Research on Salmonella in broiler litter reused for up to 14 consecutive flocks

The reuse of poultry litter is a common practice in the Brazilian poultry industry for flocks of healthy chickens, due to 2 fundamental aspects: production cost and environmental sustainability. Litter is a potentially important source of infection for Salmonella, which requires characterization by microbiological analysis in different aspects of management and reuse. The objective of this study was to verify the occurrence of Salmonella in broiler litters reused up to 14 times in Brazilian poultry farms. From January 2008 to November 2010, 8,877 samples of litter on disposable shoe covers were analyzed from broiler farms located in southern Brazil. At the laboratory, samples were processed for isolation and identification of Salmonella. Of the total 8,877 samples analyzed, only 2.5, 5.27, and 2.08% were positive for Salmonella in the years 2008, 2009, and 2010, respectively. Linear regression models indicate that there is a significant decrease (P < 0.05) in the count of samples positive for Salmonella with the reuse of litter. After the sixth reuse of the litter, values of samples positive for Salmonella are significantly (P < 0.0001) lower than expected (chi-squared test). Results show that the reuse of treated broiler litter is a safe practice and contrary to expectations, it substantially decreases the bacterial load of Salmonella.