食品和饲料中动物源性成分的检测和分析方法概述

疯牛病(BSE)是一类引起神经系统进行性变性的疾病,由于该病与人类的变异型克雅氏症(vCJD)有关,因此曾引起世界范围内的恐慌.世界各国为控制疯牛病的发生和传播纷纷采取措施并出台了一系列禁令,包括饲料禁令和特殊风险物质(SRMs)禁令[1].     

疯牛病研究进展

疯牛病 ( mad cow disease)是牛海绵样脑病 ( bovinespongiform encephalopathy,BSE)的俗称 ,是动物传染性海绵样脑病 ( transmissible spongiform encephalopathy,TSE)中的一种 ,1 986年首先在英国发现 [1] ,然后传播到欧洲多个国家和地区 ,给英国和欧洲的养牛业造成了巨大损失 ,并影响到相关的用牛源材料的工业。特别是随着 BSE的流行 ,由同一致病因子引起的人的变异型克雅氏症( new variant Creutzfeldt-Jakob disease,nv CJD,v CJD)的出现 ,导致了全世界对疯牛病的恐慌。可以说 ,BSE已给动物和人类健康及国际贸易等领域带来全球…     

牛源大肠杆菌耐药性研究进展

牛源致病性大肠杆菌是导致牛细菌性疾病的重要病原体之一,抗菌药是治疗及预防牛大肠杆菌病的重要手段,然而在养殖过程中,长期且不合理的使用抗菌药物,导致大肠杆菌耐药问题频发,且耐药性具有通过人与动物的直接接触或借助食物链将耐药基因从动物传播给人类的可能,严重威胁人类健康及公共卫生安全。本文根据近几年国内外关于牛源大肠杆菌耐药性基因的研究报道,对大肠杆菌耐药机制、耐药基因检出率及耐药表型进行综述,以期为大肠杆菌耐药性的研究提供参考。     

WHO发布疯牛病、食品安全与生物恐怖指南

为了帮助政府、消费者协会以及其他相关组织更好地保护消费者免受感染疯牛病 (BSE)的危险 ,世界卫生组织 (WHO)于2 0 0 3年 1月 30日发布了一个以“U nderstanding the BSE threat”为标题的指南 ,该指南给政府和其他涉及到消费者保护的组织提供了疯牛病的背景知识以及如何防止其传播的措施。疯牛病是由侵染性蛋白因子 (Prion)引起的一种新的疾病 ,首例牛的疯牛病报道于 1986年 ,1996年与牛的疯牛病流行相关的人变异型克雅氏症 (v CJD)出现 ,当前对这 2种病的许多科学问题还没有绝对确证的答案 ,但是人们对疯牛病流行的起源、传播的原…     

辽宁从美国进口鸡骨粉中检出牛源成份

今年以来,辽宁检验检疫局利用“饲料中动物源性成份分子生物学检测技术”加大检测力度,严把疫情关,连续两次从美国进口的鸡骨粉中和饲料添加剂中检出牛源性成份,为口岸一线严防疯牛病疫情传入提供了技术支持。今年2月初,辽宁局保税区办事处将大连出口加工区某日资企业从美国进口21吨鸡骨粉中检出牛源性成份,21吨鸡骨粉当即被封存。这是我国首次从进口鸡骨粉中检出牛源性成份。非牛源性饲料中带有牛源性成份,要么是人为掺入,要么是加工环节受到污染。不论是哪种原因造成的,都客观地存在着传播疫情的隐患。因此,在动物疫情频发的国际环境下,加…     

牛源耐甲氧西林金黄色葡萄球菌的分子流行特征和耐药性研究进展

耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus,MRSA)是WHO公布的重要的人医临床病原菌,同时也是重要的人畜共患病原菌,对其感染的治疗是临床上难题之一。目前,世界范围内牛源MRSA呈现多重耐药现象,部分相同分子分型的MRSA克隆株已在牛和猪等不同家畜中检出,提示存在通过携带者向社区人群和医院患者传播的风险。目前的报道显示我国牛源MRSA分离株已表现出多重耐药性和分子多样性,应引起我国公共卫生领域的重视。本文综述了欧美和亚洲国家牛源MRSA耐药性和分子流行特征相关的研究成果,以期为评估我国MRSA的流行传播风险提供参考依据。     

不同来源混合加工的动物性饲料，危害到底有多大？

我国是一个蛋白饲料资源短缺的国家,利用动物副产品制成动物性饲料是补充资源不足的有效途径。但为规避风险,农业部于1992年就发文禁止在反刍动物饲料中添加或使用动物源性饲料,并于2001年再次专门发文重申这一规定。然而,目前仍有一些养殖场（户）无视国家禁令,在反刍动物饲料中添加动物性饲料产品,造成一定的“疯牛病”隐患。笔者指出,从英国开始的“疯牛病”就是由于使用了含有肉骨粉的配合饲料而引发的。特别是已证实的,即不同来源的动物性饲料对反刍动物危害最大。从安全角度看,危害来源,一是动物源性饲料特别是不同来源混合加工的动物性饲料,对动物生产确实存在着巨大的安全隐患;二是受二嗯英污染的鱼粉;三是病原生物体污染的动物性饲料;四是假劣鱼粉;五是受重金属污染动物性饲料;六是外源性毒性污染动物性饲料;七是动物性饲料来源于被疫病污染地区;八是牛羊源性动物性饲料不但禁止使用在反刍动物饲料中,而且应限制使用在宠物饲料及家禽饲料。美国为了防止疯牛病向人类传播,防止恐怖分子通过食品链发生攻击,将原来对动物脑和脊髓组织的禁用范围从牛饲料扩大到狗、猫、猪和家禽饲料。因此,动物源性饲料的安全直接关系到养殖业安全,甚至是关系到人类动物源性食品的安全。这个问题已不仅是科学利用资源的问题,更是关乎国家、国民生存安全的大问题。所以,必须引起相关饲料生产企业、养殖企业的高度重视,承担起应负的社会责任。文中提出我国于15年前就严厉禁止在反刍动物饲料中添加或使用牛羊源性动物饲料,但是在反刍动物饲料中添加或使用牛羊源性动物饲料事件却时有发生,屡禁不止。其主要原因是饲料生产企业不知饲料原料中是否含有牛羊源性动?     

海豚Prion基因的克隆与序列分析

动物海绵状脑病是一种动物中枢神经系统发生的一系列致命性神经退行性变化的疾病，包括人的新型变异型克雅氏病（v-CJD）、库鲁病（Kuru）等，动物的羊痒病（Scrapie）、牛海绵状脑病（BSE）、鹿慢性消耗性疾病（CWD）等多种疾病。 Prusiner教授提出，该类疾病的感染因子是一种不含有核酸的淀粉样蛋白颗粒，并命名为Prions（Proteinaceous infectious particles）。目前的研究表明，朊蛋白疾病的传播是由于哺乳动物食用了含有Prion蛋白感染因子的饲料而导致发病，如牛食用了含有痒病因子的肉骨粉发生疯牛病。然而，痒病致病因子只能传染给牛，不能传染给人类；但是经过中间宿主牛以后，该致病因子便可以传染给人类。对于这种现象的产生目前还不明确，有专家指出可能与Prion蛋白不同株系基因序列的变化有关。因此对动物海绵状脑病种间屏障的研究具有重要的意义。     

新疆褐牛蜘蛛腿综合征的遗传检测

蜘蛛腿综合征(Arachnomelia syndrome,AS)是一种牛的先天性致死性骨骼畸形遗传病。在瑞士褐牛群体中该病是由位于BTA5上编码亚硫酸盐氧化酶的SUOX基因外显子4上的一个G碱基的插入所致,插入突变c.363-364insG会导致SUOX蛋白编码提前终止,从而导致犊牛患病。鉴于我国新疆褐牛含有瑞士褐牛血液,本研究对我国新疆地区广泛使用的55头褐牛公牛AS致病位点c.363-364insG进行了筛查。结果显示被检的55头公牛在SUOX基因该突变位点全部为纯合子,不含G碱基插入位点,表明目前经常使用的褐牛公牛不含有致病位点,不存在传播AS疾病的风险,但未来仍需要对其他褐牛公牛及母牛群体开展检测工作,进而排除AS在中国牛群中的传播。     

结核分枝杆菌疫源追踪的基因检测分析

目的探讨牛源性人结核疫源追踪的基因分析方法。方法采用复方PCR结核杆菌快速鉴定技术,针对特征性分枝杆菌标志基因(MTP40基因、α抗原基因和IS6110),对结核病人和患牛的标本,进行检测。结果患者标本结核分枝杆菌阳性;患牛标本牛分枝杆菌和结核分枝杆菌分别阳性。结论结核病奶牛不仅是人类牛型结核的可能来源,也可能成为人类人型结核的潜在来源。     

Towards the rational use of antibiotics: results of the first International Symposium on the Risk Analysis of Antibiotic Resistance

The results of four expert working groups on the risk analysis process on anti-microbial resistance are described. They focus on the procedure recommended by the FAO/WHO CODEX Alimentarius Commission in 1999 including hazard identification, hazard characterization, exposure assessment and risk characterization. In all four areas, the current scientific knowledge was evaluated and recommendations for risk management options were given. They will form the basis for mitigating the health risk caused by resistant micro-organisms.     

Risk Assessment of Bacitracin Resistance as a Medicated Feed Additive

The aim of this study was to provide theoretical basis for regulatory departments to formulate risk management measures for bacterial resistance of animal origin.The point assessment method was applied to assess the risk of bacitracin resistance in animal origin foods of Chinese residents,according to the model of risk assessment analysis,based on the data from the monitoring report of the citizen's physiques in China in 2014,the fifth Chinese total diet study and the official website of European Medicine Agency.Dietary exposure to bacitracin was calculated by estimated daily intake,and hazard quotient (HQ) was used in risk characterisation to indicate risk level of health damage exposed to bacitracin.Firstly,through the way of hazard identification,the toxicity of bacitracin by oral ingestion was very low.But the pathogenic bacteria such as Enterococcus and Clostridium perfringens had developed resistance to bacitracin,with the resistance genes easily transferring to the human intestinal flora through bacteria commonness.Secondly,the hazard characterization indicated the toxicological ADI was 0.055 mg/(kg·BW),and the microbiological ADI was 3.9 μg/(kg·BW).Thirdly,exposure assessment showed that the maximum dietary exposure of bacitracin was in 2 to 7 age group among Chinese residents.And that of women through intake of dairy products was higher than men.Among 2 to 7 age group,dairy products contributed most to the dietary exposure of bacitracin,while meat was the largest contributor above 8 years old.Fourthly,risk characterization hazard quotient was 1.4901 for males and 1.4121 for females among Chinese residents aged 2 to 7 by calculation,and <1 among other age groups.Finally,the uncertainty analysis showed that the lack of monitoring data of bacitracin residues in animal foods,the lag of authoritative data collection and release,the absence of consumption data of aquatic products brought uncertainty to the results.In total,the risk of bacitracin resistance as a medicated feed additive through animal foods exposure was high in children aged 2 to 7 and moderate in other age groups.The maximum residue limit standard should be revised appropriately and risk management of bacitracin resistance need to be strengthened in imported animal foods.     

药物饲料添加剂杆菌肽耐药性风险评估

本研究旨在为监管部门制定动物源细菌耐药风险管理措施提供理论依据。利用2014年国民体质监测数据、第五次中国总膳食研究数据和欧洲药品管理局官方网站数据,采用抗菌药物风险评估模型,对中国居民经动物性食品摄入杆菌肽的耐药性风险进行点评估。用估算每日摄入量作为杆菌肽膳食暴露量,用危害指数（HQ）进行风险特征描述,反映杆菌肽耐药对人体健康损害的风险等级。结果表明,危害识别得杆菌肽经口毒性极低,但肠球菌、产气荚膜梭菌等致病菌已对杆菌肽产生耐药性,耐药基因可转移至人体肠道菌群。经危害特征描述可知,杆菌肽毒理学每日允许摄入量（ADI）为0.055 mg/（kg·BW）,微生物学ADI为3.9 μg/（kg·BW）。暴露评估发现,中国居民中2~7岁人群杆菌肽的膳食暴露量最高,女性通过摄入乳类的杆菌肽膳食暴露量高于男性。2~7岁人群中,杆菌肽的膳食暴露量以乳类贡献最大,8岁以上人群杆菌肽的膳食暴露量以肉类贡献最大。风险特征描述发现,中国居民中通过摄入肉、蛋、乳等动物性食品的杆菌肽耐药性风险,2~7岁人群HQ分别为男性1.4901、女性1.4121;其他年龄人群均<1。不确定性分析发现,结果不确定性源自缺乏动物性食品杆菌肽残留量监测数据、权威数据发布的滞后性、未考虑水产品等因素。综上动物性食品中药物饲料添加剂杆菌肽耐药性风险,2~7岁人群为高风险,其他年龄段人群为中等风险。针对杆菌肽的耐药性风险,必要时修订动物性食品中杆菌肽的最大残留限量,同时加强对进口动物性食品的杆菌肽耐药性风险管理。     

Biosecurity and risk management for dairy replacements.

Biosecurity, biocontainment, and disease risk management on dairy replacement operations are time- and labor-intensive, planned programs. Oftentimes the value of these programs is realized only after disease is introduced to a facility or a disease outbreak occurs. There is no "one-plan-fits-all;" each plan must be tailored to meet the needs of management's goals and expectations and problems specific to a production enterprise or geographic region. A standard framework applicable to biosecurity programs includes: (1) hazard identification, (2) exposure assessment, (3) risk characterization, and (4) risk management. The discussion presented here helps lay the framework for development and implementation of biosecurity and risk-management programs within dairy replacement facilities.     

国内外原料乳中金黄色葡萄球菌风险评估研究综述

近年来我国乳品消费量持续增加,乳品质量安全关乎着人们身体健康和生命安全.金黄色葡萄球菌及其肠毒素引起的乳品中毒事件时有发生,逐本求源地针对原料乳开展金黄色葡萄球菌风险评估研究是十分必要的.本文根据国际食品法典委员会拟定的微生物风险评估的原则和指导方针,从危害识别、危害特征描述、暴露评估、风险描述四方面综述了关于原料乳中金黄色葡萄球菌国内外风险评估的研究现状.通过国外成熟的定量风险评估案例,介绍关于原料乳中金黄色葡萄球菌定量风险评估的基本框架,提出未来应加强构建肠毒素预测模型,较为系统的对原料乳从牧场到餐桌进行全程监控和风险评估的建议.     

Prions as the driving force in transmissible spongiform encephalopathies

Transmissible spongiform encephalopathies are degenerative disorders affecting the central nervous system (CNS) occurring in a variety of species. The causative agent is thought to be composed of an abnormal form of the host encoded prion protein (PrPC), termed PrPSc. The conformational change of PrPC into PrPSc can occur spontaneously, however, it can also be induced by PrPSc. Prion diseases such as bovine spongiform encephalopathy (BSE), scrapie and variant Creutzfeldt-Jakob-Disease (vCJD) are most likely caused by peripheral uptake of prions. The process by which prions proceed to the CNS following peripheral uptake is referred to as neuroinvasion. Infection with prions is thought to occur in two phases: After ingestion prions first replicate in lymphatic tissue and then gain access to the CNS via peripheral nerves. Studies looking at the biochemical and clinical characteristics of BSE and vCJD demonstrated that BSE is most likely responsible for vCJD in humans.     

Progress and limits of TSE diagnostic tools

Following the two "mad cow" crises of 1996 and 2000, there was an urgent need for rapid and sensitive diagnostic methods to identify animals infected with the bovine spongiform encephalopathy (BSE) agent. This stimulated research in the field of prion diagnosis and led to the establishment of numerous so-called "rapid tests" which have been in use in Europe since 2001 for monitoring at-risk populations (rendering plants) and animals slaughtered for human consumption (slaughterhouse). These rapid tests have played a critical role in the management of the mad cow crisis by allowing the removal of prion infected carcasses from the human food chain, and by allowing a precise epidemiological monitoring of the BSE epizootic. They are all based on the detection of the abnormal form of the prion protein (PrP(Sc) or PrP(res)) in brain tissues and consequently are only suitable for post-mortem diagnosis. Since it is now very clear that variant Creutzfeldt-Jakob disease (vCJD) can be transmitted by blood transfusion, the development of a blood test for the diagnosis of vCJD is a top priority. Although significant progress has been made in this direction, including the development of the protein misfolding cyclic amplification (PMCA) technology, at the time this paper was written, this objective had not yet been achieved. This is the most important challenge for the years to come in this field of prion research.     

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.     

Foodborne zoonoses due to meat: a quantitative approach for a comparative risk assessment applied to pig slaughtering in Europe

Foodborne zoonoses have a major health impact in industrialised countries. New European food safety regulations were issued to apply risk analysis to the food chain. The severity of foodborne zoonoses and the exposure of humans to biological hazards transmitted by food must be assessed. For meat, inspection at the slaughterhouse is historically the main means of control to protect consumers. However, the levels of detection of biological hazards during meat inspection have not been established in quantitative terms yet. Pork is the most frequently consumed meat in Europe. The aim of this study was to provide elements for quantifying levels of risk for pork consumers and lack of detection by meat inspection. Information concerning hazard identification and characterisation was obtained by the compilation and statistical analysis of data from 440 literature references. The incidence and severity of human cases due to pork consumption in Europe were assessed in order to calculate risk scores. A ratio of non-control was calculated for each biological hazard identified as currently established in Europe, i.e. the incidence of human cases divided by the prevalence of hazards on pork. Salmonella enterica, Yersinia enterocolitica and Campylobacter spp. were characterised by high incidence rates. Listeria monocytogenes, Clostridium botulinum and Mycobacterium spp. showed the highest severity scores. The three main high risk hazards involved in foodborne infections, Y. enterocolitica, S. enterica and Campylobacter spp. are characterised by high non-control ratios and cannot be detected by macroscopic examination of carcasses. New means of hazard control are needed to complement the classical macroscopic examination.     

新型克-雅氏病是人的牛海绵状脑病

本文在概述人朊病毒的基础上，重点阐述新型克－雅氏病与早先已知的各种人朊病毒病的区别和它是由牛海绵状脑病朊病毒引起的证据，并对牛海绵状脑病并非源于痒病而是原于牛散发性朊病毒病、影响新型克－雅氏病流行规模的主要因素和该病的主要预防措施等问题进行了讨论。