In addition, a literature review prepared by Dr. Annel Greene and Dr. Paul Dawson, Clemson University, that included a review of over 930 references with 350 references cited on the safety of animal fats was presented. Greene and Dawson are the director and associate director respectively of the Animal Co-Products Research and Education Center that was officially dedicated and initiated July 1, 2005, at Clemson University. The Fats and Proteins Research Foundation (FPRF) is the center’s founding sponsor.
Dr. Graham Clarke, director of the Animal Industry Division of the Branch of Agriculture and Agri-Food Canada, presented Canada’s plan for practical ways to dispose of specified risk materials (SRMs) and to propose a national plan to do so. Using the recommendation of the Intervention Team of Animal Health Experts from June 2003 that SRM removal from the feed chain would be an effective means to reduce infectivity in meat and bone meal, the Canadian government has proposed a regulation to remove all SRMs from feed and fertilizer supply chains. A major study is near completion that identifies the economic, biosecurity, and affect on all stakeholders in each of the Canadian provinces. The actual regulation has not been finalized.
Dr. Linda Detweiler, former coordinator of the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service surveillance, prevention, and education activities for BSE and well known to the rendering industry, presented a review of the estimated volumes of SRMs and their basic composition.
A summary of the work completed by Bruce Miller of Penn State University comprising the fats, proteins, and animal tissue biomass activities was presented, which included utilizing the animal tissue by-products as feedstocks in coal-fired fluidized bed combustion boilers. Animal fats and greases compared very competitively in energy densities to fuel oils. The animal proteins and animal proteins containing fat, when compared to baseline coal, were statistically indistinguishable in energy densities. The work was completed with a pilot-scale facility with plans to complete a feasibility study and design for a full-scale plant. The overall objective is to evaluate methods to utilize animal tissue, diseased animals and carcasses, dead and downer cattle, and perhaps SRMs.
Dr. Ulrich Kihm, chief veterinary officer of Switzerland, in a review of the transmissible spongiform encephalopathy (TSE) diseases and BSE disease, referenced the antimortem diagnostic difficulties with current detection procedures. He noted that BSE detection was not possible during the incubation period prior to clinical symptoms and shortly before the end of the incubation time. The emphasis, in my opinion, degraded current surveillance programs without a reference to the assay procedures available or the full explanation of the surveillance programs in existence.
An important element of public perception regarding BSE is the extremely low incidence, if any, in the U.S. and Canada cattle population. Over the years, over a half million cattle have been examined in the two countries. There should be no de-emphasis of the efforts expended in demonstrating to the consuming public that the best scientific-based surveillance programs are, in effect, providing current data for an extremely low incidence, if any at all.
Dr. Ray Bradley addressed the subject of rendering in the context of using tallow as a feedstock for biodiesel. He emphasized that no one has conclusively demonstrated that any tallow, including that filtered to contain 0.15 percent or less insoluble impurities, is a factor in the occurrence of BSE. Nonetheless, a zero risk cannot be proven; therefore, he suggested the aim should be to achieve effective risk reduction approaches. But, if we assume the current published data are adequate, the risk of tallow from SRM tissue is safe for biodiesel. The risk, Bradley said, could be lowered by the removal of SRM from the starting material for rendering. He also suggested pressure cooking at three bar and reducing the level of insoluble impurities in tallow from 0.15 percent to 0.02 percent. It is important to reference his conclusion that current knowledge indicates that filtered tallow derived from any BSE or scrapie-infected source contains no detectable TSE infectivity, no matter what rendering method is used to prepare it.
Dr. David M. Taylor emphasized that TSE infectivity is not usually present in crude tallow even when it is produced under worst-case conditions, but as a true scientist, added that it would be naive to suggest that infectivity could never be present in tallow. Considerable data was presented on the reduction of TSE infectivity of various processing procedures and the concentration on biodiesel production. He cited Dr. Martin Alm’s article in the October 2004 issue of Render magazine. Alm is a new member of the FPRF Research Committee.
Dr. Neil Cashman, University of British Columbia, is a neurologist-neuroscientist concentrating in neurodegeneration and neuroimmunology. His presentation was a historic review of the prion diseases in both human and animal forms. Prions were described as being somewhat like crystalization as well as a misfolding of protein. These abnormal protein molecules do not require DNA or RNA to replicate, but once formed, continue to produce abnormal prions in place of the normal replication. The human form of variant Creutzfeldt-Jakob disease (CJD) has been diagnosed in approximately 150 humans, with one in Canada and one in the United States.
Cashman likewise discussed a very extensive research program in Canada to specifically address core projects in BSE, chronic wasting disease/scrapie, CJD, structure of prion, biocontainment and structural biology, and a risk assessment model. The project is a seven-year proposal with a price tag of $5 million per year for the first four years.
A noble commitment to a mystifying disease complex; however, a commitment that may be duplicating, verifying, or conflicting with known science or research underway at various institutions. The mystic and myths associated with BSE and the other TSEs have opened tremendous opportunities for researchers to acquire funding and tenured positions. Cashman was apprised of the research initiatives in the planning process at the U.S. Environmental Protection Agency, and encouraged collaboration.
A research colleague of Cashman’s, Dr. Jennifer Griffin, discussed her research in progress to identify prions in biodiesel with the Western blot and gel electrophoresis assays. A series of speakers addressed their research protocols (none currently initiated) to pursue the testing of TSE infectivity using the rendered feedstocks in biodiesel and BSE. Most involved spiking with known TSE infective material, thus assuming that tallow could contain BSE. Further, the proposals referenced TSE without defining the specific TSE. Analysis procedures and inactivation varied among the TSEs, thus extrapolation between them is not appropriate. It was suggested that microfiltration might be an option to remove all prion proteins from biodiesel and/or wastewater. But if tallow does not contain prions, then why?
Via teleconference, Greene and Dawson presented a 153-page draft report that summarized the critical review of the literature addressing the safety of animal fats for biodiesel production. The review addressed the areas of bacteria, viruses, parasites, microbial toxins, biogenic amines, mycotoxins, and chemical contaminants. The effectiveness of rendering supplemented by the rendering process controls was referenced throughout the presentation as the most economic, biosecure, and environmentally secure procedure for processing animal co-product material.
Dr. Paul Brown provided his review and summary: “We are here to discuss a miniscule risk of using SRMs or tallow as feedstock for biodiesel. A very simple answer is to throw it away. But it is 1.1 million tons!” He offered four recommendations:
• Exclude a short list of SRMs, which would include brain and spinal column. His assessment indicated that the short list exclusion provides the same infectivity reduction to tallow as the long list exclusion.
• Conduct a renewed research protocol for rendering inactivation.
• Develop PrPTSE and bioassays for multiple protocols and biodiesel production steps.
• Prove that biodiesel is sterile prior to pre-combustion.
In effect, Brown’s last recommendation could provide researchers with tenure of projects. It also seems as if the mystique of BSE has provided funding to do so. But in the total review, prion presence or the infectivity of tallow has not been demonstrated. Therefore, as with nearly all issues associated with the TSEs, “absence of evidence is not evidence of absence.” In a time in which biofuels offer so much opportunity to benefit our environment with fewer pollutants, wouldn’t research be better directed towards enhancing their usage instead of exploiting barriers and creating concerns for their use?
The draft copies of the presentations and the document drafts are being made available for review on ATF’s Web site at www.atfcan.com. Comments were being received until August 1, 2005, after which time the final reports will be completed and made available.
August 2005 Render