A comparison of the risk of bovine spongiform encephalopathy infectivity in beef from cattle younger than 21 months in Japan with that in beef from the United States as assessed by the carcass maturity score

After the detection of the first case of bovine spongiform encephalopathy (BSE) in the United States in December 2003, the Japanese government halted all imports of U.S. beef. The BSE risk in beef is partly dependent on the slaughter age of the cattle from which it is derived. In Japan, all cattle 21 months old and older are screened using a rapid diagnostic test, while in the United States, routine BSE testing is not done at any age of slaughter cattle. In the United States, there is no nationally mandated cattle identification system that enables cattle younger than 21 months to be identified. Therefore, all beef potentially produced for export to Japan must be from cattle that are age verified as younger than 21 months old or be classified by the U.S. Department of Agriculture using a carcass maturity score, which in turn is related to the age of the animal from which the beef is derived. After consulting the Food Safety Commission, the Japanese government decided on 12 December 2005 to allow importation of beef from the United States derived from cattle with a carcass maturity score of < or =A40 and from which specified risk materials are removed. In this study, a stochastic model was used to simulate the interval of time from slaughter to the predicted clinical onset of BSE in an infected animal. A simulation result, based on the assumption that the BSE prevalence is equivalent in the two countries, revealed that there was no increased risk of BSE infectivity in beef coming from carcasses with a maturity score of < or =A40 in the United States, compared with beef from cattle younger than 21 months slaughtered in Japan.     

Assessment of the impact of cattle testing strategies on human exposure to BSE agents in Japan

In Japan, cattle screening tests for BSE are conducted at slaughterhouses for surveillance purposes and as a meat safety measure, but the public health impacts of such testing and the subsequent removal of positive animals from the food chain have not been quantitatively assessed. We evaluated the influence of removing specified risk materials and the alternation of age limits for testing cattle at the slaughterhouse on human exposure to the BSE agent in Japan by constructing a probabilistic risk model. A stochastic model using Monte Carlo simulation was constructed in order to estimate the BSE infectivity destined for the food chain from a single BSE-infected animal at slaughter. The impact of different testing strategies and risk material removal were then compared. Murine intra-cerebral ID50 (m.i.c. ID50) units were used as units for BSE infectivity. Sensitivity analysis was conducted for key input variables by changing values within plausible ranges. The expected fraction of BSE-infected cattle presented for slaughter that would be detected by screening tests was 20%, even if all slaughtered cattle were tested. The removal of risk materials reduced the median value estimate of infectivity destined for human consumption by 95%. Cattle screening tests reduced the infectivity further, but reduction efficacy did not differ among the various testing strategies. Sensitivity analysis indicated that the characteristics of BSE infectivity accumulation during the incubation period, extension of the incubation period, and lowering the detection limit of screening tests had no significant impact on relative infectivity reduction, which remained stable irrespective of testing strategy or changes in these parameters. This study suggests that the impact of changing the age limit for testing cattle on beef safety is small, provided that the removal of risk materials is conducted properly.     

STRATEGIES FOR THE CONTROL OF BSE AND SCRAPIE

Transmissible Spongiform Encephalopathies, or Prion diseases, are fatal neurodegenerative diseases that affect both humans and animals. Examples include Creutzfeldt-Jakob disease (CJD) in humans, Bovine Spongiform Encephalopathy (BSE) in cattle and scrapie in sheep and goats. They are characterized by a long incubation period, ranging from months to years, and a variable length clinical course, both determined by the particular infection and the species involved. Some 170,000 cattle in the UK have been diagnosed with BSE and have been destroyed. In the rest of Europe there have also been cases of BSE, though the numbers involved are much lower. The recent potential link between BSE and a new variant form of CJD has highlighted the importance of controlling both BSE and scrapie in Ireland. Control of the disease in both cattle and sheep is complicated by the long incubation period, the lack of suitable tests and the general lack of detailed information in relation to the biology of the disease. Factors that must be considered in designing an effective control strategy include (1) better understanding of the epidemiology of the disease, (2) developing rapid and reliable tests for the disease, (3) introducing a suitable surveillance system for both BSE and scrapie, (4) minimizing the consequences for farmers that have BSE-infected animals, and (5) implementing and monitoring legislation to prohibit the spread of potentially infectious material. Each of these areas is discussed and it is proposed that the introduction of best available technology in both the diagnosis and surveillance of the national herd could form the basis for an effective program against animal prion diseases.     

疯牛病令全球惶恐不安

<正> 随着全球经济日益走向一体化,世界各国愈来愈密切地成为一个荣辱与共的整体。当人类把动物圈起来,用统一的饲料喂养动物,让动物最大限度地繁殖和生长时,动物本身的灵性消失,变的像工业品一样整齐划一。人类陶醉在自己的科技中沾沾自喜时,这种对生命敬畏的丧失,最终导致惩罚落到人类自己头上。动物疾病广泛传播的危机,造成粮食     

New directions in foodborne disease prevention

Food safety is an important part of public health linking health to agriculture and other food production sectors. For over a century, developments in food production and new control philosophies have contributed to food safety systems in most developed countries perceived by many to be efficient in the prevention of foodborne disease. Nevertheless, a number of problems still remain dominant, one of these being the high level of foodborne microbiological diseases which seem, for some pathogens, to have increased over the last decades. Although there is an urgent need for better foodborne disease data in most countries, the paper attempts an analysis of the background to these problems using available data to illustrate the developments for some of the major foodborne pathogens. Some of the shortcomings of present food safety systems are discussed, as are new principles to improve food safety strategies. A new paradigm for the integration of research data, food-control monitoring, epidemiological investigations and disease surveillance in a renewed effort to manage and lower foodborne risk is presented. Within this paradigm, the development of an interdisciplinary approach with direct interaction between surveillance and risk analysis systems is described as a potential basis for improved foodborne disease prevention. Specific consideration is given to the situation in developing countries, suggesting a leap forward past the experience of noncollaboration between the disciplines in many developed countries. Today, food safety is one of WHO's top 11 priorities and the Organisation calls for more systematic and aggressive steps to be taken to significantly reduce the risk of microbiological foodborne diseases. Dealing with this challenge is one of the major challenges for the 21st century in regard to food safety, implying a significant redirection of food microbiology efforts in many parts of the world.     

Evaluating the technical feasibility of aflatoxin risk reduction strategies in Africa

Public health interventions must be readily accepted by their target populations to have any meaningful impact and must have financial and infrastructural support to be feasible in the parts of the world where they are most needed. At the same time, these interventions must be assessed for potential unintended consequences, either to the environment or to human health. In this paper, we evaluate the technical feasibility of interventions to control aflatoxin risk, to be potentially deployed in parts of Africa where aflatoxin exposure poses a significant public health concern. We have applied a conceptual framework for feasibility to four interventions, one associated with each of four different stages of aflatoxin risk: biocontrol (pre-harvest), a post-harvest intervention package (post-harvest), NovaSil clay (dietary), and hepatitis B vaccination (clinical). For each intervention, we have assessed the following four components of technical feasibility: (1) characteristics of the basic intervention, (2) characteristics of delivery, (3) requirements on government capacity, and (4) usage characteristics. We propose ways in which feasibility of each intervention is currently high or low from the perspective of adoption in Africa, how public education is crucial for each of these interventions to succeed, and how to align economic incentives to make the interventions more suitable for less developed countries.     

Salmonella surveillance and control for finisher pigs and pork in Denmark — A case study

Salmonella can either be controlled pre-harvest, post-harvest or by a combination of both approaches. This paper describes the lessons learned in Danish Salmonella surveillance and control programme for finisher pigs and pork. Initially, main focus was on pre-harvest initiatives and correct identification of herds with respect to the risk for Salmonella that they represented. However, an analysis of risk-mitigating actions applied along the chain from stable to table showed that it would be more cost-effective to deal with Salmonella on the abattoirs than in the herds. This knowledge moved focus from pre- to post-harvest without giving up on pre-harvest surveillance. First of all, this meant increased attention on slaughter hygiene and individual interventions in the abattoirs. In brief, we learned that for a programme to be successful it must be based on standardised methods for sampling and testing to be able to evaluate and compare performance of the programme. More specifically, meat-juice samples taken from finisher pigs at the time of slaughter are an effective way of identifying high-risk herds for Salmonella. In addition, a penalty system might act as an incentive for farmers to deal with Salmonella in their herd. Additionally, common targets for all abattoirs allowing for unique control solutions should be adapted. Finally, decontamination techniques like hot water decontamination are a feasible way of dealing with high-risk pigs (Level-3 pigs). The current prevalence in Danish pork is around 1.2%, and a target is set to < 1.0% to be reached by the end of 2013. The experience obtained by use of the Danish programme might be used to develop and implement appropriate types of surveillance programs as well as risk-mitigating measures in other countries.     

Comparative histological studies of mechanically versus manually processed sheep intestines used to make natural sausage casings

The natural sausage casings industry is large and worldwide, and casings prepared from the small intestine of sheep form a large part of it. Food safety authorities in several countries have been concerned about the risk to consumers from the bovine spongiform encephalopathy (BSE) agent. Although this agent could enter the European small ruminant population via infected feed, there is no evidence that it has. Because the BSE agent introduced experimentally into sheep and goats has a tissue distribution very similar to that found in animals with natural cases of scrapie, the agent would likely be found in the intestine and lymph nodes of some infected sheep from an early age. When natural casings are prepared from the intestine, the ileum (known to be infected in animals with natural cases of scrapie) is removed and the intestine is cleaned such that the inner (tunica mucosa) and outer (tunica serosa and tunica muscularis) layers are removed, leaving only the submucosa. There are two main methods for cleaning the intestine: manual and mechanical. The cleaning efficiency of these two methods was examined in the commercial environment as practiced on healthy sheep considered fit for human consumption in Turkey and Great Britain. The investigation involved a qualitative and quantitative histological approach. There was no significant difference in cleaning efficiency between the two methods, although there was some variation. No Peyer's patches or residues of them were found in any part of the cleaned casings. This finding is important because in sheep infected with transmissible spongiform encephalopathies (TSEs) Peyer's patches are likely to contain a major part of the intestinal infectivity. No serosa was found in any casing, but some residual mucosa and muscularis was retained, with more of the former than the latter. The results indicate that the cleaning efficiency of the two methods was broadly equivalent, that there was significant removal of tissue that could promote TSE infection, and that TSE risk reduction likely would be achieved by both methods, although this probability could not be quantified by the methods used in this study.     

Rheological interactions between Lallemantia royleana seed extract and selected food hydrocolloids

BACKGROUND: Lallemantia royleana (Balangu) is a mucilaginous endemic plant which is grown in different regions of world. The flow behaviour of Balangu seed extract (BSE) and its mixture with xanthan, guar and locust bean gums at 1:3, 1:1 and 3:1 ratios, in addition to control samples (0% BSE), were evaluated. To describe the rheological properties of samples, the power law model was fitted on apparent viscosity–shear rate data. To evaluate the interaction between BSE and selected hydrocolloids in dilute solutions, the relative viscosity was also investigated. RESULTS: There was no significant difference between the consistency coefficient of guar and locust bean solutions and their blends substituted with 250 g kg^?1 BSE. The BSE–xanthan mixture at 1:3 and 1:1 ratios had consistency index equal to xanthan solution. BSE–locust bean gum at all ratios, BSE–xanthan at 1:3 ratio and BSE–guar gum at 1:1 and 3:1 ratios indicated relative viscosity lower than values calculated assuming no interaction. The intrinsic viscosity value of BSE was determined 3.50 dL g^?1. CONCLUSION: The apparent viscosities of BSE, selected hydrocolloids and their blends were the same at a shear rate of 293 s^?1 and the commercial gums can be substituted by 250 g kg^?1 and 500 g kg^?1 BSE. Copyright © 2011 Society of Chemical Industry     

借鉴国际经验完善我国食品安全风险监测制度的探讨

食品安全风险监测是在风险分析原则基础上,由国际组织倡导并在许多国家取得成功的一项食品安全风险管理工作。我国自2010年以来开始建立并实施国家食品安全风险监测制度,目前在建立制度、部门参与、计划和方案制定以及结果应用等方面还存在不少欠缺和不足。本文借鉴了国际组织和先进国家的经验,从风险监测的目的、特点和需求出发,提出了建立风险监测工作规划,进一步改进参与机制和信息沟通利用机制,并对食源性疾病监测工作提出了具体改进建议。     

Impact of small scale fermentation technology on food safety in developing countries

Fermentation is one of the oldest technologies used for food preservation. Over the centuries, it has evolved and been refined and diversified. Today, a variety of food products is derived from this technology in households, small-scale food industries as well as in large enterprises. Furthermore, fermentation is an affordable food preservation technology and of economic importance to developing countries. In the report of an FAO/WHO Workshop (FAO/WHO, 1996), fermentation was reviewed and the nutritional and safety aspects of fermentation technologies and their products were assessed. Fermentation enhances the nutritional quality of foods and contributes to food safety particularly under conditions where refrigeration or other foods processing facilities are not available. Hazard Analysis and Critical Control Point (HACCP) studies of some fermented products have demonstrated that depending on the process and the hygienic conditions observed during preparation, some fermented foods, e.g. togwa prepared in Tanzania, may pose a safety risk. Fermented foods must therefore be studied following HACCP principles and small-scale food industries and households must be advised on the critical control points of fermentation processes and the control measures to be applied at these points. This paper reviews the risks and benefits of fermentation and demonstrates the application of the HACCP system to some fermented foods in developing countries.     

CURRENT STATUS OF BOVINE SPONGIFORM ENCEPHALOPATHY-A REVIEW

Bovine spongiform encephalopathy (BSE) is a fatal brain disease of cattle which is presumed to have originated from feeding meat and bone meal (MBM) manufactured from rendered scrapie-infected sheep. More than 170,000 cases of BSE have been identified in UK cattle since it was specifically diagnosed in 1986. Most are in dairy herds. This paper reviews the background of the disease, changes in rendering in the United Kingdom which appear to have led to the development of BSE in cattle, characteristics of the disease, the disease-causing agent (prions), related prion diseases in other species, the impact of genetics on prion disease, prion strains, species barriers to transmission, risk of Creutzfeld-Jakob disease to humans, inactivating prion infectivity, and tallow and gelatin production and safety. Efforts at controlling the disease in the United Kingdom and preventing the disease in the United States are also discussed.     

Food Safety Challenges within North American Free Trade Agreement (NAFTA) Partners

Abstract: Organizational elements and limitations influencing the effective operation of the food safety regulatory infrastructures in the United States, Canada, and Mexico are compared. Progress to improve the safety of food in North American countries is hampered by common problems, yet differences exist. Foodborne illness surveillance and reporting are most comprehensive in the United States, but it is uniformly more reactive than proactive in all 3 countries. Food safety policy is based on outbreak data, but that may be short‐sighted because these represent roughly 10% of foodborne illness cases. Food inspection in each country is done at 2 tiers (federal and other) by many agencies at 3 (federal/state‐provincial/municipal) levels. Interagency collaboration at times of crisis is weak and frequent heterogeneity in training, inspection targets, and inspection rigor affect regulatory credibility. Enhanced recognition that industry has the prime responsibility for food safety is warranted (and must not be confused with self‐inspection) along with justifiably aggressive regulatory agency interrogation of food safety system performance. End product testing should be used to verify safety system operation and should not be used to predict product safety. Specific microbial and nonmicrobial challenges to safe food in North America are highlighted and a rationalization of fiscal/human resource allocation to most effectively reduce the burden of foodborne illness is provided.     

Surveillance of potentially hazardous chemicals in food in the United Kingdom.

Surveillance of chemical contaminants in food plays an important role in helping to ensure a safe food supply in those countries that undertake it. This paper reviews the methods used in the UK as a means of highlighting the essential elements required by any food chemical surveillance programme. The following topics have been covered: quantifying food consumption, setting priorities in food surveillance, developing a common approach to the surveillance of different chemicals in the food supply (including the use of Total and Duplicate Diet Studies), estimating human intakes of chemicals from the diet, developing suitably sensitive and reliable methods of analysis, obtaining representative samples, and assessing and managing risk.     

Chance,risk, uncertainty and food

It is argued that since risk contains an element of human perception about the desirability of outcomes, it cannot be predicted by scientific methods. The term chance is used to distinguish between risk and the calculable outcomes of events. It is argued that for many technological innovations the possible outcomes are not calculable because there is an insufficient knowledge base. In this case, the uncertainty of predictions must be explicitly acknowledged. In the particular case of food, it must be recognised that technology touches lives in a directly personal way. Attitudes to food technology will not, therefore, be formed on the basis of technical assessments and many other factors will need to be taken in to account when acceptable risk is assessed.     

Dissemination of central nervous system tissue from the brain and spinal cord of cattle after captive bolt stunning and carcass splitting

In the absence of reliable live animal tests for the presence of BSE in cattle, a number of measures have been applied to exclude specified risk materials (SRM) from the human food chain. However, concerns remain that current practices in the stunning and slaughter of cattle may disseminate central nervous system (CNS) tissue to meat and meat contact surfaces. The objective of this study was to establish the particular risks of CNS tissue dissemination associated with captive bolt stunning and carcass splitting. The study applied enzyme linked immunosorbent assays (ELISAs) in the detection and quantification of two CNS proteins, syntaxin 1b and GFAP. The study observed extensive dispersal of both CNS proteins onto equipment, beef hide and personnel. These results demonstrate that despite the rigorous application of current SRM control policies, normal slaughter practices continue to present significant opportunities for CNS material including BSE prion present in the CNS of any sub-clinically infected cattle to contaminate meat entering the human food chain.     

Autonomous nervous system with respect to dressing of cattle carcasses and its probable role in transfer of PrP(res) molecules

Pathogen prions are widely recognized as the causative agent in bovine spongiform encephalopathy (BSE) and other transmissible spongiform encephalopathies. However, more research on the possible transmission mutes of this agent once it has reached the host is needed. There is evidence based on the anatomy and physiology of the autonomous nervous system (ANS), as well as observations for different animal species, that the ANS might be involved in the axonal drainage of pathogen prions toward the central nervous system. In this context, more attention should be paid to the cranial cervical ganglion, the stellate ganglion, the chain of paravertebral ganglia next to the first six thoracic vertebrae, the chain of the paravertebral ganglia next to loin vertebrae 1 through 6, the vagus nerve in the neck region and in the mediastine, and the esophagus (because of its close connection to the vagus nerve). For a more detailed risk analysis with respect to these tissues, the ANSs of animals having shown clinical signs of BSE might be examined to corroborate the evidence presented here. In the meantime, as a precautionary measure, the tissue addressed should be taken out of the human food chain, taken out of animal feed, and handled as if it were specified risk material. It is technically possible to remove these parts during cutting and dressing.     

Managing risks from pests in global commodity networks – policy perspectives

Up to 80 % of global commodity production comes from smallholdings of less than 0.5 ha. Yet commodity crops may be a substantial proportion of a country’s exports, and feed into global supply networks. Pest risks thus have consequences at local, national and global levels. We consider three categories of risk in global commodity networks: introduction of pests to new areas, upsurges of established pests and the risks arising from management efforts. In each category we provide case studies and examples, and consider policy options. Increased travel, trade and transport increase the risks of introduction. Commodity specific biosecurity plans are required for preventing introductions, including analysis of the specific risks (pest pathways) and preparation of emergency responses. Regional and international cooperation is essential. Upsurges can be caused by crop management, evolution of new strains, and environment change. National systems must be responsive to detect problems and address them quickly. Capacity building for surveillance and diagnostics, and the development and dissemination of integrated pest management methods are needed. Investment in research and extension for the agricultural sector is vital. Risks linked with management efforts, specifically, the risk from agrochemicals are considered. Concerns in developed countries over food safety and environmental damage can place constraints on pest management. Failure to comply leads to loss of markets and buyer confidence. Policies that favour lower-risk pest management methods are needed, but are often lacking.