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Removal of spinal column from cattle and sheep carcasses

Project Code: M03017

30/06/2003

Silsoe Research Institute
Knight, A ;
AVOCET Engineering Services Ltd., Uk
Pole, A; Ham, J;
Freund Maschinenfabrik Gmbh & Co. KG, Germany
Freund, R;
University of Bristol
Fisher, A;
Universitat Rostock, Germany
Koegl, H;
Association pour le Development de L'Institut de la Viande, France
Frencia, J;
Norwegian Meat Co-operative, Norway
Wahlgren, M;
Anglo Beef Processors Ltd., UK
Roberts, J

Background

It is generally accepted that the same agent causes Bovine Spongiform Encephalopathy (BSE) in cattle and variant Creutzfeldt Jakob Disease (vCJD) in humans. In cattle, the agent is predominantly in the central nervous system (CNS), and therefore it is paramount that these tissues do not enter the food chain. BSE has never been found in farmed sheep, but it has been transmitted experimentally. The controls on removal of specified risk material (SRM) are designed to prevent the parts of slaughtered animals most likely to contain the BSE agent from entering the food chain. Furthermore, the efficacy of procedures for removal of the spinal cord and dorsal root ganglia, i.e. some components of the SRM, is of utmost importance since the minimum dose level for humans is unknown.

In most abattoirs, procedures are in place for spinal cord to be removed either manually or with suction equipment after splitting. Some devices are available for suction of cord from intact (non-split) carcasses, but these are not fully effective.

Rationale and objectives

Following a European Commission Decision introduced on 1st October 2000, regulations in all EU states were required for spinal cord removal from all cattle carcasses and sheep carcasses of animals above 12 months of age. Also, the regulations required that in UK and Portugal the vertebral column (including dorsal root ganglia) be removed from all cattle aged over 30 months in UK and 6 months in Portugal. At that time, in UK only a very small number of especially exempt animals aged over 30 months entered the food chain, and for Portugal no reliable system currently existed for removal of spinal column.

In the absence of sensitive ante mortem methods to identify animals infected with a TSE, methods to eliminate the risk of contamination of meat with CNS material are therefore of paramount importance in protecting the workers’ and consumers’ health.

Approach

A novel hand-held oval saw for removal of vertebral column had already been designed, constructed and demonstrated under laboratory conditions. The function of the saw being to completely remove the majority of the vertebral column from inside the eviscerated carcass, ensuring that all cord material and dorsal root ganglia remain encased in vertebral bone.

Various test rigs for both cattle and sheep had previously been constructed and evaluated in research facilities, and a limited number of confidential demonstrations had been conducted to establish a partner consortium for this further work to prove and demonstrate the technology under commercial conditions. To facilitate these proving trials, i.e. the next stage in the development of the technology, required new saws and ancillary equipment for operator and carcass support/restraint.

Outcome / Key Results Obtained

Removal of the vertebral column with the oval saw produces a “non-conventional” carcass in which high value muscles lying alongside the vertebrae, notably the ‘eye’ muscles (longissimus thoracis et lumborum ), are deprived of their skeletal attachments. Furthermore, to prevent excessive damage, the fillets (iliopsaos – the most highly valued beef cut), have to be freed from their medial attachments to the transverse processes of the vertebrae before the oval saw is used. These are important considerations and could potentially affect the commercial acceptance of this technology.

Oval saw equipment systems for both cattle and sheep carcasses were constructed and used to validate the above laboratory results under simulated commercial slaughterhouse conditions. During the early stages of the project, unforeseen difficulties were encountered in achieving successful progression of the saws through the carcasses, which required modifications to the equipment and mode of operation.

An extension of the project completion date allowed the viability of the oval saw to be proven by completion of the functional tests and demonstrations on a simulated food quality slaughter line. The delays due to the earlier problems which required additional work to modify the saw and carcass cutting procedures, prevented completion of the meat quality and economics aspects of the work.

The results of this study have been disseminated to an extended audience across the EU in order to increase awareness and demonstrate the benefits of the oval saw technology. The aim being to inform a wide spectrum of potential users, legislators and consumer organisations. Following the project, further dissemination of the results, possibly leading to implementation and exploitation of the technology, is being undertaken by some of the commercial partners.

Saw functionality:

The operator interface with both the equipment and the carcass had a major influence on successful operation of the saws.
Reversing the direction of cutting through cattle carcasses, from tail-to-neck to neck-to-tail, relieved both compression and vertebral movement within the cutting zone.
Suitable equipment (saws and carcass / operator support systems) are now available for commercial trials with both cattle and sheep carcasses.
Automation, or semi-automation, of the complete spinal column removal process could offer many advantages.

Food safety:

All spinal cord and dorsal root ganglia are removed from the carcass without being exposed, i.e. they remain completely encased in vertebral bone; hence, the hazard of carcass contamination with these materials is eliminated.
This technology offers a safe alternative to existing procedures where carcasses from potential BSE positive animals are processed on food lines.
The technology is unlikely to be adopted by the industry without legislation, but some meat processors are showing an interest in the technique

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