Bovine spongiform encephalopathy (BSE) safety measures in Japan

Since the first identification of bovine spongiform encephalopathy (BSE) in Japan in September 2001, a series of safety measures was introduced by the Ministry of Agriculture, Forestry and Fisheries, the Ministry of Health, Labour and Welfare and the Food Safety Commission of the Cabinet Office. These measures included blanket BSE testing and removal of specified risk materials at slaughterhouses, surveillance of risk animals and a ban on the use of meat-and-bone meals and traceability on all farms. The Japanese experience over the past five years has shed light on several issues in countries that have a low BSE incidence.     

Estimating the trend of the French BSE epidemic over six birth cohorts through the analysis of abattoir screening in 2001 and 2002

A bovine spongiform encephalopathy (BSE) testing programme at the abattoir started in 2001 in France. A total of 5 281 293 bovines were tested in 2001 and 2002; 87 were found positive in 2001--37 per million (95% CI 30-46)--, whereas only 71 in 2002--24 per million (95% CI 19-30). Logistic regression models were run to compare the prevalence of BSE on successive birth cohorts, using a pair-wise method of controlling for age at testing; the prevalence on the first one, determined on animals slaughtered in 2001, was compared to the prevalence on the following one determined on animals slaughtered in 2002. Five models were performed in order to compare the birth cohorts preceding and following the months of June 1993 (i.e. July 92-June 93 birth cohort compared to July 93-June 94 birth cohort) (8.5 years old cattle), June 1994 (7.5 years old cattle), June 1995 (6.5 years old cattle), June 1996 (5.5 years old cattle) and June 1997 (4.5 years old cattle). The models were adjusted for the production type of cattle and the test used. The results showed a significant increase (OR = 2.31, 95% CI 1.08-4.9) of the BSE prevalence between the July 93-June 94 and July 94-June 95 cohorts, and then a significant decrease over the next two birth cohorts; the July 95-June 96 birth cohort was significantly less affected than the July 94-June 95 one (OR = 0.46, 95% CI 0.27-0.78), and the July 96-June 97 birth cohort was significantly less affected than the July 95-June 96 one (OR = 0.17, 95% CI 0.07-0.37). The increase in BSE prevalence between the July 93-June 94 and July 94-June 95 cohorts was in agreement with modelling studies, but needs to be confronted to the data on fallen stock at the national level. The decrease in BSE prevalence on the birth cohorts born after June 1995 was in agreement with the findings on the fallen stock in the western part of France and matches the implementation of the removal of specified risk materials (SRM) and dead animals from the processing of meat and bone meal (MBM) since June 1996.     

Effectiveness of the BSE interventions in Japan

Using a stochastic simulation model, we estimated the effectiveness of the three BSE interventions (SRM removal, post-mortem testing and cohort culling) in Japan, in terms of the amount of bovine ID50 that would be prevented from entering the human food supply and the number of life years that would be saved from resulting vCJD cases. The average reduction of the BSE load on the human food supply under SRM removal was 97% over the period from 2002 to 2009. The average reduction of the BSE load under most-mortem testing was 83% over the period from 2002 to 2007. The risk reducing effect of the three interventions combined was 99%. The maximum number of life years saved by the three interventions combined was 40.84 in 2006.     

Future directions in the European union for veterinary education as related to food-producing animals, with special reference to Greece

During the past 50 years, procedures for raising food-producing animals have changed. Intensification of food production was necessary to keep prices low and to fulfill market demands for the continuously increasing worldwide population. Intensification of farming procedures produced many new problems, some of which had a considerable impact on public opinion about how animals are raised and how food of animal origin is produced and preserved. "Man made diseases" of animals such as bovine spongiform encephalopathy (BSE); contamination of foods with dioxins either through contamination of animal feeds or from the environment; and increased microbial resistance to drugs used for treatment, for prophylaxis of animals from infectious agents, and for growth promotion are some well-known hazards of intensified farming. Veterinarians working on food-producing animals are faced with an increased demand for foods of high quality and safety in developed countries, and higher quantities in the rest of the world. These qualitative and quantitative changes indicate that they must adjust to these new conditions. They will be most successful if their education is adjusted to meet the challenges that the public has created for them through new concepts of the production of food of animal origin. One such concept is the production of foods under fully certified procedures from the farm to the consumer's table. Food safety measures protecting public health will better be achieved if the education of the future veterinarian includes the principles of Hazard Analysis Critical Control Points (HACCP) starting at farm level. This article provides some market-driven ideas in this direction for European Union (EU) countries, including Greece.     

Questionnaire analysis of BSE cases in France detected by active surveillance and the reasons for non-notification

A mandatory reporting system (MRS) was set up in France in December 1990 to detect animals showing clinical signs of bovine spongiform encephalopathy (BSE). Since June 2000, four active surveillance programmes dedicated to fallen stock and slaughtered cattle have been implemented to reinforce the MRS. The clinical status of the cases detected through these programmes was investigated to understand why the MRS had failed to detect them. Up to September 1, 2002, 181 cases had been analysed (126 fallen stock and 55 slaughtered cattle). Almost all the fallen stock cases were animals which had been showing clinical signs, and two thirds of them had shown signs which should have led to a suspicion of BSE. No clinical signs had been reported for two thirds of the slaughtered cattle cases and 10 (8 per cent) of the fallen stock cases.     

DNA条形码技术在食品溯源中的应用

现在食品安全越来越关注食品的可追溯性.近年来,DNA条形码作为食品溯源中一个潜在有效的工具得到迅速发展.本综述介绍了DNA条形码在食品安全尤其是在食品溯源中的应用,回顾了DNA条形码从概念的提出,到食品检测、食品溯源及防止食品商业欺诈中的应用.DNA条形码能够保障食品安全、防止商业欺诈,但距离真正的大规模应用,还有较长的路要走.     

Adjusted incidence risks of BSE in risk subpopulations of cattle in Japan

Immediately after the detection of the first case of BSE in 2001, the Japanese government introduced active surveillance targeting fallen-stock and all cattle slaughtered for human consumption. By the end of 2004, four million animals were tested with rapid tests under the passive and active surveillance. As a result 13 additional cases were detected. I focused on the 1996 birth cohort, in which nine cases of BSE were detected during 2001–2004, and estimated the prevalence of BSE infection of that birth cohort using maximum-likelihood methods. Using the estimated prevalence of infection as an input variable, I calculated the adjusted incidence risk of BSE by different ages and risk subpopulations (clinical-suspects, fallen-stock, sick-slaughter and healthy-slaughter animals). The adjusted incidence risk of BSE in sick-slaughter animals (animals showing clinical signs not compatible with BSE when slaughtered for human consumption) was 18.7 and 4.5–78.4 times higher than the incidence risk in fallen-stock and healthy-slaughter animals, respectively.     

Alternative BSE risk assessment methodology for beef and beef offal imported into Japan

The Food Safety Commission (FSC) of Japan, established in July 2003, has its own initiative to conduct risk assessments on food stuffs known as "self-tasking assessment". Within this framework, the FSC decided to conduct a risk assessment of beef and beef offal imported into Japan from countries with no previous BSE reports; thus, a methodology was formed to suit to this purpose. This methodology was partly based on the previous assessments of Japanese domestic beef and beef imported from U.S.A./Canada, but some modifications were made. Other organizations' assessment methods, such as those used for BSE status assessment in live cattle by the OIE and EFSA's GBR, were also consulted. In this review, the authors introduce this alternative methodology, which reflects (1) the risk of live cattle in the assessed country including temporal risks of BSE invasion and domestic propagation, with the assessment results verified by surveillance data, and (2) the risk of beef and beef offal consisting of cumulative BSE risk by types of slaughtering and meat production processes implemented and the status of mechanically recovered meat production. Other possible influencing factors such as atypical BSE cases were also reviewed. The key characteristic of the current assessment is a combination of the time-sequential risk level of live cattle and qualitative risk level of meat production at present in an assessed country.     

Food safety surveillance through a risk based control programme: approach employed by the Belgian Federal Agency for the Safety of the Food Chain

The principal responsibility of the Belgian Federal Agency for the Safety of the Food Chain (FASFC) is to guarantee the safety along the food chain. In order to accomplish this responsibility, the FASFC has developed an integrated official control program to check compliance with various regulations. The original methodology developed and applied by FASFC is presented. This methodology is based on risk evaluation, statistical tools and current scientific knowledge.     

A quantitative assessment of the risk of transmission of bovine spongiform encephalopathy by tallow-based calf milk-replacer

A Monte Carlo simulation model was constructed to assess the risk of BSE transmission to calves by calf milk-replacer (CMR). We assumed that any BSE infectivity in the CMR would be associated with the allowable levels of impurities in tallow used to manufacture the milk-replacer. Simulations used three different levels of impurities, six different distributions of the BSE infectivity titers of CNS tissues and with and without inclusion of specified risk material (SRM). Our results suggest that tallow-based CMR could have been responsible for some BSE infections in nearly all simulations. The reduction in the allowable impurities in tallow and the exclusion of SRM have greatly reduced--but have not eliminated--the risk of BSE transmission by CMR The results of the simulations are associated with much uncertainty.     

Real-time PCR和常规PCR方法快速鉴定肉骨粉中的牛源性成份

疯牛病是一种严重危害动物和人类健康的疾病,其病原朊病毒可以通过食物链进行传播,因此建立准确的检测牛源性成份的方法非常重要.我们采用常规PCR和Real-time PCR中的TaqMan技术建立了快速鉴定牛源性成份的方法,使用Chelex-100提取肉骨粉中的DNA,过程简单可靠仅需要20min左右.对不同含量的牛肉骨粉进行检测,常规PCR能够检测到的最低含量是0.001%,而Real-time PCR对相同的样品进行检测所得到的灵敏度更高,最高可达到0.0001%,两种PCR方法的鉴定过程都非常简单快速,各需要2 h左右.这两种方法可以根据各实验室的不同条件作为肉骨粉鉴别的常规检测方法.     

Animal health: foundation of a safe, secure, and abundant food supply

During the past century, reductions in animal diseases have resulted in a safer, more uniform, and more economical food supply. In the United States, the passage of the 1906 Federal Meat Inspection Act mandated better sanitary conditions for slaughter and processing, as well as inspection of live animals and their processed products. Following World War II, Congress passed the Poultry Products Inspection Act. Both acts are regulated by the Food Safety and Inspection Service (FSIS) of the US Department of Agriculture (USDA). The USDA's Animal and Plant Health Inspection Service (APHIS) is responsible for regulations governing the health of live animals prior to slaughter. This article is a brief overview of the ways in which the current predominance of zoonotics among emerging diseases underscores the importance of veterinary health professionals and the need for continued coordination between animal-health and public-health officials. Examples of intersections between animal- and public-health concerns include bovine spongiform encephalopathy (BSE) and Johne's disease, as well as extending beyond food safety to diseases such as avian influenza (AI). In the United States, we have in place an extensive public and private infrastructure to address animal-health issues, including the necessary expertise and resources to address animal-health emergencies. However, many challenges remain, including a critical shortage of food-animal veterinarians. These challenges can be met by recruiting and training a cadre of additional food-supply veterinarians, pursuing new technologies, collaborating with public-health officials to create solutions, and sending a clear and consistent message to the public about important animal-health issues.     

Public health education at Michigan State University

Many reports have highlighted the need for the veterinary profession to fill critical shortages of veterinarians in public health and food safety. Michigan State University's College of Veterinary Medicine offers educational programs within the professional veterinary curriculum, as well as graduate degree programs, to meet these societal needs. Within the scope of the professional veterinary curriculum, educational opportunities in public health include clerkships in veterinary public health and an innovative Web-based curriculum on judicious use of antimicrobials. For graduate degree programs, Michigan State University has a memorandum of understanding with the University of Minnesota for the Master of Public Health degree and an innovative Online Professional Master of Science in Food Safety degree program. A new option available is the opportunity for veterinary students to pursue the Master of Science in Food Safety concurrently with the DVM (DVM/MS in Food Safety). These educational programs will prepare graduates to meet societal needs in public health and food safety.     

A brief overview of food hygiene legislation

Following several animal disease outbreaks and food contaminant scandals in Europe in recent years, the European Commission adopted the White Paper on Food Safety in 2000. This White Paper contains a number of recommendations aimed to increase food safety, improve the traceability of food products and regain consumer confidence in the food industry. To this effect a package of new European legislation on food and feed has been prepared with the following characteristics: responsibility of food safety lies with the food business operator, while the competent authority of the Member State verifies correct implementation of the new rules. Production should be based on good hygienic practice and HACCP principles and products are subject to microbiological criteria and temperature limits. The legislation deals with all food and covers the entire food chain ("from stable to table"). The general framework of the new food hygiene legislation is explained. The General Food Law (Regulation (EC) No 178/2002) is discussed in more detail as well as the Regulations concerning food hygiene. The characteristics and requirements of each one of the three Hygiene Regulations is presented (Regulation (EC) No 852/2004, Regulation (EC) No 853/2004 and Regulation (EC) No 854/2004) with a particular emphasis on the changes in the new (horizontal) legislation as compared to the old (vertical) Directives. Implementing measures of the Hygiene Regulations have been published in the form of four Commission Regulations in December 2005. The implementing measures deal with technical issues often in great detail and became applicable at the same time as the Hygiene Regulations with effect of 1 January 2006. The major issues as laid down in the four Commission Regulations are presented. Finally, various guidance documents are mentioned. These documents are available on the Internet site (http//ec.europa. eu/food/food/biosafety/hygienelegislation/guide_en.htm) of DG SANCO and explain in plain language some of the topics of the Hygiene Regulations.     

Disposal of animal byproducts,dead and slaughtered animals

The current state of epidemiological knowledge about BSE clearly indicates that certain practices in carcass rendering had a significant impact on maintenance and spreading of BSE in the cattle population. This awareness did not come up spontaneously. As a reflection community legislation continuously developed and still does. The decisive move was done in the year 2000 by eliminating ruminant tissues with a high infectious potential with regard to BSE (specified risk material--SRM) from the human and animal feed chains. This step as well as the subsequent feed ban for all farm animals dramatically changed the logistical as well as the economical preconditions of the rendering industry. In fact the basic treatment (pressure cooking) remained almost unchanged. But instead of physically recycling the products they are nowadays predominantly used as an energy source in industry. In case of products that originate from the treatment of SRM burning is mandatory. These changes require a well adapted and intensified official supervision.     

Effect of tissue deterioration on postmortem BSE diagnosis by immunobiochemical detection of an abnormal isoform of prion protein

Surveillance for bovine spongiform encephalopathy (BSE) in fallen stock in Japan is conducted with a commercial enzyme-linked immunosorbent assay (ELISA) for mass screening, with Western blotting (WB) and immunohistochemistry performed for confirmation of the ELISA. All tests are based on immunological detection of an abnormal isoform of the prion protein (PrP(Sc)) in brain tissues, which have sometimes deteriorated by the time samples from fallen stock reach a diagnostic laboratory. To evaluate BSE surveillance procedures for fallen stock, we examined PrP(Sc) detection from artificially deteriorated BSE-affected bovine brain tissues with a commercial ELISA kit and compared the results with those of WB. The optical density (OD) values of the ELISA decreased with advancing deterioration of the tissues, whereas no reduction in the signal for PrP(Sc) was observed in WB, even when performed after 4 days of incubation at 37 degrees C. The progressive decrease in the OD values in the ELISA appear to be caused by a partial loss of the N-terminal moiety of PrP(Sc) due to digestion by endogeneous and/or contaminated microbial enzymes, and by the presence of ELISA inhibitors that are generated in deteriorated tissues. These results suggest that WB is the most reliable test for fallen stock, especially for cattle brains within decaying carcasses.     

BSE infectivity in jejunum, ileum and ileocaecal junction of incubating cattle

ABSTRACT: To establish bovine spongiform encephalopathy (BSE) public health protection measures it is important to precisely define the cattle tissues considered as specified risk materials (SRM). To date, in pre-clinical BSE infected cattle, no evidence of the BSE agent had been found in the gut outside of the ileal Peyer's Patches. This study was undertaken to determine when and where the pathological prion protein (PrPSc) and/or BSE infectivity can be found in the small intestine of cattle 4 to 6 months of age, orally challenged with BSE. Samples of the jejunum, the ileum and the ileocaecal junction from 46 BSE infected cattle, culled from 1 up to 44 months post infection (mpi) were examined by immunohistochemistry. Samples from cattle 8 mpi to 20 mpi were additionally studied by PTA Western blot, rapid tests, and by mouse (TgbovXV) bioassay. In doing so nearly all of the cattle, from 4 up to 44 mpi, had detectable amounts of PrPSc and/or infectivity in the distal ileum. In the distal ileum clear time-dependent variations were visible concerning the amount of PrPSc, the tissue structures affected, and the cells involved. BSE infectivity was found not only in the ileum and ileocaecal junction but also in the jejunum. The systematic approach of this study provides new data for qualitative and quantitative risk assessments and allows defining bovine SRM more precisely.     

The price of the precautionary principle: Cost-effectiveness of BSE intervention strategies in the Netherlands

Since 1996, bovine spongiform encephalopathy (BSE) in cattle has been linked to a new variant of Creutzfeldt-Jakob disease (vCJD), a fatal brain disease in man. This paper assessed the cost-effectiveness of BSE control strategies instituted by the European Commission. In a Monte Carlo simulation model, a non-intervention baseline scenario was compared to three intervention strategies: removal of specified risk materials from slaughter animals, post-mortem testing for BSE and the culling of feed and age cohorts of BSE cases. The food risk in the baseline scenario ranged from 16.98 lost life years in 2002 to 2.69 lost life years in 2005. Removing specified risk materials removal practices, post-mortem testing and post-mortem testing plus cohort culling reduced this risk with 93%, 82.7% and 83.1%. The estimated cost-effectiveness of all BSE measures in the Netherlands ranged from 4.3 million euros per life year saved in 2002 to 17.7 million euros in 2005. It was discussed that the cost-effectiveness of BSE control strategies will further deviate from regular health economics thresholds as BSE prevalence and incidence declines.