The effect of sodium bisulfate on Salmonella viability in broiler litter

Controlling Salmonella populations on commercial broiler grow out farms is a crucial step in reducing Salmonella contamination in processing plants. Broiler litter harbors many species of pathogenic bacteria including Salmonella. Sodium bisulfate has been shown to reduce concentration of bacteria in broiler litter. In experiments 1 and 2, sodium bisulfate was applied to broiler litter at rates that are comparable to what is commonly used by the poultry industry: 22.7, 45.4, and 68.0 kg/92.9 m(2). After application, sodium bisulfate was mixed into the litter. In experiments 3 and 4, sodium bisulfate was applied at 45.4 kg/92.9 m(2) to the surface of the litter. For all experiments, a cocktail of 5 Salmonella serovars was applied to the litter. Ammonia, pH, moisture, and water activity measurements were taken; additionally, total aerobic, anaerobic, enteric, and Salmonella concentrations were determined at 0, 24, and 96 h. In experiments 1 and 2, Salmonella concentrations were higher for treated litter than the control at 24 and 96 h (P < 0.001). In experiments 1 and 2, litter pH was lower for treated litter at 24 and 96 h; lowest pH was observed with the 68.0 kg/92.9 m(2), with a pH of 5.95 (P < 0.001). In experiments 3 and 4, litter pH was lowered for treated litter to 2.1 (P < 0.001). Even this lower pH did not reduce Salmonella concentrations compared with the control (P = 0.05). The decreased litter pH appeared to be responsible for increased viability of Salmonella. This research shows that the lowering of litter pH, which decreases litter ammonia production, could actually lead to an increased survivability of certain bacteria, such as Salmonella.