Skip to main content

Dairy products in Mediterranean sheep populations: quantification of scrapie risk

Final Report Summary - RISKSCRA (Dairy products in Mediterranean sheep populations: quantification of scrapie risk)

Considering the large amounts of sheep milk processed in the Mediterranean area, the dairy industry represents a strategic area within the agricultural and food economy. Milk sheep production is 1.3 % of the total milk production. The Mediterranean basin, with 60 % of total production, is the most important area. The dairy sheep industry is usually based on local breeds which are very well fit to their production areas, systems and environments.

One of the main problems across EU countries is to date represented by transmissible spongiform encephalopathies (TSEs). Scrapie is one of a number of TSEs and is a fatal brain disease of sheep and goats. Scrapie develops when the normal form of the prion protein (PrP) in a sheep's brain converts to an abnormal form. After a period of several months it causes nervous system dysfunction and, eventually, the death of the animal.

Experimental studies have shown that bovine spongiform encephalopathy infection (BSE) is transmissible to sheep following oral and parental challenge. BSE affected sheep have a tissue distribution of infectivity and pathological changes similar to those of scrapie affected sheep. Now, abnormal prion proteins have been founded in the mammary glands of sheep affected by scrapie and mastitis. The suspect that TSE in sheep could be BSE rather than traditional scrapie lead European institutions to promote breeding plans for TSE resistance in the European countries. The PrP gene, which produces this PrP protein, also determines a sheep's resistance or susceptibility to TSE.

The sheep PrP gene has two copies (alleles), one derived from each parent. Each codon on the gene translates into one of the 256 amino acids that form the PrP protein. Studies of the genetics of sheep have shown three particular codons on the alleles that indicate TSE resistance or susceptibility. The codons are 136, 154 and 171 and are based on variations of amino acids at the location. Five different scrapie related alleles in sheep have been identified: codon 136 codes for either the amino acid valine (V) or alanine (A), codon 154 codes for either histidine (H) or arginine (R), codon 171 codes for glutamine (Q), argininne (R) or Histidine (H).

The three codons creates 15 genotypes classified into 5 categories of risk according to the British National Scrapie Plan (NSP). In all breeds the research suggests that the ARR allele is the most resistant to scrapie. The VRQ allele is the most scrapie susceptible. The ARQ/ARQ genotype is susceptible to some forms of scrapie and very susceptible to experimental BSE. Genetic selection is being used as the primary mean of scrapie control in the United Kingdom (UK).

The possibility to increase consumers' security in relation to the assumption of scrapie-free dairy products will represent a competitive advantage on the market. This capability at enterprises' disposal can fulfil the current consumers' needs for food safety and therefore will directly turn into a quality factor capable to promote sheep dairy productions on a wider market at both national and international level, providing support to the whole sector. The implementation of a scrapie-free assurance for ovine milk should also lead in the future to a reconsideration of the milk's payment parameters according to its safety, thus providing dairies with an additional parameter for the selection of suppliers in order to achieve a better risk management.

The main objective of this research was the development of analytical tools to assess and quantify scrapie risk in milk and the implementation of application by breeder organisations and dairy consortia throughout the production chain. The scientific work was performed by research Institution and Universities which prepared suitable analytical protocols for routine control purposes. The transfer of technology and knowledge from researchers to dairy technicians WAS possible by means of specific training courses.

The project will thus contribute to implementing EU policies by promoting competitiveness, standardisation, regulation and dissemination of best practices in the area of agriculture and more specifically sheep dairy industry. In terms of research and innovation, the objective of the new research and technology policy is to organise cooperation at different levels, coordinate national and European policies, encourage the networking of research teams and increase the mobility of individuals and ideas in order to reinforce European competitiveness. This project, given its European and trans-national nature, will contribute to such policies by bringing European SMEs from different sectors and countries in contact with Research Centres from across Europe. It will also contribute to create an European Research Area (ERA), the purpose of which is to establish a border-free zone for research, in which scientific resources will be better deployed to create more jobs and to improve Europe's competitiveness.

The exploitation of the results was carried out by the RISKSCRA consortium using two main approaches. The first approach concerns the internal exploitation while the second approach consists of a direct external exploitation of the project results. Application of the traceability guarantee system was extended from national to international market.

In particular, regarding the exploitation of the results, each partner implemented their own exploitation actions to take advantage of both the knowledge acquired throughout the project and its tangible results. The major result consists of 'Guidelines to set up traceability in cheese making factories with associated scrapie risk level'. These guidelines can integrate IAG dairy production rules and regulations on the PrP allelic profile control.

Potential buyers / users of RISKSCRA products are any sheep dairy enterprises interested in implementing safety and commercial strategies or improving the existing ones by complementing them with Riskscra control system.

These include:
(i) producer consortia interested in improving traceability guarantee system along dairy production chain to associate the scrapie-risk to the origin of milk;
(ii) breeder organisations interested in selection of genotype resistant to scrapie';
(iii) institutions interested in controlling sheep milk related to scrapie-risk.

Improving the quality of dairy products on the market increases the confidence of consumers and constitutes a basis for fair competition among dairy industries across Europe, again with added benefits for consumers. In addition, it enhances the European competitiveness in the global market. A further indirect application for breeder associations is the possibility to increase milk value by assuring the reduction of scrapie risk. The exploitation activities of RISKSCRA consortium consisted of promoting and marketing the tools developed within RISKSCRA. The IAGs and SMEs exploited the protocols carried out by RTDs to improve and manage their products' safety, thus increasing the consumers' interest and confidence towards ovine dairy products by offering assurance about scrapie risk's control.

We divided the actual outcome into two lines. During the first phase of the project RTDs defined a range of new protocols for RISKSCRA system use, in the second phase we transferred these protocols to IAG and SME technicians by appropriate training courses. The exploitation of project's outcomes started with the direct application of the methodologies at the IAG reference laboratories, which should be able to include the methods and the related parameters in the production control procedures and in the product label.

The project results may also bring forth the possibility to reconsider the milk payment criteria, currently based on other criteria (e.g. milk quantity, protein, fat, somatic cells and bacterial content) by adding the absence of scrapie-susceptible genotypes. In the long term, the project scientific and technical outcomes should be made available to many SMEs and applicable to different dairy sectors across the EU.

Related documents