Scientific Opinion on the revision of the quantitative risk assessment (QRA) of the BSE risk posed by processed animal proteins (PAPs)
Olivier Andreoletti, Herbert Budka, Sava Buncic, John D Collins, John Griffin, Tine Hald, Arie Havelaar, James Hope, Günter Klein, James McLauchlin, Christine Müller-Graf, Christophe Nguyen-The, Birgit Noerrung, Luisa Peixe, Miguel Prieto Maradona, Antonia Ricci, John Sofos, John Threlfall, Ivar Vågsholm and Emmanuel Vanopdenbosch.
Acknowledgment
The Panel wishes to thank the members of the Working Group on the review of the QRA of the residual BSE risk of MBM: Amie Adkin, Olivier Andreoletti, Philip Comer, Christian Ducrot, Michael Gravenor, Matthias Greiner, James Hope, Christine Müller-Graf and Emmanuel Vanopdenbosch for the preparatory work on this scientific opinion.
Contact
biohaz@efsa.europa.eu
The cattle Bovine Spongiform Encephalopathy (BSE) risk posed by bovine derived Processed Animal Proteins (PAPs) in feed was estimated, the diagnostic methods and their sensitivity to detect animal proteins in feed and compared different risk assessment methods for animal proteins in feed was reviewed. It was concluded that the current global limit of detection for PAPs in feed is still considered to be 0.1%. Data related to BSE monitoring and PAP production in the European Union (EU) were considered. A model (EFSA QRA PAP model) was developed to study the magnitude of the total BSE infectivity in PAPs and in ruminant feed under a certain scenario assuming some specific cross-contaminations. On the basis of the 2009 BSE surveillance data in the EU, assuming a 0.1% contamination (the limit of detection for PAP in feed) with non-ruminant PAPs and according to the EFSA QRA PAP model, the total BSE infectivity load that could enter in cattle feed per year in the EU would be equivalent to 0.2 Cattle oral Infectious Dose 50% (Co ID50) (9 x 10-5 – 1.3 CI95%) (that would mean that less than one additional BSE infected cattle could be expected in the EU cattle population per year with an upper 95% confidence). The specific scenario described by the model and the related assumptions and uncertainties are discussed in this scientific opinion.
© European Food Safety Authority, 2011
Following a request from the European Commission (EC), the Panel on Biological Hazards (BIOHAZ) was asked to deliver a scientific opinion on the revision of the Quantitative Risk Assessment (QRA) of the Bovine Spongiform Encephalopathy (BSE) risk posed by Processed Animal Proteins (PAPs)[1].
The feed ban is the key animal health protection measure against Transmissible Spongiform Encephalopathies (TSEs) and consists of a ban on the use of animal proteins in feed for farmed animals. Scientific data link the spread of BSE to the consumption of feed contaminated by the infected ruminant proteins. Based on these findings a ban on the feeding of mammalian PAPs to cattle, sheep and goats was introduced in July 1994. The ban was expanded in January 2001 with the feeding of all PAPs to all farmed animals being prohibited, with certain limited exceptions. Any presence of prohibited constituents of animal origin in feed is considered as a breach of the feed ban i.e. the zero-tolerance.
The overall decrease in the numbers of BSE cases across the European Union (EU) (about 2,167 BSE cases in 2001 in the EU 15, compared to 125 cases in the 2008 and only 45 up to the end of November 2009 in the EU 27) clearly demonstrates a continuous positive trend in the eradication of the disease. Therefore the EC asked the European Food Safety Authority (EFSA): i) to review and update the scientific input data of the current EFSA QRA model (“EFSA QRA Report 2004 on quantitative assessment of the residual BSE risk in bovine-derived products.”)[2] ; ii) if needed, to review the methodology and update the current QRA model; and iii) to review the cattle BSE risk posed by bovine derived PAPs with respect to the residual BSE risk, based on the outcome of the QRA.
The BIOHAZ Panel addressed the mandate by: i) reviewing the diagnostic methods and their sensitivity to detect animal proteins in feed; ii) comparing different risk assessment models for animal proteins in feed; and iii) updating the scientific input data and the previous EFSA QRA model under a specific scenario. Moreover, some considerations about Atypical BSE were taken into account.
It was concluded that the current global limit of detection for PAPs in feed is still considered to be 0.1%. The structure of the EFSA QRA model was considered to be still suitable for the purpose of the mandate received and an updated version of that model (called EFSA QRA PAP model) was developed to answer the specific terms of reference of the mandate.
The EFSA QRA PAP model relies on the continuation of the current Specified Risk Material (SRM) policy and TSE monitoring system. It also assumes that only Category 3 Animal By-Product material is allowed to enter in PAP produced from ruminant material. The model is based on a specific scenario and on specific assumptions like the homogeneous mixing of the material for feed production. While conservative values were used, uncertainties of certain parameters were identified; changes in scientific knowledge would require an adjustment of the model. The model calculations are based on the presently available data, including unofficial ones, about PAP production communicated directly by industry; changes in PAP and feed production would require adjustment of the model input data.
On the basis on the 2009 BSE surveillance data, assuming a 0.1% contamination (which is the limit of detection for PAPs in feed) with non-ruminant PAP and according to the EFSA QRA PAP model, the Panel concluded that the total BSE infectivity load that could enter in cattle feed per year in the EU would be equivalent to 0.2 Cattle oral Infectious Dose 50%[3] (Co ID50) (9 x 10-5 – 1.3 CI95%) (that would mean that less than one additional BSE infected cattle could be expected in the EU cattle population per year with an upper 95% confidence).
It was highlighted that considering the many uncertainties related to Atypical BSE (prevalence, tissue distribution of the infectious agent, efficacy of rendering process for agent inactivation) the risk of Atypical BSE transmission through PAPs cannot be assessed but should not be disregarded.
It was recommended to continue the development of analytical methods to improve the limit of detection of animal proteins in feed and to take into account the risk of (re-)emergence of TSE in cattle in case the use of some mammalian PAPs for feeding animals should be reintroduced. Moreover, in case of modification of the mitigation measures against BSE the assessment should be updated.
Furthermore, the BIOHAZ Panel recommended to: i) collect specific data related to the PAP production and distribution system; ii) expand specific knowledge related to Atypical BSE (in particular as regards to prevalence, pathogenesis in natural host, capacity to propagate in other animal species and resistance to inactivation processes applied in rendering plants); and iii) to revise the assessment when appropriate information on Atypical BSE becomes available.
Bovine Spongiform Encephalopathy (BSE), quantitative risk assessment, Processed Animal Proteins (PAP), Cat 3 Animal By-Products
