广东省广州市猪禽屠宰场环境沙门氏菌血清分型与耐药性分析

为了解广东省广州市屠宰环节环境中沙门氏菌血清型分布及其耐药性,对广州市大型生猪、家禽屠宰企业环境进行监控,对比分析猪禽屠宰场污染的沙门氏菌主要血清型和耐药谱.采集屠宰场的空气、土壤、污泥样品,以及运输车辆、待宰圈/舍、屠宰车间等环境拭子样品,利用沙门氏菌特异性引物进行PCR扩增和测序鉴定;通过玻片凝集法,对PCR鉴定阳...     

Simulation-based estimation of BSE infection in Japan

The first case of bovine spongiform encephalopathy (BSE) in Japan was found in September 2001. As a result, national BSE surveillance systems in slaughterhouses and farms were introduced between October 2001 and April 2004. All cattle, with the exception of those under 24 months of age that die at farms, now undergo compulsory testing when they die or are slaughtered. The removal of specified risk material (SRM) from all slaughtered cattle and a ban on the feeding of meat-and-bone meal to all farm animals were implemented in October 2001. However, infected cattle that died or were slaughtered before these measures were put into practice could have been a source of infection to other cattle through the rendering process. The slaughtered cattle could also have been a source of infection to humans via SRM that entered the food chain. The purpose of this study was to estimate the number of BSE-infected cattle that could have been a source of infection to cattle and humans before October 2001. Since all typical cases were dairy cattle, this study focused on the dairy cattle population. We developed a simulation model to obtain the year of death and the final disposition of infected cows born in each year from 1996 to 2001. In this model, the dairy cattle population was divided into birth cohorts, and parameters regarding its population dynamics were assumed to be constant. Using this model, the total number of infected cattle in each birth year was estimated by maximum likelihood estimation using data on the number of detected cases from 2002 to 2006. Finally, the number of infected cattle that died or were slaughtered each year was estimated by Monte-Carlo simulation using the same model with the total number of infected cattle estimated by maximum likelihood estimation. It was estimated that the majority of infected cattle that could have been sources of infection before 2001 were born in 1996. The total number born in 1996 was estimated to be 155 (95% confidence interval: 90-275). Of these 155 cattle, 56 died or were slaughtered before October 2001, after the accumulation of infectious agent in their bodies. Only 5 of these 56 cattle were estimated to have been slaughtered. Therefore, the number of infected cattle that could have served as a source of human infection would appear to have been a very limited subset of the BSE-infected cattle in Japan.     

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.     

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.     

Spatial heterogeneity of the risk of BSE in France following the ban of meat and bone meal in cattle feed

In France, meat-and-bone meal (MBM) has been prohibited for cattle feeding since 1990, but bovine spongiform encephalopathy (BSE) cases, called 'NAIF', appeared in animals born after this feed ban. Furthermore, in 1996 a new measure was taken: removal of cadavers and specified risk materials (SRM) from the processing of MBM dedicated to animal feed. Nevertheless, BSE cases (called 'super-NAIF') appeared in cattle born after this measure was in force. We analysed the spatial distribution of 445 'NAIF' and 58 'super-NAIF' cases detected in France from July 1, 2001 to July 31, 2003. The detection of BSE was based both on the mandatory reporting system (MRS) and the systematic test screening of cattle at the abattoir and at the fallen-animal plant with rapid tests. The background population was based on the adult-cow census. The disease mapping of the BSE risk was based on the standardised incidence ratio (stochastic Poisson process). A spatial component, which takes into account the spatial dependence between the geographical units by a notion of adjacency was used to eliminate the over-dispersion in the risk assessment. The geographical units were defined by hexagons with a side of 23km (France had 1264 hexagons). The parameters were estimated by a Metropolis Gibbs sampling algorithm using the Markov-chain Monte Carlo methods. The BSE cases were not randomly distributed. Furthermore, the areas at risk for the 'super-NAIF' matched part of the areas at risk for the 'NAIF' cases-which suggests that it might be a common source of contamination.     

冻(冰鲜)牛肉贸易风险预警特征及出口安全控制

为揭示全球主要贸易国家/地区冷冻(冰鲜)牛肉的进出口风险特征,确定牛肉生产链(肉牛养殖—屠宰加工—出口)全过程安全风险关键控制环节,对2012年9月—2020年11月全球主要贸易国家(地区)210例/217种次冻(冰鲜)牛肉安全风险预警案例进行统计分析,同时采集重庆市出口牛肉加工备案企业的牛肉样品以及备案牛场的肉牛、饮...     

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.     

Meat and potential risks

By the term "meat" the consumer understands muscle meat, that is skeletal muscle. The german regulations, the "Leits?tze für Fleisch und Fleischerzeugnisse" as well as the Codex Alimentarius define meat in a much broader sense to include all edible parts of slaughtered or shot warm-blooded animals (skeletal muscles, fat, heart, gut, liver etc). Therefore, a differentiated procedure is required when the risk of BSE transmission by meat has to be estimated. This must be based on knowledge of occurrence, amount, and persistence of BSE agents in the organs of animals. The risk evaluation has to include further factors: differences between animal species, age of the animal at the time of slaughter, the possibility of contamination during the slaughtering and cutting process, and--as far as meat products are concerned--the processing technology. To date there are no indications for the existence of transmissible spongiform encephalopathy in pigs, poultry and fish, even though BSE has been transmitted to pigs experimentally by intracranial administration. Muscle meat of these species can be considered safe. Muscle meat of experimentally infected cattle in the preclinical stage and even of animals with clinically manifest BSE has not shown infectivity in homologous and autologous bioassays performed so far. This finding justifies the assumption that the risk of BSE exposure by the consumption of beef can be classified as extremely low. Nevertheless, the absence of a proof of infectivity can at present not be equated with absence of BSE agents. This is because of the limits of sensitivity of the bioassays and because muscle meat does contain non-muscle tissue such as connective tissue collagen, nerve and lymph tissue and blood vessels.     

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.     

BSE situation and establishment of Food Safety Commission in Japan

Eight major policies were implemented by Japanese Government since Oct. 2001, to deal with bovine spongiform encephalopathy (BSE). These are; 1) Surveillance in farm by veterinarian, 2) Prion test at healthy 1.3mi cows/yr, by veterinarian, 3) Elimination of specified risk material (SRM), 4) Ban of MBM for production, sale use, 5) Prion test for fallen stocks, 6) Transparent information and traceability, 7) New Measures such as Food Safety Basic Law, and 8) Establish of Food Safety Commission in the Cabinet Office. At this moment, the extent of SRM risk has only been indicated by several reports employing tests with a limited sensitivity. There is still a possibility that the items in the SRM list will increase in the future, and this indiscriminately applies to Japanese cattle as well. Although current practices of SRM elimination partially guarantee total food safety, additional latent problems and imminent issues remain as potential headaches to be addressed. If the index of SRM elimination cannot guarantee reliable food safety, we have but to resort to total elimination of tissues from high risk-bearing and BSE-infected animals. However, current BSE tests have their limitations and can not yet completely detect high-risk and/or infected animals. Under such circumstances, tissues/wastes and remains of diseased, affected fallen stocks and cohort animals have to be eliminated to prevent BSE invading the human food chain systems. The failure to detect any cohort should never be allowed to occur, and with regular and persistent updating of available stringent records, we are at least adopting the correct and useful approach as a reawakening strategy to securing food safety. In this perspective, traceability based on a National Identification System is required.     

A case-control study of risk factors in light Taenia saginata cysticercosis in Danish cattle.

Risk factors in light T. saginata cysticercosis in cattle herds were investigated in a case-control study. The case group consisted of farms from which cattle with low-grade cysticercosis had been detected at slaughter. The control group consisted of farms where no cases were detected during the same period. The major risk factor identified was allowing cattle access to drink from streams carrying effluent from sewage treatment plants (odds ratio = 3.6). Spreading of septic tank sludge through deliberate or accidental mixing with animal slurry, deposition of sewage sludge, and proximity to railways, camping sites or sewage treatment plants seemed to be of minor importance.     

Clinical examination of cattle for BSE in a cattle facility and slaughterhouse

Detection of a case of BSE in slaughtered cattle causes considerable expenses. It seems therefore desirable to screen cattle before slaughtering and exclude suspect animals from slaughter. The object of this study was to determine the practicability of such screening under realistic conditions in a large slaughterhouse and to evaluate the specificity of the tests proposed by BRAUN et al. (1997). 949 cattle over 24 months old were examined in the Munich slaughterhouse. Spontaneous behaviour and the reaction to tactile, acoustic, and optical stimuli only could be tested. The evaluation of locomotion was not possible without interference with the routine processing of cattle before slaughter. The examination took about three minutes per animal. The results were evaluated using a modification of the scheme of BRAUN et al. (1997). The specificity of the classification "BSE very likely" was 97.8%. If all animals that exhibit any signs suggestive of BSE were to be excluded, the specificity would drop to 63.7%. This pre-slaughter clinical screening is not useful.     

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.     

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.     

Halal slaughtering,welfare, and empathy in farm animals: a review

Pre-slaughter and slaughter stressors are considered major concerns in animal welfare. Halal slaughtering method is considered one of the slaughtering stressors in livestock. This method seems to cause fear followed by stress in animals mainly due to inhuman handling. In this review, empathy and animal welfare are discussed in light of Islamic sharia and has further linked with animal’s physiology and behavioral responses during slaughtering. Islam as a religion forbids slaughtering an animal in front of another animal as through optic, olfactory, and cochlear senses animals can perceive the stress state of conspecifics. This suggests and strengthens the hypothesis that animals being slaughtered in front of each other may produce stress in them. This argument further leads to a claim that animals can experience empathy of each other through olfaction of semiochemicals (stress pheromones) emitted from animals slaughtered in the stressful condition that can be detected by other animals in abattoirs. Hence, research is needed to find out these specific stress pheromones and legislation needs to be adopted in slaughterhouses to isolate the areas of butchery from slaughtering lines to ensure proper guidelines of Halal slaughtering in slaughterhouses.     

Risk factors associated with Salmonella enterica subsp. enterica contamination of chicken carcases in Senegal

The objective of this study was to identify the risk factors for Salmonella spp. contamination of Senegalese chicken carcases during slaughtering. One hundred and twenty traditional slaughterhouses were studied from January 2000 to December 2002 in and around Dakar. A questionnaire was administered to the slaughterers and samples of breast skin were taken to assess the Salmonella spp. status of chicken carcases. Results showed that 43.3% of the chicken batches were contaminated with Salmonella spp., with Salmonella Hadar and Salmonella Brancaster as the two main serovars. Salmonella spp. contamination of the live birds before slaughtering was related to contamination of the carcases after slaughtering. Feed withdrawal before slaughtering and thorough cleaning and disinfection procedures decreased the risk of Salmonella contamination. One individual worker for each slaughtering stage was also associated with a decreased risk of Salmonella contamination. Using scalding water for plucking increased the risk of contamination. These results will help slaughterers to produce safer products for local consumers.     

BSE--consequences for slaughtering,cutting and employer's protection

The conventional slaughtering of cattle includes some critical process stages where a carry over of BSE-risk material (brain, spinal cord) on the meat can occur. These processes are captive bolt stunning, cut off the head and first of all sawing the spine lengthways. Alternative stunning methods like electrical stunning or concussion stunning are under investigation, nevertheless they are in the moment no useful alternatives for most of the slaughter houses. The most promising methods available at present for minimising the risk appear to be in manual cattle slaughtering boning the entire carcass, either still warm or refrigerated and in industrial beef cattle slaughtering extraction of the spinal cord by vacuum from the whole carcass followed by conventional sawing or completely sawing out the spine including spinal ganglia. Working processes, including the cutting or exposure of risk material, are a risk for the employer's too. Special protective measures must be taken.     

The use of urban sewage sludge on pastures: the cysticercosis threat

Urban sewage production is increasing and its agronomical use as a fertiliser has been advocated. Considerable defiance is prevalent in consumers and among farmers on the use of such fertilisers due to unknown pathological or environmental risks. The aim of the present review was to consider which pathological risk is major. Cysticercosis due to Taenia saginata appears to be one of the major pathological threats when sewage sludge is used to fertilise cattle pastures in temperate areas. The situation is different in Africa (Taenia solium and T. saginata are both highly prevalent) and Asia (Taeniasaginata-like are prevalent). The processing of sludge and the delay between its application onto a pasture and grazing are probably major risk factors. Little data are available on the influence of processing, delay between processing and the use of sludge on the pathogenic risk. Producers and consumers will be more confident on the use of sludge if objective data are gained on risk. Most of the cases of cysticercosis (North America, United-Kingdom, Germany or Denmark) are related to poor human hygiene or accidental overflooding of sewage plants onto pastures. The standard application of sludge on pastures is apparently at low risk. This low risk does not mean that surveillance should cease since outbreaks of cysticercosis have been reported. Future investigations should concentrate on the most sustainable means of reducing risk (length of storage before use, composting, other treatments).     

Very low helminth infection in sheep grazed on pastures fertilised by sewage sludge or cattle slurry

Helminth infection acquired by lambs grazing on pastures fertilised either by urban sewage sludge or cattle slurry were studied in temperate Central Western France. The aim was to assess the risk of larval cestodoses in lambs after sewage application and of digestive tract nematode infection following the slurry application. Twenty-six sheep were allocated on two paddocks of 0.7 ha, one fertilised with sludge and the other with cattle slurry. The delay between application and actual grazing was 6 weeks; grazing on these paddocks extended from mid July to beginning of November 2002. The herbage biomass was slightly increased in the sludge paddock but it did not result in an increase of lamb live weight, compared with the slurry paddock. The lambs did not acquire cysticercosis or any other larval cestodoses in the sewage sludge group and only very limited infections with Cooperia spp. and Nematodirus spp. were observed in the slurry group. It was concluded that in our conditions the helminth risk was extremely low and was not a cause of restriction of the use of these biowastes.