Bacterial flora of skin of processed broilers after consecutive washings in potassium hydroxide and lauric aid

Authors: Hinton Jr, Arthur; Cason Jr, John

Submitted to: Feedinfo News Service
Publication Type: Trade Journal
Publication Acceptance Date: 2/18/2008
Publication Date: 2/19/2008
Citation: Hinton Jr, A., Cason Jr, J.A. 2008. Bacterial flora of skin of processed broilers after consecutive washings in potassium hydroxide and lauric aid. Feedinfo News Service. http://www.fedinfo.com.

Interpretive Summary: This experiment was conducted to determine the number of bacteria on skin of processed broilers after each of five consecutive washes in mixtures of potassium hydroxide and lauric acid. Samples of breast skin was taken from carcasses and washed in distilled water or in 2 concentrations of lauric acid and potassium hydroxide mixtures. Skin was transferred to fresh solutions after each wash, and washing was repeated to provide samples washed for 1 to 5 times in each solution. The number of bacteria on the skin was determined after each washing. Results indicated that washing skin in water for 1 to 5 times generally did not change the number of bacteria on the skin. However, repeated washing in either concentration of the lauric acid-potassium hydroxide mixture generally decreased the number of bacteria on the skin. Washing skin in the most concentrated lauric acid-potassium hydroxide mixture completely eliminated some groups of bacteria on the skin. Findings indicate that washing chicken carcasses in mixtures, such as lauric acid-potassium hydroxide, may decrease contamination of carcasses by harmful bacteria.

Technical Abstract: Bacteria on skin of processed broilers were enumerated after each of five consecutive washes in mixtures of potassium hydroxide and lauric acid. Breast skin was taken from carcasses obtained from a commercial processing facility, and skin was cut into 5 g samples. Portions of skin were washed using a Stomacher laboratory blender to agitate skin in distilled water, 0.50% lauric acid-0.25% potassium hydroxide, or 1.00% lauric acid-0.50% potassium hydroxide. Skin was transferred to fresh solutions, and washing was repeated to provide samples washed for 1 to 5 times in each solution. Washed skin was stomached in Butterfield’s Phosphate Buffer, and Total Plate Count Bacteria, Gram-negative Enteric Bacteria, Lactic Acid Bacteria, and Staphylococci in skin rinsates were enumerated. Results indicated that there was no significant difference in the number of Total Plate Count Bacteria, Gram-negative Enteric Bacteria, or Staphylococci recovered from skin washed 1 to 5 times in water. Repeated washing of skin in 0.50% lauric acid-0.25% or 1.00% lauric acid-0.50% potassium hydroxide generally produced significant reductions in the number of bacteria on the skin, however. Furthermore, no Gram-negative Enteric Bacteria or Lactic Acid Bacteria were recovered from skin washed 3 or more times in 1.00% lauric acid-0.50% potassium hydroxide. Findings indicate that the addition of microbicidal surfactants, such as lauric acid-potassium hydroxide, to processing water may decrease microbial contamination of carcasses by increasing the cleansing activity of water and by killing microorganisms on carcasses and in processing water.