: e. ,’ .( b’ ‘-A TSE RISK ASSESSMENT FOR USING MEAT-AND-BONE-MEAL AS FUEL FOR THE PRODUCTION OF CEMENT Ray Bradley CBE Private BSE Consultant Guildford UK E-mail: [email protected] inspection purposes only. Consent of copyright owner required for any other use. !,:: c : :) h:@’ {a, .,‘, I EPA Export 25-07-2013:14:35:46 A TSE RISK ASSESSMENT FOR USING MEAT-AND-BONE-MEAL AS FUEL FOR THE PRODUCTION OF CEMENT Ray Bradley CBE EXECUTIVE SUMMARY A risk assessment has been conducted to assess direct and indirect risks from transmissible spongiform encephalopathy (TSE) agents to public and animal health as a result of changes to the fuel used by Lagan Cement Ltd, Killaskillen, Co. Meath, Republic of Ireland to produce cement. The stimulus for this risk analysis is a result of Lagan Cement making an application to the Department of Agriculture, Food and Rural Development to use lawfully produced meat-and-bone-meal (MBM) derived from rendering Irish animal by-products including specified risk materials (SRM) as a fuel for the production of cement. SRM comprises the tissues from a bovine carcase that carry a BSE risk and tissues from sheep and goat carcases with the highest risk of being infected with a scrapie agent. The risks to be assessed are those to public and animal health directly or indirectly through the food or feed chains. The BSE agent from cattle is a human pathogen but scrapie agents are not. The assessment has been conducted following a site visit, consultation of relevant legal and scientific documents and official reports of expert committees and quantitative risk assessors and using the wide experience of the author. The assessment has been conducted by investigating the TSE risks that might derive from the animal starting material permitted into the starting material for rendering in Ireland (the SOURCE); the effectiveness of rendering as used in Ireland to inactivate any TSE infectivity they may contain and the ability of cement manufacture to combust the MBM and destruct any remaining TSE infectivity (collectively the PROCESS). A third factor (USE) is not For inspection purposes only. relevant to this assessment becauseConsent there of copyright is onlyowner requiredone use for any option other use. for cement (for building) that is unchanged, no matter what fuel is used. Furthermore, as the report will show, there is no risk beyond negligible from the point at which the MBM in cornbusted and destroyed. e In regard to SOURCE, under European law MBM in Ireland can be produced in theory from animal materials of three Categories: 1, 2 and 3. Category 2 and Category 3 material does not present a TSE risk, so the MBM produced from such material does not present a TSE risk either and is not considered further. Category 1 material does present an actual or potential TSE risk. The level of risk in the European Union (EU) is variable depending on the nature of the starting material permitted into rendering by national law. In Ireland this is very strictly - controlled and eliminates the--,highest TSE risk material, namely the whole carcase and.all tissues and organs from those animals clinically suspected and confirmed to have BSE (passive surveillance). Targeted active surveillance and ‘Rapid’ testing of risk animals over 24 months old and slaughter cattle over 30 months old enables unsuspected cases of BSE to be detected beyond those identified by passive surveillance alone. The BSE infectivity actually present in the SRM from this additional population is likely to be less than that present in clinically confirmed cases because they would mostly be at an earlier stage of incubation. Thus, the BSE risk in Category 1 animal by-products in Ireland is limited to infectivity in a small proportion of the total SRM that come from infected animals that are in the early or mid stages of the incubation period and have not been, or cannot be, identified 0 2 EPA Export 25-07-2013:14:35:47 clinically, or by ‘Rapid’ testing. A small but declining risk in SRM starting materials might also result from the inclusion of potentially infected tissues from slaughter cattle cross contaminated with infected tissues from an adjacent rare slaughter animal that tests positive for BSE. The level (titre) of infectivity in the SRM from infected cattle that have tested negative for BSE is not known with certainty but is expected to be at least 10 times lower than that in the brain of a positive animal, In Ireland the BSE epidemic is past its peak, the age of positive animals is increasing so the amount of infectivity in SRM is declining year on year. SRM from goats presents a very low risk from scrapie agents as the incidence of scrapie in goats is very low in Ireland though not many have been tested. Because a recent case of BSE in a goat in France has been identified there is a much increased active surveillance for TSE in goats throughout the EU. Even in sheep, though the incidence of scrapie is higher than in goats it is still relatively low. BSE has not been detected in sheep in any country of the world to date (March 2005). Scrapie may also be declining because of selection of resistance alleles in breeding rams and because flocks in which scrapie is diagnosed must now under EC law either be culled or genotyped with susceptible sheep eliminated. It is too early to determine the extent of scrapie in sheep in any country because active surveillance has not been in existence for long enough and is as yet incomplete. Transmissible mink encephalopathy, chronic wasting disease, TSE of captive wild ruminants and domestic cats and TSE in native- born captive wild FELIDAE do not exist in Ireland and present no TSE risk in starting materials for rendering. Thus it is concluded that some Category 1 material in Ireland will contain TSE infectivity but the amount is small and declining and the titre of infectivity within it is relatively low. In regard to PROCESS and rendering in Ireland all rendering plants operate to the same standard and use pressure cooking (particle size I 50 mm, 133” C, 3 bar, 20 min) that reduces BSE infectivity by 2 3 logs. Furthermore, the rendering parameters adopted by law are enforced by the Department of Agriculture and are sufficiently robust to inactivate the vast majority, if not all the input infectivity in the resulting MBM. There is thus a low (and decreasing) likelihood that SRM ForMBM inspection in purposes Ireland only. could contain significant levels of Consent of copyright owner required for any other use. infectivity in more than a small proportion of the total amount of MBM produced per annum (150,000 tons). In regard to PROCESS and cement manufacture the EC has declared that Category 1 MBM must be incinerated (and the ashes buried in a licensed landfill facility) or be co-incinerated. Cement manufacture is one authorised means for disposal by co-incineration though plants that employ MBM as a fuel must be licensed to do so by the appropriate authorities. Collectively all scientific studies relating to TSE agent inactivation by dry heat indicate complete destruction at temperatures over 600” C and especially in the vicinity of 1000” C and higher. All end products have been shown to-be .biologically inert over 1000” C. The MBM used as a fuel for cement manufacture will be completely combusted either directly in the flame at a temperature in excess of 2000” C or at 1400” C in the kiln. Exposure to these destructive temperatures follows pre-heating in cyclones at about 850” C and during a total transit time of c. 20 seconds for the raw (mineral) meal and c. 8 seconds for gases. The particle size of the MBM (measured in pm) will be the same as that for coal, and the raw (mineral) meal and will have a consistency of a fine powder. Such a small size will enable rapid heat penetration and immediate combustion in the flame or in the kiln itself thereby securing complete destruction. After combustion the newly formed clinker is pulverized into a 3 F EPA Export 25-07-2013:14:35:48 .‘, . _. , ; ,_i.- F powder and this process is likely to destruct any inorganic replicas of sheeted PrP (fossil templates) that some have suggested might enable replication of PrP !’ if introduced into animals or man, With current knowledge it is inconceivable that combusting Irish Category 1 MBM or any other category of.&3M could contain any level of infectivity above negligible. Therefore the TSE risks to humans, animals and the environment are regarded as negligible if the methodology outlined in this report is followed. CONCLUSION The burning of Irish MBM, including SRM MBM as a fuel for the manufacture of cement under the general conditions described in this report present a negligible TSE risk for humans, animals or the environment. For inspection purposes only. Consent of copyright owner required for any other use. EPA Export 25-07-2013:14:35:48 ABBREVIATIONS GLOSSARY AND DEFINITIONS BSE Bovine spongiform encephalopathy BSESAC Bovine Spongiform Encephalopathy (BSE) Scientific Advisory Committee of the . Republic of Ireland DNV Det Norske Veritas (a company specialising in quantitative risk assessment) EC European Commission DAFRD Department of Agriculture, Food and Rural Development (Ireland) Department of Agriculture - DAFRD Ireland i/C Irma-cerebral (inoculation directly into the brain) MAFF Ministry of Agriculture, Fisheries and Food UK MBM Meat-and-bone-meal OIE Office International des Epizooties PrPsc Prion protein (disease specific form only found in TSE-infected hosts). PrPc is the precursor of PrP’” and occurs in uninfected and infected hosts).