For the manufacture of bone gelatin a down-scaled Pilot model has been developed and tested to reflect as close as possible the industrial processes and to represent the typical manufacturing conditions. Spiking crushed fresh bone with 30 I V infected mouse brain (BSE agent) and 263 K infected hamster brain (scrapie agent) and processing these materials through the down-scaled model to produce gelatin. Using the processed material from the whole process to determine the residual infectivity of gelatin and dicalcium-phosphate by bio-assay. Evaluating separately the inactivation capacity on individual process steps of the finishing unit operations by spiking the industrial starting material and processing this material through these steps and measuring the remaining infectivity. In total 17 samples are prepared and submitted to bio-assay. All samples are additionally tested by immunoblotting.

The objective of the study is to prove reduction or complete removal of TSE infectivity by the gelatine manufacturing process as a whole including all sequential treatments, as well as by specific steps of the process using BSE strains in addition to scrapie strains, choosing the highest achievable infectivity level according to the principles of virus infectivity reduction studies. The level of spiking of the starting material used in the evaluation of the reduction of TSE infectivity by the entire manufacturing process is at least 106 ID50 per gram of fresh crushed bones. This level is sufficient to measure a considerable reduction, while this infectivity is at least 100 times higher than the theoretical highest possible infectivity and approximately 100.000 times higher than the highest infectivity that can be expected in reality, thus:

• Fulfilling demands by several international experts, institutions and regulatory bodies concerning the proof of inactivation procedures with regard to the gelatine process.
• Reassuring the general public and the industries using gelatine and its by-products that gelatine is safe under all circumstances.
• Producing data to carry out an updated risk assessment for gelatine and di-calcium-phosphate.
• Safeguarding the use of slaughtering by-products by adding value and avoiding waste.

To achieve these objectives, the following study design has been chosen after consultation of international experts.

For the manufacture of bone gelatine, a down-scaled pilot model has been developed and tested to reflect as close as possible the industrial processes and to represent the typical manufacturing conditions actually in use. The gelatine manufacturing processes and the down-scaling are described in detail in section IV, 1-5 of the protocol handed over to DG Research on May, 5, 2000.

The down-scaled model and the actual manufacturing processes of the different European gelatine manufacturers have been audited and certified by SGS, a European Quality Certification Institute. The final report certifies that the chemical and physical conditions used in the down-scaled model are in conformity with the minimum conditions described (see section V, 1 of the protocol), and represent the practices in the factories of the involved companies.

Investigated will be the inactivation by the complete manufacturing processes of limed bone gelatine, acid bone gelatine and gelatine manufactured by the heat and pressure process. Further the inactivation by the individual process steps: filtration, ion-exchange and UHT sterilisation will be tested as well as the manufacture of DCP, which is a by-product of gelatine manufacture. Finally the effect of a short treatment with NaOH of the acid treated bone will be tested. The latter is a new process step that could be incorporated in the bone gelatine manufacturing process. The starting material for all these test will be spiked with 301V agent (BSE) or with 263K agent (scrapie) and the obtained products will be bio-assayed in mice and hamsters.

• Proof of reduction or complete removal of TSE infectivity by the bone gelatine manufacturing process as a whole including all sequential treatments and by individual process steps.
• Evaluation of newly developed gelatine production processes.
• Proof that the manufacturing processes used by the industry to produce bone gelatine are safe.
• Confirmation that the technology actually used by the EU bone gelatine producers is appropriate for the production of gelatine free of BSE infectivity.