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.     

猪繁殖与呼吸综合征引起的疾病风险评估

起始于2003年的开发工作已经完成了一个PRRS风险评估系统,利用该系统能够对会影响PRRS病毒被清除后的猪群是否能够保持PRRS阴性的风险因素进行评估.     

The potential risk of infectious disease dissemination via artificial insemination in swine

Artificial insemination (AI) is one of the most widely used assisted reproductive technologies in swine. To maintain a healthy semen trade, it is crucial that diligence be given to managing and minimizing the chance of extended semen playing an epidemiological role in the transmission of infectious disease. In swine, pathogens of primary importance, which may be transmitted through semen include Aujeszky's disease, brucellosis, chlamydophilosis, porcine circovirus type 2, classical swine fever, Japanese encephalitis, leptospirosis, parvovirus, porcine reproductive and respiratory syndrome, rubulavirus, foot-and-mouth disease and swine vesicular disease. This paper will summarise the current state of knowledge pertaining to these pathogens in relation to swine AI.     

Probabilistic models for food-borne disease risk assessment

Risk assessment is a tool used by manufacturers, governmental, or regulatory bodies to evaluate the safety of food production systems and decide on strategies to protect consumers. This article presents a general approach to the use of probabilistic models to assess the risk related to specific hazards in some categories of food. It discusses their value in organising and analysing the scientific knowledge about the factors that most affect risk along the food production chain, but also highlights the data gaps that currently hamper accurate risk assessment.     

疯牛病和口蹄疫之比较

疯牛病和口蹄疫是牛、羊、猪等家畜类动物的灾难性疾病，具有发病快、传播广、死亡率高和灾害重的特点，如果处置不力、常常会对一个国家乃至全世界的畜牧业带来毁灭性的打击，与此同时，还会对人类的身体健康造成很大的危害。     

Estimating the impact on the food chain of changing bovine spongiform encephalopathy (BSE) control measures: The BSE Control Model

The decline in the bovine spongiform encephalopathy (BSE) epidemic in Great Britain (GB) demands a review of control strategies to ensure that they remain proportionate. Amongst controls that are subject to review are those intended to minimise the risk of BSE exposure of consumers through food. Such risk mitigation steps are costly, and the relative impact of each in terms of human exposure to BSE infectivity is not known. This risk assessment, termed the BSE Control Model, aims to estimate by use of stochastic simulation the impact of testing of cattle at slaughter and the removal of Specified Risk Materials (SRM) on potential BSE infectivity consumed. This paper describes the use of the model to investigate the effect of different risk management methods that have been or could be implemented between 2005 and 2010.Our results suggest that the amount of infectivity consumed in 2005 with the Over Thirty Month (OTM) rule in place was a mean of 0.03 bovine oral ID₅₀ (BO ID₅₀). This is an extremely low amount, particularly considering that it would be spread over, on average, 236 infected carcases that would be further sub-divided into portions for human consumption. The highest contributor to the total amount of infectivity consumed per year is spinal contamination at carcase splitting (35%). In 2006 the OTM scheme was discontinued and head meat was again permitted into the food chain. These changes resulted in an increase in the amount of infectivity consumed, rising to an estimated 28 BO ID₅₀ in 2006, and 19 BO ID₅₀ in 2007.In 2008 the age at removal of vertebral column was raised from 24 to 30 months, and an estimated 24 BO ID₅₀ of infectivity was consumed. At the beginning of 2009 the age at testing of cattle was raised to 48 months for healthy slaughter, emergency slaughter and fallen stock. Under these conditions, an estimated mean of 24 BO ID₅₀ will be consumed in 2009, decreasing to 20 BO ID₅₀ in 2010. Even though presented in terms of bovine rather than human oral ID₅₀, such estimates represent an extremely low exposure of the British population. Considerable uncertainty would surround any attempt to try to convert such exposure into estimates of new cases of vCJD, but the most recent estimates of the size of the species barrier between cattle and humans (4000, EFSA, 2006) suggest that there would be few, if any, new cases of vCJD arising from such exposure levels.     

Epidemiologic aspects of scrapie and BSE including an analysis of risk factors

After a discussion of the different hypotheses about the causative agent of prion diseases, various aspects of the two most important animal prion diseases, i.e. BSE and scrapie are described. This thesis focuses on the search for a preclinical diagnosis. A major breakthrough was the discovery of a new technique for detecting the disease-associated protein in tonsillar biopsies from scrapie-infected sheep long before clinical signs appeared. Another essential part of the studies described in this thesis concerned a risk analysis for BSE in a country like the Netherlands. Major risk factors were assessed, including an assessment of the efficacy of Dutch rendering procedures in the inactivation of the agents of scrapie and BSE.     

饲用草产品主要真菌毒素污染检测、风险评估与控制研究进展

饲用草产品在收获、加工、贮藏及运输过程中易遭受雨淋、干燥不完全或装卸挤压时造成叶片脱落发生真菌性病害,引起品质劣变,不仅直接带来经济损失,而且部分真菌毒素会对家畜及人类健康造成安全隐患.真菌毒素是继农药残留、病虫害、无机污染物后,影响饲用草产品质量安全的关键风险因子.饲用草产品中真菌毒素的污染状况、检测方法、限量标准和...     

Risk assessment and surveillance for bovine spongiform encephalopathy (BSE) in Argentina

An assessment was made of the risks of bovine spongiform encephalopathy (BSE) occurring in Argentina. Most of the factors associated with the origin and development of the BSE epidemic in the UK are essentially absent. For example, Argentina's large sheep and cattle industries are based on low-cost production systems using grass. Concentrated feeds are not used for sheep, rarely for beef cattle and to a comparatively modest extent for dairy cows. Particularly important are the facts that scrapie (and BSE) has never been reported in Argentina—very small amounts of waste tissues from sheep are rendered to produce meat and bone meal (MBM)—and MBM is not used in concentrated feeds for cattle. We conclude that Argentina has an exceptionally low risk of BSE due to scrapie. There is a very small risk of BSE having been introduced via live animals imported from countries with BSE, but this could only give rise to isolated cases because MBM is not fed to cattle.

A surveillance programme has been carried out based largely on a histological examination of brains from three categories of old dairy cows: animals reported on the suspicion of having neurological disease; animals in poor condition at slaughter; healthy animals randomly selected in the abattoir. No evidence of transmissible spongiform encephalopathy was seen in several sections from each of a total of 1019 brains. We conclude that, for most practical purposes, Argentina may be considered to be free from BSE.     

Clinicopathological presentation of cardiac disease in cattle and its impact on decision making

The records of 116 cattle suffering from cardiac disease were examined retrospectively. On the basis of the results of postmortem examinations there were 52 cases of endocarditis, 39 of pericarditis and 25 congenital cardiac defects. The most useful clinical tool for differentiating between these conditions was auscultation of the heart. The cases of pericarditis were characterised by muffled heart sounds, and the cases of endocarditis and congenital cardiac defects were characterised by a cardiac murmur. Endocarditis could be differentiated from congenital cardiac defects by the presence of a jugular pulse, venous distension, oedema, a reduced appetite, pain and polyarthritis, whereas congenital defects were associated with conformational abnormalities. These two conditions could also be differentiated by differences in the plasma sodium concentration, the albumin:globulin ratio, red blood cell count, lymphocyte count and haematocrit. The ability to differentiate between these three groups of cardiac diseases can help the veterinary practitioner in deciding whether treatment, economic salvage (slaughter for human consumption) or disposal (slaughter not for human consumption) is likely to be the best option.     

Sensitivity and specificity of a commercial BSE kit for the detection of ovine scrapie

To examine the sensitivity of a commercially available bovine spongiform encephalopathy (BSE) kit (NippIBL) for the detection of ovine scrapie, 50 scrapie‐positive ovine samples from the UK, and 54 scrapie‐negative ovine samples from Japan were obtain and tested using this kit. The sensitivity and specificity of NippIBL for ovine samples were 96% and 100%, respectively. The detection limit of the abnormal isoform of prion protein (PrP^Sc) of NippIBL was examined using diluted scrapie‐positive samples. The sensitivity of NippIBL to ovine scrapie was 3–10 times superior to that of another commercial BSE diagnosis kit. Thus, the NippIBL kit proved more effective for the detection of ovine scrapie.     

Case-control study on feed risk factors for BSE cases born after the feed ban in France

In France, after the ban on meat and bone meal (MBM) in cattle feeding in June 1990, cases of Bovine Spongiform Encephalopathy (BSE) have continued to be detected in bovines born after that ban (called BAB cases). A case-control study was therefore carried out to determine the way these cases were contaminated. A multivariate conditional model was built adjusting for the production type of the animals and taking into account the herd size. The results confirmed that feeding cattle with proprietary concentrates was at risk for BSE, with an adjusted odds ratio of 6.8 (2.5; 18.7) for the consumption of less or three different proprietary concentrates and 17.6 (5.7; 54.8) for more than three, when comparing with no consumption of proprietary concentrates, considering feeding of bovines before the age of two. The results suggest that cross-contaminations by MBM in bovine concentrates have occurred after 1990. To a lesser extent, on-farm cross-contaminations, i.e. consumption by cattle of feedstuffs initially dedicated to other animals and which could legally contain MBM, have probably also existed, since the presence on farms of poultry fed purchased feed involved an increased risk of BSE with an odds ratio of 1.8 (1.1; 3.0). The use of milk replacers, which often incorporates animal fats, was also at risk with an odds ratio of 1.8 (1.0; 3.1).     

Predictive microbiology and risk assessment

Predictive microbiology (predictive modelling PM), in spite of its limits and short-comings, may often contribute to a reduction of the problems arising when HACCP systems are established or microbiological risk assessment is done. Having identified the agents which constitute a risk and the contamination rate and density in the raw material, the influences of production steps and storage on these microorganisms have to be examined. Finally, there should be an exposure assessment, i.e. an estimate of the contamination density in the final product at the time of consumption. Should the exposure assessment together with data from dose response assessments reveal a potential for intake of inacceptable numbers of organisms, the risk identified has to be characterized. As a consequence, risk management should result in a modification of the composition of the product and/or of the production process so that the risk does not surpass an acceptable limit. For this approach it is indispensable to have product- and process-specific information on the multiplication of pathogens prior to heat treatment, on reduction of their density by thermal treatment and on growth or dying of organisms having survived heat treatment or penetrated into the product after heat treatment as post-process contaminant. Commonly, challenge tests are conducted to provide such information. But they are time consuming and, as their results are only valid for the specific product tested and the conditions prevailing during the experiment, the have to be repeated if there is any modification of intrinsic or extrinsic factors. At least partially, the PM may replace the challenge tests. The efficiency of the models is rated particularly high if they are used already at the stage of product development when the question has to be answered whether a planned recipe or process of production are already save or have to be modified to become save.     

A quantitative assessment of the BSE risk associated with fly ash and slag from the incineration of meat-and-bone meal in a gas-fired power plant in Denmark

It has been recommended that meat-and-bone meal (MBM) be incinerated at 850 °C for at least 2 s and the ashes and slag disposed of in controlled landfills, to dispose of animal-derived proteins. Most commonly, the MBM is incinerated in cement works or coal-fired power plants and the ashes and slag are incorporated into the cement or concrete.

Our goal was to assess with a Monte Carlo simulation model the bovine spongiform encephalopathy (BSE) risk to cattle and humans posed by the ash and slag. The results will be used by decision makers to evaluate the need for disposal of the fly ash in controlled landfills and the feasibility of use of the ash by the phosphate and fertilizer industries.

We assumed that all specified risk material (SRM) and MBM produced in Denmark would be incinerated in this gas-fired power plant. Based on observations in 2001, we assumed that, on average, six (range: 0–15) clinical BSE cases each year were rendered into MBM and incinerated. In addition, SRM or carcasses from 0 to 31 (median = 10) BSE-infected-but-undetected animals/BSE case were also incinerated.

The simulations were run on a 1-week basis. Our results suggest that if the slag is collected and re-incinerated the median BSE infectivity remaining in the fly ash per week would be 3.1E−11 cattle ID₅₀. A cattle ID₅₀ is the amount of infectivity that will cause infection in 50% of cattle exposed to it. During the weeks when BSE was infected in the SRM-MBM, the median infectivity in the fly ash was estimated as 8.7E−10 cattle ID₅₀ and 2.9E−12 human ID₅₀. The 95th percentiles were 2.1E−08 cattle ID₅₀ and 5.8E−10 human ID₅₀, respectively. One ton of fly ash would contain ≤1.8E−07 cattle ID₅₀ 95% of the time. These are the potential exposures of the cattle or human populations. The potential exposures of individuals are far less.     

The foot–surface interaction and its impact on musculoskeletal adaptation and injury risk in the horse

The equine limb has evolved for efficient locomotion and high‐speed performance, with adaptations of bone, tendon and muscle. However, the system lacks the ability seen in some species to dynamically adapt to different circumstances. The mechanical interaction of the limb and the ground is influenced by internal and external factors including fore–hind mass distribution, lead limb, moving on a curve, shoeing and surface properties. It is unclear which of the components of limb loading have the largest effect on injury and performance but peak load, impact and vibration all play a role. Factors related to the foot–ground interface that limit performance are poorly understood. Peak performance varies vastly between disciplines but at high speeds such as racing and polo, force and grip are key limits to performance.     

Effects of BSE on consumer attitudes and behavior

The extremely high media emphasis of the BSE issue during the period December 2000 to February 2001 has caused considerable short term public concern. A significant amount of this concern was due to an intensive communication of pictures. Pictures are "fast shots into the brain" (Kroeber-Riel). Pictured stimuli run under the cognitive control of the recipients effecting the consumer below the threshold of consciousness. However, the issue has fallen into oblivion very soon. In summer 2001 the public concern was not higher than before the BSE crisis. The perception of product quality regained a "normal level". The public concern has caused a considerable decline of the demand for beef and an increase of demand for substitutes and organic meat. When the media emphasis of the BSE issue diminished, the beef demand recovered but did not reach the pre-crisis level again. However, the BSE crisis has intensified animal welfare concerns, polarized public opinion about food and agriculture and had big effects in the political sphere. Furthermore, the BSE crisis has led to additional--politically supported--activities of the organic food suppliers causing a further growth of this market segment.     

Animal feeding and feed legislation after the detection of the first indigenous BSE cases in Germany

In Great Britain, even the earliest tangible signs indicating the epidemiologic significance of meat and bone meal in the spreading of BSE soon gave rise to increasingly rigorous legislative measures regulating animal feedstuffs. In 1994 a ban on the feeding of animal proteins to ruminants was implemented throughout the entire EU. But until the first BSE cases were actually confirmed in locally raised cattle (November 2000), feeding practice and legislation more or less in Germany remained unaffected by the efforts undertaken in Great Britain. This situation was suddenly changed on 1 December, 2000, when the so-called "Verfütterungsverbot" was put into effect, a law which drastically extended bans regarding the feedstuffs (including fishmeal and animal fats) as well as the species concerned (all animals used in food production). In 2001 the "contamination" phenomenon (ingredients of animal origin were detected in mixed feeds) became a vital issue for the feed industry; through the media, the subject "feedstuff safety" gained a previously unseen level of public awareness. Those circles concerned with mixed feed production and animal husbandry were increasingly confronted with the consequences of the "Verfütterungsverbot" (availability and pricing of substitute ingredients; the demand for amino acids and inorganic sources of phosphorus; problems finding adequate substitutes for animal fats; poor digestibility of alternative components such as indigenous legumes or vegetable fats in calf diets; lower utilization rate of original phosphorus in mixed feeds with negative consequences for skeletal development). With the conditional approval of fishmeal (except in feeds for ruminants) the situation has eased again to a certain degree; on the EU level there are increasing signals pointing toward a political intention to reinstate the utilization of by-products of slaughtered animals qualified for human consumption (with the exception of fallen/dead animals and specific risk material) in poultry and swine feeding. In Germany, at least, the question of animal fat utilization for food-producing animals is still unsolved.     

Poultry, pig and the risk of BSE following the feed ban in France--a spatial analysis

A spatial analysis was carried out in order to analyse the reason why the risk of Bovine Spongiform Encephalopathy (BSE) was spatially heterogeneous in France, during the period following the feed ban of Meat and Bone Meal to cattle. The hypothesis of cross-contamination between cattle feedstuff and monogastric feedstuff, which was strongly suggested from previous investigations, was assessed, with the assumption that the higher the pig or poultry density is in a given area, the higher the risk of cross-contamination and cattle infection might be. The data concerned the 467 BSE cases born in France after the ban of meat and bone meal (July 1990) and detected between July 1st, 2001 and December 31, 2003, when the surveillance system was optimal and not spatially biased. The disease mapping models were elaborated with the Bayesian graphical modelling methods and based on a Poisson distribution with spatial smoothing (hierarchical approach) and covariates. The parameters were estimated by a Markov Chain Monte Carlo simulation method. The main result was that the poultry density did not significantly influence the risk of BSE whereas the pig density was significantly associated with an increase in the risk of 2.4% per 10 000 pigs. The areas with a significant pig effect were located in regions with a high pig density as well as a high ratio of pigs to cattle. Despite the absence of a global effect of poultry density on the BSE risk, some areas had a significant poultry effect and the risk was better explained in some others when considering both pig and poultry densities. These findings were in agreement with the hypothesis of cross-contamination, which could take place at the feedstuff factory, during the shipment of food or on the farm. Further studies are needed to more precisely explore how the cross-contamination happened.