GB2318719A

GB2318719A - Maturing raw carcasses

Info

Publication number: GB2318719A
Application number: GB9723000A
Authority: GB
Inventors: Mark Elder; Adele Dunn
Original assignee: Moy Park Ltd
Current assignee: Moy Park Ltd
Priority date: 1996-11-01
Filing date: 1997-11-03
Publication date: 1998-05-06
Anticipated expiration: 2017-11-03
Also published as: WO1998019550A1; GB9622753D0; BR9706909A; GB9723000D0; GB2318719B; CN1218370A

Abstract

A method of rapidly maturing a raw carcass comprises electrical stimulation of pulsed direct current to the carcass including one of the following:- 1) a further chilling step 2) the period of maximum intensity of the direct currents equals the period of minimum intensity (square-wave form) 3) the voltage is 15 to 100 volts, and 4) the frequency of the current is less than 50 Hz. The preferred voltage applied across the carcass is 50 volts at a frequency of 10Hz and an intensity of 45 milliamps with the pulsed current being on for 0.075s and off for 0.025s. The stimulation may be applied for 30 seconds to produce a drop in pH of 0.3 units. The matured carcass may be air chilled. The carcass may be poultry.

Description

TITLE: Improved method of rapidly maturing a raw carcass DESCRIPTION The present invention relates to an improved method of effecting rapid maturation of a raw carcass, especially poultry, such as a chicken or turkey.

The carcass of a slaughtered animal or bird is normally chilled for a substantial period of time to allow natural ageing of the carcass before being processed for human consumption. This requires the installation of maturation and chilling facilities hence increasing the amount of equipment and space utilised in the production of a meat food product. Maturation of the carcasses also means that, at any given time, a substantial amount of stock is tied up in storage. Additionally, the transfer of carcasses to a chilling facility requires the handling thereof which leads to increased microbiological contamination with a corresponding reduction in the shelflife of the food product. It is therefore desirable to be able to effect rapid maturation of a carcass to avoid the necessitity for natural ageing thereof.

It is well-established that the application of electrical energy to a carcass assists in the maturation and tenderisation of the carcass thereby removing the need for an extended, low temperature, ageing period. For example, US-A4358872 (Vanzandt MM) relates to the tenderisation of a meat carcass using a rectal probe to apply electrical stimulation thereto. EP-A-353199 (Eltrn Froll Sri) also discloses a method for the rapid maturation of meat from slaughtered animals by means of electrostimulation. Electrodes are applied to various parts of the slaughtered animal and supply a pulsed current having a peak voltage of less than or equal to 45 volts, an intensity of less than or equal to 1 ampere and a frequency of 15Hz.

SU-1391566 (E. Sibe Techn. Inst.) describes a process to provide increased tenderisation and a reduced ripening time of meat by applying alternating current through the carcass for three minutes. The current is supplied in pulses, with the duration of each pulse of current being 0.3 to 0.4 seconds having an interval of 0.6 to 0.7 seconds therebetween. The voltage is 220V or 380V with a frequency range from 20 to 60Hz.

Whilst all of the afore-mentioned procedures theoretically result in an increased rate of maturation of a carcass, in practice the processes have not been entirely effective for the tenderization of poultry carcasses as the intensity of the electrical current applied thereto has been found to be detrimental to the eating quality of the meat.

It is therefore desirable to provide an improved method of effecting rapid maturation of a raw carcass whereby post-chill maturation of the carcass may be avoided and which does not adversely effect the quality of the meat produced therefrom.

Accordingly, the present invention provides a method of maturing a raw carcass comprising the step of applying electrical stimulation of pulsed direct current to a carcass for a predetermined period of time characterised by one or more of the following: (1) the further step of chilling the carcass after application of the electrical stimulation thereto; (2) the pulsed direct current provides periods of maximum intensity (1) substantially equal to periods of minimum intensity (0); (3) the voltage is 15-100 volts, preferably 30-50 volts, more preferably above 40 volts, especially being 50 volts; and (4) the frequency of the pulsed direct current is less then 50Hz, preferably less than 15Hz, more preferably 8-12Hz, especially tOHz.

Preferably, the current is switched on for a period of 50-80ms and off for a period of 50-20ms, preferably being on for 70-80ms and off for 30-20ms, especially on for 75ms and off for 25ms.

The intensity of the current applied during the maturation process is in the region of 2(in80 milliamps, preferably being 3O60 milliamps and especially being 45 milliamps.

The electrical stimulation may be applied to the carcass immediately after death or alternatively, up to 15 minutes post-mortem. It is preferred that the carcass is subjected to electrical stimulation w seconds after death. The stimulation may be applied to the carcass for a continuous period of 5 to 60 seconds, preferably 20 to 40 seconds, but especially being applied for 30 seconds to produce a drop in pH of approximately 0.3 unites.

The electrical stimulation may be applied to the carcass, by any suitable means, for example, by means of a probe or electrodes.

Chilling of the carcass immediately after electrical stimulation thereof may be achieved in a variety of ways but preferably, is achieved by rapidly air-chilling the carcass for 1-3 hours at 1-20C thereby reducing the temperature of the carcass from body temperature to 5"C.

The application of electrical stimulation to the carcass may be carried out separately from the processing of the carcass whereby a packaged, chilled food product is produced. However, preferably the electrical stimulation is applied to the carcass on a moving line, ie by means of an electrical stimulation station provided at a site along a moving line. The electrically stimulated carcass may then be moved to a chilling station to complete the maturation thereof before being processed and packaged ready for distribution.

It is to be appreciated that the intensity and duration of the electrical stimulation of a carcass to produce the required maturation thereof may vary depending upon a number of factors, such as the age, sex and breed of the bird or animal and on pre-treatment handling.

The present invention will now be further described with reference to the following Example.

Example A live broiler is mounted on a moving line and after death is delivered to an electrical stimulation station for applying electrical stimulation to the carcass, eg. via electrodes, approximately 90 seconds post-mortem.

The electrical energy applied is pulsed DC current and of square-wave form, ie. having periods of maximum intensity (1) equal to the periods of minimum intensity (0). The electrical parameters of the applied stimulation are of particular importance to the method of the present invention. The voltage applied across the carcass is 50 volts at a frequency of 10Hz or lOcps, with an intensity of 45 milliamps per broiler carcass. The pulsed current is on for 75ms and off for 25ms.

The electrical stimulation is applied to the carcass for 30 seconds to result in a drop of 0.3 units in the pH of the bird. The carcass is then moved by the conveyor to a chilling station at which the carcass is rapidly air-chilled for 90 minutes at 1-2"C.

This reduces the temperature of the carcass from body temperature to Soc.

Following chilling of the carcass, the moving line carries the carcass to further processing stations whereby the carcass is processed and packaged ready for distribution.

The electrical stimulation of the carcass, followed by rapid chilling thereof, induces maturation of the carcass thereby removing the need to provide an extended, low temperature maturation period. This reduces the time taken to process a live animal or bird and leads to a reduction in the amount of space taken up by carcasses during the maturation period. The immediate maturation of a carcass also means that a large amount of stock is not tied up in storage. Furthermore, inducing maturation of the carcass whilst on a moving line removes the need to handle the carcass when being transferred to a chilling facility to mature naturally. Hence, the carcass is exposed to less microbiological activity leading to an extended shelf-life of the resultant food product.

Claims

1. A method of maturing a raw carcass comprising the step of applying electrical stimulation of pulsed direct current to a carcass for a predetermined period of time characterised by one or more of the following: (a) the further step of chilling the carcass after application of the electrical stimulation thereto; (b) the pulsed direct current provides period of maximum intensity (1) substantially equal to periods of minimum intensity (0); (c) the voltage is 15 to 100 volts; and (d) the frequency of the pulsed direct current is less than 50Hz.

2. A method as claimed in claim 1, wherein the voltage is 30 to 50 volts.

3. A method as claimed in claim 2, wherein the voltage is above 40 volts.

4. A method as claimed in claim 3, wherein the voltage is 50 volts.

5 A method as claimed in any one of claims 1 to 4, wherein the frequency of pulsed direct current is less than 15Hz.

6. A method as claimed in claim 5, wherein the frequency is 8 to 12 Hz.

7. A method as claimed in claim 6, wherein the frequency is 10 Hz.

8. A method as claimed in any one of the preceding claims, wherein the current is switched on for a period of 0.05s to 0.08s and off for a period of 0.05s to 0.02s.

9. A method as claimed in claim 8, wherein the current is switched on for a period of 0.07s to 0.08s and off for 0.03 to 0.02s.

10. A method as claimed in claim 9, wherein the current is switched on for a period of 0.075s and off for 0.025s.

11. A method as claimed in any one of the preceding claims, wherein the intensity of the current applied is between 20 to 80 milliamps.

12. A method as claimed in claim 11, wherein the intensity of current applied is between 30 to 60 milliamps.

13. A method as claimed in claim 12, wherein the intensity of current applied is 45 milliamps.

14. A method as claimed in any one of the preceding claims, wherein the electrical stimulation is applied to the carcass up to fifteen minutes post-mortem.

15. A method as claimed in claim 14, wherein the electrical stimulation is applied to the carcass 90 seconds after death.

16. A method as claimed in any one of the preceding claims, wherein stimulation is applied to the carcass for a continuous period of 5 to 60 seconds.

17. A method as claimed in claim 16, wherein the stimulation is applied for a continuous period of 20 to 40 seconds.

18. A method as claimed in claim 17, wherein the stimulation is applied for a continuous period of 30 second.

19. A method as claimed in any one of the preceding claims, wherein the stimulation is applied to produce a drop of pH of approximately 0.3 units.

20. A method as claimed in any one of the preceding claims wherein the carcass is rapidly air-chilled for 1 to 3 hours at 1 to 2"C thereby reducing the temperature of the carcass to about 5"C.

21. A method as claimed in any one of the preceding claims, wherein the electrical stimulation of the carcass is applied to the carcass at an electrical stimulation station on a moving line prior to a chilling station.

22. A method of rapidly maturing a raw carcass substantially as hereinbefore described with reference to the accompanying Example.