食源性致病微生物风险管理与控制

介绍食品安全管理的框架方法,包括采样和微生物检验,概述良好卫生规范及危害分析关键控制点系统如何达到某一食品或加工过程的特定食品安全目标（food safety objective,FSO）。FSO是企业在特定食品或食品操作中选择并实施控制危害的措施,为管理机构制定并实施监督程序以评估企业采纳管理措施的适当性,以及在不同国家监督程序的等同性方面的定量提供了科学基础。微生物检验是食品安全管理的有效手段,然而应在了解其局限性及其应用的益处和目的的情况下选择和应用微生物检验。食品工业制定有效的管理系统控制食品中特定的危害,其对于负有评估企业是否已经建立并充分实施食品安全管理系统职责的管理机构来说同样有效。     

食品卫生微生物学指标设定上的国内外差异

制定微生物指标不仅是为了检验食品终产品的卫生质量，而且在国际上广泛用于食品生产、运输和销售等全过程的监测和HACCP的验证。在我国食品卫生标准体系中，有关微生物检验的采样、检测方法以及指标表述方面与国际通行做法上有较大差距。通过介绍国际食品法典委员会制定微生物学指标的原则和要点，提出完善我国食品卫生标准体系的建议。     

Performance standards and meat safety--developments and direction

Performance standards have been developed to express, for regulatory purposes, an acceptable level of food safety afforded by either a product or a process. These performance standards have reflected the development of scientific thought on food safety management through setting of microbiological criteria, implementing hazard analysis critical control point (HACCP) systems, process control and risk-based management. In meat safety management, some performance standards reflect current risk-based thinking which sets objectives and/or criteria and allows freedom on how those objectives/criteria can be met. However, many performance standards do not reflect current thinking and some perpetuate the idea that meat can be consumed with zero risk.     

Use of microbial data for hazard analysis and critical control point verification--Food and Drug Administration perspective

This paper examines the role that the microbiologist and microbiological testing play in implementing hazard analysis and critical control point (HACCP) programs. HACCP offers a more comprehensive and science-based alternative for controlling food safety hazards compared with traditional sanitation programs based upon good manufacturing practices. Controlling hazards under an HACCP program requires a systematic assemblage of reliable data relating to the occurrence, elimination, prevention, and reduction of hazards. These data need to be developed in a transparent environment that will ensure that the best scientific methodologies have been employed in developing the needed data. The two mechanisms used in HACCP to assess the adequacy of the database are validation studies and the verification assessments. Microbiological testing is an important mechanism for collecting data used in developing and implementing an HACCP plan. Microbial sample data can help establish standard operating procedures (SOPs) for sanitation, assess the likelihood of the occurrence of hazards, establish critical limits, and assess the validity of the HACCP plan. The use of a performance standard to assess whether microbiological hazards have been reduced to an acceptable level creates an especially important use for microbial analysis. Microbial testing is also useful in implementing an HACCP plan by helping to monitor the effectiveness of sanitation SOPs, the compliance of incoming ingredients with safety criteria, the safety of product being held for corrective action, and the safety of the finished product. The verification audits demonstrate that all control measures have been applied as designed in the HACCP plan. Although auditing HACCP records is the primary means of verification, microbial sampling can play an important role as well.     

Use of microbiological indicators for assessing hygiene controls for the manufacture of powdered infant formula

Microbiological testing for various indicator microorganisms is used extensively as a means of verifying the effectiveness of efforts to ensure the microbiological quality and safety of a wide variety of foods. However, for each use of an indicator organism the underlying scientific assumptions related to the behavior of the target microorganism, the characteristics of the food matrix, the details of the food manufacturing processes, environment, and distribution system, and the methodological basis for the assay must be evaluated to determine the validity, utility, and efficacy of potential microbiological indicator tests. The recent adoption by the Codex Alimentarius Commission of microbiological criteria for powdered infant formulae and related products provides an excellent example of an evidence-based approach for the establishment of consensus microbiological criteria. The present article reviews these criteria and those of various national governments in relation to emerging principles for the evidence-based establishment of effective indicator organisms.     

Aerobic plate counts as a measure of hazard analysis critical control point effectiveness in a pork processing plant

A hazard analysis critical control point (HACCP) system was designed to identify specific hazards so that preventive and control measures to ensure the safety of a food could be implemented. Microbiological data generated through sampling were used to characterize the hygienic performance and to validate and verify the various HACCP plans. Aerobic plate counts (APCs) often are chosen as an indicator of the effectiveness of HACCP plans, because data for all aerobic bacteria are more easily collected than are data for pathogens of concern or other indicator organisms. However, it is not clear whether APCs are useful in verifying that a HACCP plan is working satisfactorily. In this study, APC data were collected from one pork-cutting plant in Korea both before and after the company initiated its HACCP plan. These APC data were used to compare microbiological differences and to determine the effect of any changes before and after implementing the HACCP plan. For this pork plant, after the HACCP plan was implemented the proportion of samples exceeding the 3 log CFU/cm2 limit dropped from 73.39 to 4.29% for the overall process. These results indicate that this plant improved its hygienic performance considerably and that the HACCP plan was an effective and valuable tool for achieving this improvement. The APC data were sufficient for validation and verification of the HACCP system that was successfully implemented to improve hygienic performance.     

Assessing the hygiene of pig carcasses using whole-body carcass swabs compared with the four-site method in EC Decision 471

An investigation was carried out in a pig abattoir to determine the microbiological status of carcasses being produced after slaughter and dressing. The carcasses were sampled in accordance with EC Decision 471 in relation to the application of hazard analysis critical control point (HACCP) criteria to the slaughter of animals. In this regard, four sites on the animals were examined on five consecutive carcasses during each of 10 visits for the presence of total viable counts and Enterobacteriaceae. A comparison of the EC four-site method, with a whole-body swab technique, as a means of measuring carcass contamination found that the two methods gave significantly different results for both groups of organisms. A comparison of the mean of the individual data from the four sites with the data from the pooled samples revealed that there was a poor relationship between the two. Samples may be taken by excision or swabbing and allocated to three categories of process control, which, in turn, are based on microbiological criteria that are different, depending on whether sampling is by excision or swabbing. The influence of these changes in microbiological criteria is discussed in relation to the categorization of samples as acceptable, marginal, or unacceptable and the influence this has on process control. Finally, the proposed introduction of Salmonella as a safety indicator in the EC HACCP system is discussed.     

Industry perspectives on the use of microbial data for hazard analysis and critical control point validation and verification

Microbial testing is an essential element in validation of critical limits identified within a hazard analysis critical control point (HACCP) plan. Without appropriate validation there is no assurance that the plan will control the hazards of concern. Once critical control points have been validated to effectively prevent, reduce, or eliminate hazards, application of routine testing for pathogens in finished product becomes an ineffective means to assure process control and therefore safety of the product. The occurrence of a pathogen in a product produced under an effective HACCP plan is so rare that sampling protocols are not capable of finding the needle in the haystack. Quantitative indicators can provide a much more effective tool for verifying that HACCP is properly implemented. Choice of appropriate indicators is product and process specific. In certain applications, finished product testing for even indicator organisms provides no meaningful data for verification of HACCP (e.g., canned products). Tests chosen should provide meaningful information that directs resources toward prevention and improvement of the system.     

An overview of microbial food safety programs in beef, pork, and poultry from farm to processing in Canada

Canada's vision for the agri-food industry in the 21st century is the establishment of a national food safety system employing hazard analysis and critical control point (HACCP) principles and microbiological verification tools, with traceability throughout the gate-to-plate continuum. Voluntary on-farm food safety (OFFS) programs, based in part on HACCP principles, provide producers with guidelines for good production practices focused on general hygiene and biosecurity. OFFS programs in beef cattle, swine, and poultry are currently being evaluated through a national recognition program of the Canadian Food Inspection Agency. Mandatory HACCP programs in federal meat facilities include microbial testing for generic Escherichia coli to verify effectiveness of the processor's dressing procedure, specific testing of ground meat for E. coli O157:H7, with zero tolerance for this organism in the tested lot, and Salmonella testing of raw products. Health Canada's policy on Listeria monocytogenes divides ready-to-eat products into three risk categories, with products previously implicated as the source of an outbreak receiving the highest priority for inspection and compliance. A national mandatory identification program to track livestock from the herd of origin to carcass inspection has been established. Can-Trace, a data standard for all food commodities, has been designed to facilitate tracking foods from the point of origin to the consumer. Although much work has already been done, a coherent national food safety strategy and concerted efforts by all stakeholders are needed to realize this vision. Cooperation of many government agencies with shared responsibility for food safety and public health will be essential.     

食品安全微生物学指示菌国内外标准应用的比较分析

菌落总数、大肠菌群、大肠埃希菌、肠杆菌科作为食品安全微生物限量的指示菌在国内外标准中的应用不尽相同.本文通过比较我国与欧盟、澳大利亚、新西兰、加拿大和香港地区的相关食品指示菌标准,为制定我国的食品安全微生物标准提供技术依据.     

Decreasing variation in the eating quality of beef through homogenous pre- and post-slaughter management

Even though microbiological standards have been promulgated for many decades, their utility has sometimes been questioned, and this is one reason that performance standards associated with programs like HACCP in processing plants and now in other food industries have been espoused. The public has an increasing concern over food safety and perceives a zero tolerance policy (i.e. no pathogens in a sample of food) and strict enforcement with punitive consequences for failure to comply is the answer to making food safer. At present, there is no clear connection between government policy and a reduction in foodborne illness. Although national disease statistics may show gradual declines over long periods for some pathogens associated with food, other problems, including new pathogens, tend to emerge. International bodies and some governments, however, are increasingly considering adopting a risk-based approach to managing a food supply, with the potential for introducing the Acceptable Level of Protection (ALOP) and Food Safety Objectives (FSOs) concepts. These make it possible to see a connection between a goal for disease reduction and what industry must do to accomplish this with specific objectives through performance standards and microbiological testing. However, it may not be easy to apply this approach for all types of industries and pathogens and in developing countries.     

Microbiological conditions of mechanically tenderized beef cuts prepared at four retail stores

A group of 25 retail cuts of mechanically tenderized beef prepared during usual commercial operations at store facilities were obtained from each of four retail stores. Aerobes, coliforms, Escherichia coli and organisms that formed black or grey colonies on Harlequin agar (HA), a medium formulated for the recovery of Listeria, were enumerated in samples from the surfaces and the deep tissues of cuts. For the four groups of cuts, the mean numbers of aerobes on the surfaces of cuts differed by <1 log unit, but the numbers of aerobes recovered from the deep tissues differed by up to 2 log units. Few coliforms, E. coli or organisms that formed black or grey colonies on HA, which were mostly staphylococci, were recovered from surfaces and very few or none were recovered from deep tissues. Meat from the stores which provided product with the least or most bacteria in the deep tissues were cooked to maximum central temperatures that ranged from >63 to <68 degrees C. Cooking reduced the numbers of aerobes in the deep tissues of most portions to <1 log cfu/10 g. Cooking to a medium rare condition may be adequate for assuring the microbiological safety of mechanically tenderized beef that is prepared without excessive contamination of deep tissues.     

Accelerated methods for the microbiological quality control of food products in the critical control point system in the analysis of the hazard factor

The rapid microbiological methods of quality control food in the HACCP systems. The paper contain the summary of the hazard analysis control point concept for the control of food microbiological safety. It characterises the express methods that can detect and identify the Food Poison Organisms, including the methods for the rapid detection and enumeration of microorganisms by means of a new impedance measuring systems, molecular-biologic methods and DNA-diagnostic methods.     

Role of microbiological guidelines in the production and commercial use of milled cereal grains: a practical approach for the 21st century

A contemporary survey of the microbiological profile of five milled cereal grains-wheat, corn, oats, whole wheat, and durum-was conducted largely from 2003 to 2005, with routine laboratory data obtained by North American dry-milling operations. When compared to data reported in the previous century, the contemporary data showed similar or reduced quantitative counts for indicator tests (e.g., total aerobes, yeasts, molds, coliforms, and Escherichia coli) as well as a substantially lower incidence of salmonellae. The implementation of modern management systems for the control of food quality and safety, i.e., good agricultural practices, good manufacturing practices, and the hazard analysis critical control point system, together with the excellent microbiological profiles, has eliminated the need for microbiological specifications and lot acceptance criteria for milled cereal grains. Instead, microbiological monitoring guidelines, such as the periodic testing of aerobic plate counts and mold counts, can be used to verify compliance with the requirements of food quality and food safety management systems.     

基于HACCP体系浅析食品微生物定性检测中的风险管理

食品微生物中致病菌的检测多为定性检测,为了确保检测结果准确性,防止假阳性或者假阴性结果的出现,微生物实验室应对实验室和食品微生物定性检测流程中存在的风险进行风险管理。本文基于HACCP原理对微生物定性检测中的关键控制点进行分析及评估,建立监控系统,提出预防措施,最终形成HACCP计划表,降低或者避免风险的产生,提高检测结果准确度和可靠性。     

大型国际综合性运动会运动员村食品卫生管理模式的研究

为给北京 2 0 0 8年奥运会食品卫生管理提供科学依据 ,应用危险性分析和HACCP原则对2 0 0 1年北京大运会大运村食品卫生进行管理 ,食品合格率达到较高水平 ,实现了杜绝食物中毒的既定目标 ,提示危险性分析和HACCP原则可在大型国际综合性运动会运动员村食品卫生管理中发挥有效作用。     

Microbiological sampling of swine carcasses: a comparison of data obtained by swabbing with medical gauze and data collected routinely by excision at Swedish abattoirs

Swab sample data from a 13-month microbiological baseline study of swine carcasses at Swedish abattoirs were combined with excision sample data collected routinely at five abattoirs. The aim was to compare the numbers of total aerobic counts, Enterobacteriaceae, and Escherichia coli, recovered by swabbing four carcass sites with gauze (total area 400 cm2) with those obtained by excision at equivalent sites (total area 20 cm2). The results are considered in relation to the process hygiene criteria that are stated in Commission Regulation (EC) No 2073/2005. These criteria apply only to destructive sampling of total aerobic counts and Enterobacteriaceae, but alternative sampling schemes, as well as alternative indicator organisms such as E. coli, are allowed if equivalent guarantees of food safety can be provided. Swab sampling resulted in higher mean log numbers of total aerobic counts at four of the five abattoirs, compared with excision, and lower or equal standard deviations at all abattoirs. The percentage of swab and excision samples positive for Enterobacteriaceae at the different abattoirs ranged from 68 to 100% and 15 to 24%, respectively. Similarly, the percentages of swab samples that were positive for E. coli were higher than the percentages of positive excision samples (range 52 to 84% and 3 to 14%, respectively). Due to the low percentage of positive excision results, the mean log numbers of Enterobacteriaceae and E. coli were only compared at two and one abattoirs, respectively, using log probability regression to substitute censored observations. Higher mean log numbers of Enterobacteriaceae were recovered by swabbing compared with excision at one abattoir, whereas the numbers of Enterobacteriaceae and E. coli did not differ significantly between sampling methods at one abattoir. This study suggests that the same process hygiene criteria as those stipulated for excision can be used for swabbing with gauze without compromising food safety. For monitoring of low numbers of Enterobacteriaceae and E. coli, like those found on swine carcasses at Swedish abattoirs, the results also show that swabbing of a relatively large area is superior to excision of a smaller area.     

Microbiological safety evaluations and recommendations on sprouted seeds. National Advisory Committee on Microbiological Criteria for Foods

In 1997, the National Advisory Committee on Microbiological Criteria for Foods (NACMCF/the Committee) was asked to review the current literature on sprout-associated outbreaks: identify the organisms and production practices of greatest public health concern: prioritize research needs: and provide recommendations on intervention and prevention strategies. In response to this charge, the Fresh Produce Work Group (FPWG) documented the relevant epidemiology and microbial ecology of sprout-associated outbreaks and reviewed current industry practices and initiatives related to the growing of seed and the production of sprouts. Sprouts have been identified as a special problem because of the potential for pathogen growth during the sprouting process. If pathogens are present on or in the seed, sprouting conditions may favor their proliferation. There is no inherent step in the production of raw sprouts to reduce or eliminate pathogens. Contaminated seed is the likely source for most reported sprout-associated outbreaks. Research has been initiated on methods to reduce or eliminate pathogenic bacteria on seeds and sprouts and some treatments show promise. However, to date, no single treatment has been shown to completely eliminate pathogens under experimental conditions used. Finally, the Committee found that, at the time of the charge, there was a lack of fundamental food safety knowledge along the continuum from seed production through sprout consumption. More recently, many have become aware of the potential for this food to be a vehicle for foodborne illness and the need for appropriate controls: however, such awareness is not universal. Although seed appears to be the most likely source of contamination in sprout associated outbreaks, practices and conditions at the sprouting facility may also impact on the safety of the finished product. In recent sprout-associated outbreak investigations, facilities associated with outbreaks did not consistently apply seed disinfection treatments prior to sprouting. Conversely, facilities that used seed from the same lot as an implicated facility, but had not been associated with reported illnesses, appear to have been consistently using seed disinfection treatments, such as 20,000 ppm calcium hypochlorite, to disinfect seed prior to sprouting. The Committee has developed a number of specific recommendations, including: 1. The knowledge of all interested parties pertaining to the microbiological safety of sprouted seeds must be enhanced; government and industry should develop education programs for seed and sprout producers on basic principles for microbiological food safety, good agricultural practices, good manufacturing practices, and hazard analysis and critical control point (HACCP) systems. 2. Good agricultural practices should be systematically implemented to reduce the potential for microbial contamination of seeds for sprout production. 3. Seed cleaning, storage, and handling practices that minimize the potential for microbial contamination should be developed and implemented. 4. Seeds should be treated with one or more treatments that have been shown to reduce pathogenic bacteria that may be present. Intervention strategies that deliver less than a given reduction (at this time, 5-log) in levels of Salmonella spp. and enterohemorrhagic Escherichia coli O157 should be coupled with a microbiological testing program. 5. Establish good manufacturing practices and food safety systems, including regulatory oversight, microbial testing, adoption of HACCP, and improved traceback, that systematically look for means to prevent seeds from serving as the vehicle for foodborne disease, and 6. Conduct research related to the microbiological safety of sprouted seeds, particularly in the areas of pathogen reduction or elimination, sources of contamination and its prevention, and preventing or retarding pathogen growth during sprouting.     

Elaboration of microbiological guidelines as an element of codes of hygienic practices for small and/or less developed businesses to verify compliance with hazard analysis critical control point

Effective assurance of microbiological food safety practices in small and/or less developed businesses is not yet resolved. Although a start has been made by drafting hygiene codes, feasible methods for verifying manufacturing processes that rely on strict and meaningful criteria to be applied to process points are still lacking. This investigation is a model study with various types of ready-to-eat foods aimed at verifying adequate processing for safety and subsequent meticulous hygienic handling and safe storage of foods in small and/or less developed businesses by the use of quantitative methods for selected indicator organisms, as standardized by the International Organization for Standardization. The manufacture of the foods that were used in this study invariably included (i) a heat processing step that ensured a level of lethality of nonsporing organisms at least equivalent to the reduction of such organisms attained in the pasteurization of milk and (ii) effective means of prevention of postprocess recontamination and recolorization. The results of this study indicate that simple microbiological criteria used for this purpose, including aerobic mesophilic colony (standard plate) counts, Enterobacteriaceae counts, and, in some instances, enumeration of yeast propagules, allow adequate verification of good practices throughout. This verification through monitoring of samples taken during processing in small and/or less developed businesses was found to be an attractive alternative to the conventional examination of end products.     

The HACCP concept: identification of potentially hazardous micro-organisms

The hazard analysis critical control point (HACCP) concept is becoming an increasingly important aspect of Good Manufacturing Practices in safe food production. HACCP is a systematic means of controlling any microbiological hazard that may arise in a food processing or handling operation and aims to identify problems before they occur. The first step is to establish the hazardous organisms associated with a particular food product. An approach is presented here that permits identification of potentially hazardous bacteria. It is based on a list of all those bacteria that are known to cause foodborne disease in man. Following an evaluation of raw materials, the production process, possibilities for contamination etc., deletions from or additions to the list are made. For the organisms that are retained, it is necessary to determine whether or not they have caused foodborne disease involving identical or related food products. Where this is not the case, the organism can be deleted. In cases of doubts, an organism should not be deleted from the list of potentially hazardous agents. A more evaluation of the hazards will be made during the identification of critical control points (CCPs) and the setting of control criteria at each CCP.