Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 7, 1999
Publication Date: N/A
Interpretive Summary: Processing plants immerse poultry carcasses for several minutes in a tank of hot water to make it easier to remove the feathers, but the water is contaminated with bacteria and feces, some of which are carried into the machines that remove the feathers. This experiment tested an alternative procedure of removing feathers at two points during scalding to see whether the microbiology of the defeathered carcasses could be improved by bathing in cleaner water after removing most of the feathers. Experimental results indicated that bacterial contamination already present on the skin of the live birds when they arrive at the processing plant is sufficent to overwhelm any improvements from cleaner scald water.
Technical Abstract: Several non-conventional methods of removing feathers from poultry carcasses, such as simultaneous scalding and picking or steam scalding, have been reported to improve carcass microbiological quality relative to traditional immersion scalding and in-line picking. Many plants have installed multiple-tank counterflow scalders to reduce the numbers of bacteria in the exit scald water. The purpose of this work was to evaluate the microbiological effect of removing feathers from carcasses while they are out of the scald water moving between the tanks of a multiple-tank scalder. Partially defeathered carcasses in such a system would pass through later tanks with relatively cleaner hot water, possibly enhancing any bactericidal or washing effect of the hot scald water, and much smaller quantities of feces and other contamination should enter the last picking machines. In the laboratory processing plant, however, intermittent scalding and picking of carcasses failed to show any reduction in numbers of aerobic bacteria, E. coli, or Campylobacter on carcasses rinsed immediately after the final defeathering step.