Reference: P. VASUDEVAN1, P. Marek, M. K. Mohan Nair, T. Annamalai, M. Darre, M. Khan6, and K. Venkitanarayanan. (1) Animal Science, University of Connecticut, Unit 4040, George White Building, 3636 Horseban Hill Road Extension, Storrs, CT 06269, (2) Pathobiology, University of Connecticut
In vitro inactivation of Salmonella Enteritidis in chicken cecal contents by caprylic acid
Contamination of poultry and poultry products by Salmonella Enteritidis is a major problem worldwide. Chicken cecal carriage of Salmonella can lead to horizontal transmission of the infection, contamination of eggshell with droppings, and carcass contamination during slaughter. Efforts to reduce the carriage of S. Enteritidis in chicken intestinal tract would potentially lead to a decreased excretion of the pathogen in the droppings, which in turn could reduce contamination of poultry meat and eggs. Caprylic acid (CA) is a natural, eight-carbon fatty acid present in breast milk, bovine milk and coconut oil, and is approved as GRAS by the FDA.
Our objective was to determine the antibacterial effect of caprylic acid on S. Enteritidis in chicken cecal contents in vitro.
Cecal contents obtained from sixty, broiler chickens were pooled, mixed with an equal amount of sterile phosphate buffered saline, and autoclaved to eliminate cecal background bacteria. A 5-strain mixture of S. Enteritidis was inoculated at 106 cfu/ml in cecal contents (n=10) containing 0, 50, or 100 mM CA. The samples were incubated at 40°C under anaerobic conditions, and the population of S. Enteritidis was determined at 0 min, 1 min, 8 and 24 h of incubation.
The treatments containing CA significantly reduced (P < 0.05) the population of S. Enteritidis compared to that in the controls. Both concentrations of CA reduced the population of S. Enteritidis by ~ 5.0 log10 cfu/ml within 1 min of incubation, with complete inactivation at 24 h. In non-autoclaved cecal contents, CA had a significantly lesser (P < 0.05) and minimal inhibitory effect on total cecal anaerobic bacteria, compared to that on S. Enteritidis.
Results indicate that caprylic acid could be potentially used as a pre-slaughter dietary supplement for reducing S. Enteritidis carriage in chicken, but its application needs to be validated with in vivo experiments.