食品微生物危险性评估

食品中来自微生物性危害的危险性密切关系到人类的健康。国际食品法典委员会确定的微生物危险性评估框架包括四个主要步骤：危害的确定、危害特征的描述、暴露评估和危险性特征的描述。这些步骤构成了评估食用可能污染致病菌或，和微生物毒素的食品而对人产生不良健康后果及其发生概率的系统过程。本结合这一领域的研究进展，对微生物危害危险性评估框架的各个部分及其相关因素作了综述性介绍。     

零售生鸡肉中沙门菌污染对居民健康影响的暴露评估

目的评估零售生鸡肉中沙门菌污染的健康风险及其潜在的干预措施。方法利用零售生鸡肉中沙门菌定量监测数据以及零售和家庭生鸡肉储存加工专项调查结果,采用Monte Carlo概率评估方法,估计我国居民通过厨房内交叉污染发生鸡源性沙门菌食物中毒的风险,并评价潜在的干预措施效果。结果本研究构建了从零售到餐桌的生鸡肉-沙门菌交叉污染模型,模型估计生鸡肉经过零售储存、抵达居民家里和经过家庭储存后其沙门菌浓度(lg MPN/g)从零售前的-0.017,分别增长到2.163、2.241和3.028,估计我国居民每餐发生鸡源性沙门菌食物中毒的风险为0.171(95%置信区间:0.000~0.767),其中零售阶段生鸡肉的储存方式是影响发病风险的最重要因素(回归系数=0.72),情景分析提示,如果零售阶段采用冷冻或者冷藏储存,我国居民每餐发病风险可以降为0.031(95%置信区间:0.000~0.522)。结论我国居民鸡源性沙门菌食物中毒的风险较高,应当加强零售环节生鸡肉的冷链管理。     

Food consumption data in microbiological risk assessment

The 1st International Conference on Microbiological Risk Assessment: Foodborne Hazards was held in July 2002. One of the goals of that conference was to evaluate the current status and future needs and directions of the science of microbial risk assessment. This article is based in part on a talk presented at that meeting. Here, we review the types of food consumption data available for use in microbial risk assessments and address their strengths and limitations. Consumption data available range from total population summary data derived from food production statistics to detailed information, derived from national food consumption surveys, about the types and amounts of food consumed at the individual level. Although population summary data are available for most countries, detailed data are available for a limited number of countries and may only be available in summary format. Despite the relatively large amount of detailed information collected by these national surveys, information crucial to microbial risk assessments, such as the specific types of foods, the eating patterns of susceptible populations, or an individual's propensity for consuming high-risk foods (e.g., eating undercooked hamburgers, raw shellfish, or temperature-abused foods), are not collected during these surveys.     

Comparison of microbiological risk assessment studies published

The FAO/WHO risk analysis framework and principles are in the process of being implemented in different national and international settings. The importance of a further development of international co-operation based upon agreed principles in this area is stressed in the Codex Alimentarius system, as well as under the WTO/SPS agreements. Key input in this context will come from the presentation of formalised microbiological risk assessments. The number of peer-review published microbiological risk assessments is low and the format is still variable. This paper presents a comparison of selected risk assessments in the microbiological area, and suggests a number of lessons to be learned from these.     

中国食品微生物风险评估进展与展望

食品微生物风险评估一直是国际上食品安全研究的热点。食源性致病菌引起的食品安全风险是全球性问题,发展中国家面临的情况更为严峻,我国政府高度重视食品安全工作,不断加强风险分析体系能力建设。从2010年以来,国家食品安全调查数据提示致病微生物导致的食物中毒事件的报告数一直高于化学性危害和有毒动植物造成的危害。因此加强我国微生物定量风险评估以减少与发达国家的差距,从国家层面上势在必行。     

sQMRA在微生物定量风险评估中的应用

目的以福建省人群食用牡蛎引起副溶血性弧菌(VP)胃肠炎的风险为例,介绍一种快速的风险评估工具(sQMRA)在微生物定量风险评估中的应用。方法利用《2002年中国居民营养与健康状况调查》结果、文献报告和经验推断等方式,对福建省2008年9—11月牡蛎的消费量和零售阶段VP的污染水平、交叉污染和烹制对VP菌落数的影响等共11个参数进行了推算和引用。结果计算得到福建省2008年9—11月VP的感染人数为10 221人,其中有1 022人罹患VP胃肠炎,推算得到的VP胃肠炎的发病概率为2.8×10-5,与人群监测推算的VP胃肠炎发病概率3.8×10-5结果较为接近。结论 sQMRA是一种快速简便有效的微生物定量风险评估工具。     

我国食品微生物风险评估的进展和挑战

近10余年来,我国依照《食品安全法》开展包括微生物风险评估在内的食品安全风险评估体系建设,微生物风险评估工作体系和技术体系等方面取得明显进展,成为我国开展食源性致病微生物风险评估的重要基础。随着全球后疫情时代食品供应链的变化和新技术的快速发展以及我国食品安全治理现代化需求的增加,构建基于我国膳食消费行为的评估模型、提高风险评估实施能力和质量以及实现现代技术在风险评估中的应用,将成为我国食品微生物风险评估建设的主要挑战和发展方向。     

剂量反应分析在食品微生物风险评估中的应用

微生物风险评估(Microbiological risk assessment, MRA)是食品安全管理的重要工具之一,一直是国际食品安全研究的热点。微生物剂量-反应分析是进行食品微生物风险评估中的重要工具,描述了特定人群中特定病原体(或其毒素)暴露引起特定反应的概率。本文综述了食品微生物风险评估中剂量-反应分析的研究现状,阐述了剂量反应分析研究中存在的问题,并对其进一步需开展的工作进行了展望,以期为我国食品微生物风险评估和食品安全监管提供参考。     

Quantitative risk assessment of Campylobacter spp. in poultry based meat preparations as one of the factors to support the development of risk-based microbiological criteria in Belgium

The objective of this study was to do an exercise in risk assessment on Campylobacter spp. for poultry based meat preparations in Belgium. This risk assessment was undertaken on the demand of the competent national authorities as one of the supportive factors to define risk-based microbiological criteria. The quantitative risk assessment model follows a retail to table approach and is divided in different modules. The contamination of raw chicken meat products (CMPs) was represented by a normal distribution of the natural logarithm of the concentration of Campylobacter spp. (ln[Camp]) in raw CMPs based on data from surveillance programs in Belgium. To analyse the relative impact of reducing the risk of campylobacteriosis associated with a decrease in the Campylobacter contamination level in these types of food products, the model was run for different means and standard deviations of the normal distribution of the ln[Camp] in raw CMPs. The limitation in data for the local situation in Belgium and on this particular product and more precisely the semi-quantitative nature of concentration of Campylobacter spp. due to presence/absence testing, was identified as an important information gap. Also the knowledge on the dose-response relationship of Campylobacter spp. was limited, and therefore three different approaches of dose-response modelling were compared. Two approaches (1 and 2), derived from the same study, showed that the reduction of the mean of the distribution representing the ln[Camp] in raw CMPs is the best approach to reduce the risk of Campylobacter spp. in CMPs. However, for the simulated exposure and approach 3 it was observed that the reduction of the standard deviation is the most appropriate technique to lower the risk of campylobacteriosis. Since the dose-response models used in approach 1 and 2 are based on limited data and the reduction of the mean corresponds with a complete shift of the contamination level of raw CMPs, demanding high efforts from the poultry industry, it is proposed to lower the standard deviation of the concentration of Campylobacter spp. in raw CMPs. This proposal corresponds with the elimination of the products that are highly contaminated. Simulation showed that eating raw chicken meat products can give rise to exposures that are 10(10) times higher than when the product is heated, indicating that campaigns are important to inform consumers about the necessity of an appropriate heat treatment of these type of food products.     

Quantitative risk assessment of Cryptosporidium species infection in dairy calves

Cryptosporidium parvum is a zoonotic protozoan that infects many different mammals including cattle and humans. Cryptosporidiosis has become a concern for dairy producers because of the direct losses due to calves not performing well and the potential for environmental contamination with C. parvum. Identifying modifiable control points in the dynamics of infection in dairy herds will help identify management strategies that mitigate its risk. The quantitative risk assessment approach provides estimates of the risk associated with these factors so that cost-effective strategies can be implemented. Using published data from epidemiologic studies and a stochastic approach, we modeled the risk that C. parvum presents to dairy calves in 2 geographic areas: 1) the New York City Watershed (NYCW) in southeastern New York, and 2) the entire United States. The approach focused on 2 possible areas of exposure—the rearing environment and the maternity environment. In addition, we evaluated the contribution of many risk factors (e.g., age, housing, flies) to the end-state (i.e., total) risk to identify areas of intervention to decrease the risk to dairy calves. Expected risks from C. parvum in US dairy herds in rearing and maternity environments were 41.7 and 33.9%, respectively. In the NYCW, the expected risks from C. parvum in the rearing and maternity environments were 0.36 and 0.33%, respectively. In the US scenarios, the immediate environment contributed most of the risk to calves, whereas in the NYCW scenario, it was new calf infection. Therefore, within the NYCW, risk management activities may be focused on preventing new calf infections, whereas in the general US population, cleaning of calf housing would be a good choice for resource allocation. Despite the many assumptions inherent with modeling techniques, its usefulness to quantify the likelihood of risk and identify risk management areas is illustrated.     

生食三文鱼片副溶血性弧菌污染的定量风险评估研究

目的评估上海市生食三文鱼片副溶血性弧菌污染的风险。方法按WHO/FAO危害识别、危害特征描述、暴露评估和风险特征描述4个步骤进行了副溶血性弧菌风险评估,危害识别、危害特征描述资料收集自公开发表的科学文献、报告,暴露评估、风险特征描述应用了监测、膳食调查、生长模型,调整因子、Beta-Poisson剂量反应模型、蒙特卡洛模拟及统计方法。结果在上海市生食被副溶血性弧菌污染的三文鱼片致病的发病概率1—2月、3—5月、6—8月、9—11月分别为8.00×10-7、6.23×10-7、4.14×10-6、8.71×10-6,敏感度分析显示6—11月生食三文鱼中的副溶血性弧菌的污染量对发病概率影响最大。结论上海市生食三文鱼片副溶血性弧菌污染存在比较小的健康风险,夏、秋季控制生食三文鱼片中的副溶血性弧菌的污染量是减少健康风险的关键。     

屠宰过程黄羽肉鸡弯曲菌的定量风险评估

目的 检测屠宰过程黄羽肉鸡弯曲菌阳性率和污染水平,建立屠宰过程黄羽肉鸡弯曲菌的定量风险评估模型,探明其污染的关键风险点。方法 用传统分离鉴定方法和最近似数法（most probable numbers,MPN）定量法对屠宰不同环节弯曲菌阳性率和污染水平进行检测,接着运用描述函数对数据进行拟合,并采用@Risk软件进行重复性检验和敏感性分析。结果 弯曲菌阳性率和污染水平以活鸡肛拭环节最高（53.60％,1.8300 logMPN/m2）,其次为打毛和开膛环节（27.50％,0.5000 logMPN/m2和18.10％,0.0270 logMPN/m2）。根据函数拟合结果建立弯曲菌污染定量风险评估模型,蒙特卡洛（Monte Carlo）模拟分析显示肛拭环节弯曲菌阳性率和污染水平最高(52.92%,1.8896 logMPN),其次是打毛和开膛环节(27.46%,0.4680 logMPN和14.74%,0.4910 logMPN),各个模拟环节数值与分离鉴定结果误差较小（P<0.05）,表明模型具有良好的准确性;敏感性分析获得黄羽肉鸡屠宰过程弯曲菌污染的关键风险点为打毛和开膛环节,相关系数分别为0.77和-0.39,高于其他环节。结论 本研究以屠宰过程黄羽肉鸡弯曲菌为研究对象进行风险评估,成功建立弯曲菌暴露评估模型,且模型具有较好的准确性,同时揭示了屠宰过程弯曲菌防控的关键风险点,为黄羽肉鸡弯曲菌的防控和风险评估奠定基础。     

猪肉及其制品中非伤寒沙门菌定量风险评估研究进展

非伤寒沙门菌是全球重要的食源性致病菌之一,主要通过污染的畜禽食品感染人类。本文综述了国外猪肉及其制品中非伤寒沙门菌定量风险评估研究现状,重点解析常用模型,并分析我国猪肉中非伤寒沙门菌定量风险评估目前存在的挑战,以期为进一步开展相关风险评估提供参考依据。     

Hierarchical Bayesian analysis of censored microbiological contamination data for use in risk assessment and mitigation

Microbiological contamination data often is censored because of the presence of non-detects or because measurement outcomes are known only to be smaller than, greater than, or between certain boundary values imposed by the laboratory procedures. Therefore, it is not straightforward to fit distributions that summarize contamination data for use in quantitative microbiological risk assessment, especially when variability and uncertainty are to be characterized separately. In this paper, distributions are fit using Bayesian analysis, and results are compared to results obtained with a methodology based on maximum likelihood estimation and the non-parametric bootstrap method. The Bayesian model is also extended hierarchically to estimate the effects of the individual elements of a covariate such as, for example, on a national level, the food processing company where the analyzed food samples were processed, or, on an international level, the geographical origin of contamination data. Including this extra information allows a risk assessor to differentiate between several scenario’s and increase the specificity of the estimate of risk of illness, or compare different scenario’s to each other. Furthermore, inference is made on the predictive importance of several different covariates while taking into account uncertainty, allowing to indicate which covariates are influential factors determining contamination.     

Application of elements of microbiological risk assessment in the food industry via a tiered approach

Food safety control is a matter for concern for all parts of the food supply chain, including governments that develop food safety policy, food industries that must control potential hazards, and consumers who need to keep to the intended use of the food. In the future, food safety policy may be set using the framework of risk analysis, part of which is the development of (inter)national microbiological risk assessment (MRA) studies. MRA studies increase our understanding of the impact of risk management interventions and of the relationships among subsequent parts of food supply chains with regard to the safety of the food when it reaches the consumer. Application of aspects of MRA in the development of new food concepts has potential benefits for the food industry. A tiered approach to applying MRA can best realize these benefits. The tiered MRA approach involves calculation of microbial fate for a product and process design on the basis of experimental data (e.g., monitoring data on prevalence) and predictive microbiological models. Calculations on new product formulations and novel processing technologies provide improved understanding of microbial fate beyond currently known boundaries, which enables identification of new opportunities in process design. The outcome of the tiered approach focuses on developing benchmarks of potential consumer exposure to hazards associated with new products by comparison with exposure associated with products that are already on the market and have a safe history of use. The tiered prototype is a tool to be used by experienced microbiologists as a basis for advice to product developers and can help to make safety assurance for new food concepts transparent to food inspection services.     

Quantitative risk assessment of listeriosis due to consumption of raw milk

The objectives of this study were to estimate the risk of illness for raw milk consumers due to Listeria monocytogenes in raw milk sold by permitted dealers, and the risk for people on farms who consume raw milk. Three scenarios were evaluated for raw milk sold by dealers: raw milk purchased directly from bulk tanks, from on-farm stores, and from retail. To assess the effect of mandatory testing of raw milk by regulatory agencies, the number of listeriosis cases per year was compared where no raw milk testing was done, only a screening test to issue a permit was conducted, and routine testing was conducted and milk was recalled if it was L. monocytogenes positive. The median number of listeriosis cases associated with consumption of raw milk from bulk tanks, farm stores, and retail for an intermediate-age population was 6.6 × 10(-7), 3.8 × 10(-5), and 5.1 × 10(-5) cases per year, respective ly. In populations with high susceptibility, the estimated median number of cases per year was 2.7 × 10(-7) (perinatal, i.e., pregnant women and their fetuses or newborns) and 1.4 × 10(-6) (elderly) for milk purchased from bulk tanks, 1.5 × 10(-5 ) (perinatal) and 7.8 × 10(-5) (elderly) for milk from farm stores, and 2.1 × 10(-5) (perinatal) and 1.0 × 10(-4) (elderly) for milk from retail. For raw milk consumed on farms, the median number of listeriosis cases was 1.4 × 10(-7) cases per year. A greater risk of listeriosis was associated with consumption of raw milk obtained from retail and farm stores as compared with milk obtained from bulk tanks. This was likely due to additional time-temperature combination steps in the retail and farm store models, which increased the chances for growth of L. monocytogenes in raw milk. A close relationship between prevalence of L. monocytogenes in raw milk and the values of disease incidence was observed. Hence, a reduction in the number of cases per year in all populations was observed when a raw milk-testing program was in place, especially when routine testing and recalling of milk was conducted.     

Quantitative risk assessment,food chemicals,and a healthy diet

Abstract

Choices about what to eat to improve health and what substances should be prohibited in food to prevent harm both involve judgments that must be made in the absence of definitive information. Scientists and government regulators have refined the limited data on chronic toxicity, especially cancer, from low‐level exposure to chemicals in food by using quantitative risk assessment techniques. Quantitative risk assessment, which produces an exact numerical risk, facilitates decision making about food additives, pesticide residues, and other chemicals present in food. This article examines the feasibility and utility of a similar quantitative approach to the risks and benefits from dietary factors such as fats and fiber. The article concludes that although a more quantitative approach in this area is possible, it would be less useful than it is in regulating potentially carcinogenic food chemicals. Quantitative risk assessment for carcinogenicity is necessitated, in part, by serious gaps in our knowledge about whether and how chemicals induce cancer in people. Although this technique yields a precise measurement of risk, it has no verifiable relationship to what actually happens in the body. Somewhat paradoxically, a greater knowledge of how the diet influences health makes it less necessary to strive for exactness in describing it.     

上海市市售凉拌菜中金黄色葡萄球菌的定量风险评估

目的定量评估市售凉拌菜中金黄色葡萄球菌污染的健康风险,并根据风险评估结果寻找有效的预防措施。方法利用上海市市售凉拌菜中金黄色葡萄球菌检测结果和居民凉拌菜消费习惯及消费量数据,遵循国际食品法典委员会(CAC)提出的危害识别、危害特征描述、暴露评估和风险特征描述四个经典评估步骤,采用Monte Carlo概率评估方法,评估上海市居民由于食用凉拌菜引起的金黄色葡萄球菌肠毒素中毒的风险,并评价潜在的干预措施效果。结果上海市市售凉拌菜中3.39%(21/620)的样品检出金黄色葡萄球菌,平均菌落数为229 CFU/g;居民食用凉拌菜,平均消费频次56.27次/年;每次食用凉拌菜发生金黄色葡萄球菌中毒的概率为0.04%,每年可能的患病例数为51.81万例。结论上海市居民由于食用凉拌菜而导致金黄色葡萄球菌肠毒素中毒存在一定风险,降低零售时凉拌菜中金黄色葡萄球菌的含量、购买后尽快食用和冷藏储存是有效减少凉拌菜中金黄色葡萄球菌肠毒素中毒事件发生的重要干预措施。     

快速微生物定量风险评估工具及其改进在海产品中副溶血性弧菌风险分级中应用

目的使用快速微生物定量风险评估(sQMRA2)工具对海产品中副溶血性弧菌(Vibrio parahaemolyticus,VP)风险开展定量分级,观察预测模型的选择对sQMRA2分级结果的影响。方法利用sQMRA2工具,综合2017年大连市海产品微生物监测数据、海产品消费量调查数据、海产品储存/交叉污染/烹调习惯等专家咨询数据,对大连市不同海产品-致病性VP组合开展定量风险分级。通过改变食品-致病微生物组合的生长和灭活模型表达式对sQMRA2工具加以改进,观察预测模型的改变对分级结果的影响。结果 sQMRA2工具定量风险分级结果发现,虾类-致病性VP组合导致的每餐发病风险和发病人数最高,分别为1. 2×10-5和5 000人。改变生长和灭活预测模型表达式可在一定程度上影响sQMRA2工具的风险分级结果。结论虾类是导致大连市普通人群2017年6～9月感染VP的高风险食品,交叉污染是各种组合导致人体感染VP的主要途径,使用风险分级工具时需要考虑预测模型的影响。