The Influence of Knife Sharpness on Poultry Processing Operator Exertions and the Effectiveness of Re-Sharpening

Abstract

A procedure is described to establish knife-sharpening schedules for poultry and meat-processing operations based on increased force due to knife dullness from repetitive use. Knife sharpness was quantified using a novel apparatus described in this paper that measures the area cut by a knife into a carrageenan gel target for a controlled load at the handle. Two meat-cleaning jobs in a poultry-processing plant were analyzed. One job required significantly more force and a greater number of cuts than the other. Eight experienced operators participated in the study. Four fresh ground and honed knives were randomly used by each operator for 4, 45, 75 or 125 cutting cycles. An empirical model of knife dulling and re-sharpening was developed, and the corresponding increase in force was predicted for various cutting and re-sharpening frequencies. The model showed that it took 57 and 125 cutting cycles for the high and low force jobs respectively to achieve a similar reduction in target surface area of 30%. This reduction in target surface area corresponds to a similar percent increase in force needed for the same cut in carrageenan gel as compared to a fresh knife.