Bacteria recovered from whole-carcass rinsates of broiler carcasses washed in a spray cabinet with lauric acid-potassium hydroxide

Authors: Hinton Jr, Arthur; Cason Jr, John; Buhr, Richard - Jeff; Liljebjelke, Karen

Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2009
Publication Date: 12/31/2009
Citation: Hinton Jr, A., Cason Jr, J.A., Buhr, R.J., Liljebjelke, K.A. 2009. Bacteria recovered from whole-carcass rinsates of broiler carcasses washed in a spray cabinet with lauric acid-potassium hydroxide. International Journal of Poultry Science. 8:1022-1027.

Interpretive Summary: Broiler carcasses can be contaminated by bacteria that cause human foodborne diseases and food spoilage. Mixtures of lauric acid-potassium hydroxide (LA-KOH) are soap-like solutions that can be used to cleanse carcasses and kill bacteria on skin of the carcasses. Therefore, experiments were conducted to examine the ability of spray washing carcasses with LA-KOH to reduce carcasses contamination. In the first set of experiments, carcasses were spray washed with different concentrations of LA-KOH. Results indicated that fewer bacteria were recovered from carcasses washed in higher concentrations of LA-KOH than from carcasses washed with water or lower concentrations of LA-KOH. Another set of experiments examined the effect of using different pressures to spray wash carcasses with LA-KOH. Results showed that pressures used to spray wash carcasses did not have a significant effect on reducing bacterial contamination. Finally, experiments were conducted to examine the effect of time on the ability of spray washing to reduce bacterial contamination of carcasses. Results demonstrated that increasing time that carcasses were spray washed significantly reduced bacterial contamination. Findings from these studies provide data that may be useful in designing practical applications for the use of LA-KOH and other soaps to sanitize chicken carcasses during processing.

Technical Abstract: The effect of spray washing carcasses with lauric acid (LA)-potassium hydroxide (KOH) on bacteria recovered from whole-carcass-rinsates (WCR) was examined. Skin of carcasses was inoculated with a cecal paste containing antibiotic resistant strains of Escherichia coli, Salmonella Typhimirum, and Campylobacter coli. The first trial examined the effect of washing carcasses with water, 0.25% LA-0.125% KOH, 0.50% LA-0.25% KOH, 1.00% LA-0.50% KOH, or 2.00% LA-1.00% KOH at 80 psi for 15 sec. Findings indicated that significantly fewer total plate count (TPC) bacteria, E. coli, and Salmonella Typhimirum were recovered from rinsates of carcasses washed with 2.00% LA-1.00% KOH than from carcasses washed with water and that no C. coli were recovered from carcasses washed with 2.00% LA-1.00% KOH. Another trial examined the effect of washing carcasses at 60, 100, or 150 psi of pressure with 2.00% LA-1.00% KOH for 15 sec. Findings indicated that significantly fewer TPC bacteria were recovered from rinsates of carcasses washed with 100 psi than from carcasses washed with 60 or 150 psi. Finally, a trial was conducted to examine the effect of washing carcasses for 0, 5, 15, or 30 sec with 2.00% LA-1.00% KOH at 100 psi. Results indicated that significantly fewer bacteria were recovered from carcasses washed for 5 sec than from unwashed carcasses. Furthermore, significantly fewer TPC bacteria and Salmonella Typhimirum were recovered from carcasses washed for 15 sec than for 5 sec, and no C. coli were recovered from carcasses washed for 15 or 30 sec. Increasing the concentration of LA-KOH or time carcass were washed with LA-KOH also increased pH of WCR samples. Findings from these studies indicate that spray washing broiler carcasses with LA-KOH can affect the number of bacteria recovered from WCR. These studies also provide addition data that may be useful in designing practical applications for the use of microbicidal surfactants in poultry processing operations.