°C). From all parameters measured, LP2 and LP3 were
the last treatments to spoil. Clot-on-boiling test detected
milk deterioration 2 hours later than the other quality tests.
The results revealed that no difference in milk composition
(fat, protein, lactose, SNF, TS, and density) among the
control and treatment samples. Therefore, this extension in
the shelf-life of milk provided sufficient time for milk to be
stored, transported and sold in its fresh state in the local
markets without refrigeration and may encourage dairy
farming in collection of more milk of high quality.
