Variable Frequency Stunning and a Comparison of Two Bleed-Out Time Intervals for Maximizing Blood Release in Processed Poultry , ,

Abstract

An electrical stunner, designed such that both frequency and voltage could be varied independently, was tested to determine which combination of voltage and frequency resulted in a stun which maximized bleed-out in broilers. Frequencies and peak voltages tested were, respectively, 30, 60, 120, 240, 480, and 960 Hertz (Hz, cycles per sec), and 50, 60, 70, 80, 90, and 100V. The combination which resulted in best blood release was a peak voltage of lOOv, average voltage of 30v, and a frequency of 480 Hz. The variable frequency stunner was compared to an AC stunner (60 Hz, 50v) for maximizing bleed-out in male broilers. No significant difference was found between the two circuits.Two bleed-out time intervals were tested using three electrical circuits: AC, DC, and variable frequency. Approximately twice as much blood was collected during the additional 30 sec time interval when the DC circuit was employed. It is suggested that processing plants using DC stunners increase bleed-out time from the standard 60 sec to at least 90 sec before the broilers enter a scalder.The electrical cost of operating three electrical circuits for stunning poultry was evaluated. The AC circuit (60 Hz) was most efficient and the DC circuit least efficient in terms of electrical energy used to stun a given broiler. The variable frequency stunner ranked second.

Heart Beat, Blood Pressure, Respiration, and Brain Waves of Broilers as Affected by Electrical Stunning and Bleed-Out

“…Voltage settings of two circuits, AC and high frequency pulsed current, were found to effect greater bleed-out than an optimum voltage setting of a DC circuit during a standard 60 sec bleed-out interval (Kuenzel and Ingling, 1977;Kuenzel et al, 1978). To determine a cause that would explain differences in percent bleed-out of broilers among the three circuits, a polygraph was used to record heart beat, blood pressure, and respiratory rate.…”

“…A voltage setting of 50v and 90v were used for the AC and DC circuits, respectively. The variable frequency circuit utilized was that described by Kuenzel et al (1978). The settings used were voltage, 30v; peak voltage, lOOv (as measured with an oscilloscope); frequency, 480 Hertz (Hz).…”