Effect of Deep-Stacking at Different Levels of Moisture Conternt and at Different depths on Safety of Broiler Litter

The present study was conducted to investigate the effects of deep-stacking process on temperature and pathogenic bacterial survival of Broiler Litter (BL). Broiler litter، deep-stacked to 3 depths (30، 60 or 120 cm) and at 3 moisture levels (15، 25 or 35%) was made use of in a split plot design، experiment last for 21 days. Daily temperature of the deep-stacked BL at different depths and at different ambient temperatures were recorded. At the finite temperature of the deep-stacked BLs، representative samples were taken from different depths for later bacterial analysis. The effect of depth on temperature of deep-stacked BL was significant among the day’s 2 to 13 (P<0. 05). Higher moisture level increased the temperature of deep-stacked BL on days 1-4 and 9-21 (P<0. 05). The interaction effect of depth × moisture on temperature of deep stacked BL was significant (P<0. 05). Total count of bacteria in the deep-stacked BL treatments decreased as compared with the control treatment (P<0. 05) with the exception of the depth of 30 cm of 15% moisture and as well the depth of 120 cm of 25% moisture. Mean populations of Coliform bacteria in the depth of 30 cm with 25% moisture and in the depth 30 and 60 cm of 35% moisture amounted to zero. There were no Escherichia coli populations found in at the different depths of deep-stacked BL of 35% moisture. Mean populations of Salmonella in depths of 30 and 60 cm with 25 and 35% moisture contents and at the depth of 120 cm with 35% moisture content were recorded as zero. Overall، deep-stacking BL with 35% of moisture for 9 days (to reach the final destined temperature) decreased the total count of bacteria and other Coliforms and as well eliminated the pathogenic bacteria (Escherichia coli and Salmonella).