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change in food habits, food processing technologies, and food packaging or distribution systems.
Such concerns must be evaluated and, if reasonable and supported by scientific evidence, appropriate management of the risk must be undertaken.
In practice, risk managers will call upon people with expertise on the particular pathogen and/or food in question and preferably contributing expertise from different scientific or technical areas.
Panels therefore may consist for instance of epidemiologists, public health specialists, risk analysts, food microbiologists and food technologists with knowledge about actual food processing operations, important for the evaluation. The panel will be asked to provide the best information available at that given point in time. Although the complexity of risk evaluations may vary case-by-case, panels typi-cally go through a range of steps that, following international risk analysis frameworks such as that of Codex (CAC 1999) are referred to as hazard identification, hazard characterization, exposure assess-ment and risk characterization. Typically, panels would accumulate available quantitative and qualita-tive data on the food safety problem at hand, develop a view on the risk to a consumer population or sub-populations, identify factors that contribute to risk or could mitigate risk, review options for risk managers to mitigate risk to lower levels possible following a number of scenarios of risk characteriza-tion and risk mitigacharacteriza-tion, and establish recommendacharacteriza-tions for risk managers to consider. The panels will also identify gaps in available data or where there are major aspects of uncertainty or variability in the assessment of the panel and communicate this to the risk managers. In some instances a rough estima-tion of the risks associated with different likely scenarios is sufficient. One approach is to assign rela-tive probability and impact rankings, such as negligible, low, medium, or high, to the factors used to determine likelihood of exposure and likelihood of an adverse outcome. If such a system is used, defi-nitions and rationale for assigned rankings must be clearly described and justified to avoid misinter-pretations of the information by users. An example follows in Chap. 8, where different hazards are ranked into categories dependent on the severity of the disease. The outcome from an expert panel may be to recommend to risk managers one or more measures to control a hazard or, if necessary, ban the product or process. Where appropriate, an expert panel may recommend the establishment of an FSO or PO where their work provides the necessary support that implementing such metrics could be an effective means to enhance consumer protection related to the particular hazard-food combination or the food safety situation under consideration. If there is significant uncertainty, the panels may recommend interim measures that should be taken until gaps in information and data can be addressed.
Chapters 14, 15, 16, 17, 18 and 19 are examples of risk evaluations conducted through the work of expert panels. Further discussion of the role of quantitative risk assessment in development of FSOs and POs is provided in Sect. 2.7.
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While FSOs and POs can obviously be set for any food hazard (e.g. carcinogens, pesticides, toxins, microorganisms), in the context of this book, only hazards of microbial origin are considered.
Therefore, it will be implicit that the FSOs/POs dealt concern microbiological food safety or perfor-mance objectives. The literature on the merits of FSOs/POs as concepts has been building up over the last decade and the range of views is well worth appraising (e.g., Havelaar et al. 2004; Zwietering 2005; Rieu et al. 2007; Whiting 2011; Pitt et al. 2013; De Cesare et al. 2014; Manfreda et al. 2014;
Whiting and Buchanan 2014). Laymen language as well as graphical information on these concepts can be found on the ICMSF website (ICMSF 2006b).
See Chap, 1, Sects. 1.3 and 1.10 for an introduction to current definitions and advocated use of the concepts of FSO and PO. Chap. 1, Sect. 1.11 provides an introduction to related risk metrics (i.e. PC, MC).
2.5.1 Examples of FSOs/POs
An FSO is the maximum frequency and/or concentration of a microbial hazard in a food at the moment that the food is consumer that is considered tolerable for consumer protection. Similarly, a PO signi-fies the tolerable level at a specific earlier point in the food chain, for instance at manufacturing or at retail. It is important to re-emphasize that the primary purpose of an FSO/PO is to translate a public health goal (i.e., a desired level of consumer protection) to measurable attributes that allow industry to set establish an adequate food safety management system at the point of the food supply chain they have responsibility for. Next to that, FSOs may allow comparison between countries related to the level of consumer protection that is expected in the context of food trade.
Although Codex has adopted the concept of FSO/PO and related risk management metrics (CAC 2013a) and established guidelines for their use in risk management (CAC 2007a), these concepts are still rather new and not yet used in food legislation. Some jurisdictions however do mention the terms in their legislation, without specific reference to pathogen-food combinations and/or values for the concepts. Therefore, only hypothetical examples of FSOs or POs can be given to illustrate the concepts.
Some examples of FSOs (all valid at consumption) are:
– The amount of staphylococcal enterotoxin in cheese must not exceed 1μg/100 g.
– The concentration of aflatoxin in peanuts destined for further processing must not exceed 15 μg/kg.
– The level of L. monocytogenes in ready-to-eat foods must not exceed 100 cfu/g.
– The concentration of salmonellae must be less than 1 cfu/100 kg of milk powder.
Examples of POs (valid at specific points in the food supply chain) are:
– The prevalence of Salmonella spp. in neck skin samples taken after the carcass chill step for raw poultry meat carcasses should be ≤10%.
– The level of pathogenic E. coli shall not exceed 1 cfu/10 L when fruit juice is packaged for distribution.
– At the end of manufacture, the level of L. monocytogenes in cold smoked salmon with a 2 week shelf-life at 4 °C should be ≤25 cfu/g assuming 0.6 log cfu growth of the pathogen during shelf-life
– Ready-to-eat foods not supporting the growth of L. monocytogenes must not exceed 100 cfu/g at the time they are placed on the market (i.e. at retail level).
For governments to establish such maximum hazard frequencies and/or levels requires sound quantitative insights in the hazard-food product combination at relevant points in the food supply chain.
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Notably, the above examples of FSOs/POs are presented as “lines in the sand”, focusing on either concentration or prevalence as a tolerable limit for a hazard. While Codex indeed defines FSOs/POs as maximum frequencies and/or concentrations of pathogens that are considered tolerable, various authors have argued that it is important to account for both frequency (prevalence) and concentration (level) of a hazard when articulating an FSO/PO (Zwietering 2005; Havelaar et al. 2004) to provide the relevant industry with proper quantitative targets to be met by implementing adequate food safety management systems.
Moreover, to make the use of risk-based metrics such as FSOs/POs useful in practice, the authority establishing the metric needs to specify the expected level of control beyond a mere “line in the sand”
limit, e.g. by defining what proportion (e.g., 95%, 99%, 99.9%, etc.) of the distribution of possible concentrations must satisfy the test limit so that the FSO (or the PO set by government) is met (van Schothorst et al. 2009). In other words, the proportion of the lot that may be above the nominally
‘acceptable’ level, i.e. the “tolerance” for testing compliance must be specified.
To be able to do this, insight is needed in the distribution of possible contamination concentrations that is typical for the product at hand. Given the expected level of control is articulated, evidently, some units of food will exceed the values specified as the limit in the FSO/PO. Provided that the pro-portion of such units is within the limits expected for the distribution around the mean contamination level required to achieve the FSO/PO, it may be assumed that the food safety management system operates with the expected level of control over the hazard.
For instance, as a hypothetical example, a competent authority has set the value of a PO for E. coli O157 in apple juice at the end of manufacture as: absence of E. coli O157 in 99% of 100 ml units of apple juice. Next, the authority defines the nominally ‘acceptable’ level at 1% (but obviously other values could have been chosen), due to which the PO is then understood as being the 99th percentile of a cumulative frequency distribution of log concentrations. The overall guidance for the industry thus is that in the case no more that 1% of the product units exceed the PO with 99% confidence in the test, then the food safety risk management system is operating as intended. Choosing the value for PO as well as its tolerance are risk management decisions, because they clearly influence the presence of a hazard that is considered acceptable.
The decisions concerning the value(s) for frequency/concentration of a FSO/PO and the expected level of control are also key requirements to allow for deriving a Microbiological Criterion at the point of the FSO/PO that can be used to verify at the operational level, i.e. at the level of batches/lots being produced, whether the food safety management system in place operates as required (van Schothorst et al. 2009; Zwietering et al. 2014, 2015).
Whenever possible, FSOs/POs should be quantitative and verifiable. However, this does not mean that they must be verifiable by microbiological testing. For example, an FSO for low acid canned foods might be established in terms of the probability of a viable spore of C. botulinum being present as fewer than 0.000000000001 per can. It would be impossible to verify this metric by end product testing, but it would be verifiable by measurement of time/temperature protocols that are based on a performance criterion (see Chap. 3).
Where government has stipulated mandatory FSOs/POs, industry should validate that their food safety management system is capable of controlling the hazard of concern to the expected extent, i.e.
by providing evidence that the (set of) control measures underlying the system can consistently meet the FSOs/POs at the relevant scale (CAC 2008a; Zwietering et al. 2010). In addition, during ongoing operation, industry should periodically verify that their food safety management system is function-ing as intended (CAC 2013b). Control authorities may rely on inspection procedures (e.g., physical examination of manufacturing facilities, review of HACCP monitoring and verification records, anal-ysis of samples) to verify the adequacy of food safety management systems adopted by industry in meeting set FSO/PO values. Microbiological criteria are envisaged to play an important role in mak-ing FSOs/POs operational, both from the government as well as the industry perspective (CAC 2007a;
van Schothorst et al. 2009; Zwietering et al. 2010, 2014).
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While FSOs and POs at first glance seem similar to microbiological criteria, they differ in several ways (see Chap. 5). FSOs/POs are not applied to individual lots or consignments and they do not specify sampling plans, number of analytical units, etc. (Zwietering et al. 2014). Most often, POs are used to define the level of control that is expected for a food operation and can be met through the implementation of GMP/GHP and HACCP systems and application of performance criteria, process/
product criteria and/or acceptance criteria, whereas the FSOs provide for an outcome- oriented target for the food supply chain as a whole (see Chap. 3).
2.5.2 The Use of FSOs and POs
Through the articulation of FSOs and/or POs, as appropriate, authorities set-out to communicate clearly to industry what is expected of foods produced under properly managed operations. At the same instance, flexibility is given to industry to use different production, manufacturing, distribution, marketing, and preparation approaches for meeting the risk-based metrics in accord to their technical capabilities and preferences (CAC 2007a).
Where setting a FSO is considered a feasible risk management option, the purpose of an FSO set by a competent authority of a country may be to
– relate the expected level of operational control over a particular hazard associated to a certain food to a policy level of currently achieved public health protection that is relevant for local and or international trade, i.e. an ALOP/TLR.
– drive necessary improvement in the food safety status of a pathogen-product combination on the basis of a forward looking public health goal or the need to mitigate a food safety status that is deemed unacceptable, for instance targeting more stringent food safety control(s) by the industry or change in behavior of consumers
In both cases, industry is expected to put in place operational food safety control systems that deliver a level of food safety in line with the FSO, by establishing one or more appropriate POs, PCs and other control measures on the basis of coordinated interaction various food business operators in the food supply chain of concern.
POs may be set by government to guide a particular industry in establishing appropriate control measures at specific points in the food supply chain for instance in such cases where the government considers that this industry typically may not have the means to establish such measures themselves or where these measures are of critical importance to the performance of the overall food supply chain.
Competent authorities may include reference to FSOs/POs in their food standards or guidelines, but since the FSO specifically relates to the time of consumption, it is unlikely that a competent authority would use FSOs as regulatory metrics at the operational level due to the difficulty in verify that control at this point in the food supply chain is being met. Therefore, it is more likely that for operational purposes, competent authorities articulate POs where appropriate to communicate to the industry and other stakeholder what their risk-based food safety expectations are at specified points in food supply chains.
As agreed at the level of Codex Alimentarius (CAC 2007a), setting FSOs is the sole prerogative of competent authorities, who may base the values for this metric on explicit or even implicit public health targets, epidemiological data or insight in the hazard characterization for the hazard at hand.
Likewise, POs can be derived from public health targets or using other relevant tools/information on the dynamics of a hazard between the point of consumption and the upstream point in the food supply chain where a PO is considered as a feasible risk mitigation option. Use of quantitative risk assess-ment approaches developed for the relevant pathogen in a particular food, preferably developed for/
by a competent authority, has been advocated by several authors for linking FSOs and/or POs to ALOPs (e.g. Nauta and Havelaar 2008; Tenenhaus-Aziza et al. 2014; Walls 2006; Zwietering 2005).
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Industry may find it useful to establish one or more POs along the food supply chain to coordinate overall management and ensure that, where a FSO has been set by government, the food safety status of a food expected at the point of consumption is duly achieved. Individual food business operators working in and along the food supply chain may choose to use any of the methods that competent authority use when deriving POs from FSOs. Food business operators can establish a PO on the basis of either an FSO set by a competent authority, or from an evaluation (usually quantitative) of the fate of the hazard in the specific food supply chain, ultimately resulting in an estimate of the risk (Zwietering et al. 2014).
Thus, the concepts of FSO and PO have very practical value and can be commonly understood and applied by industry and regulators, alike. Since FSO/PO do not specify how compliance is achieved, the concepts offers considerable flexibility to food business operator(s) involved in the particular food supply chain. This would enable one operator to use formulations, equipment and procedures that differ from other operators as long as the FSO/PO is met. Furthermore, there can be a high level of confidence in the acceptability of food being produced by operations that have been designed and validated to meet the relevant FSOs/POs. Foods from such operations need seldom be tested for the relevant pathogen(s) to verify compliance. Instead, verification can be achieved through record review and observation of GMP/GHP and HACCP (see Chap 4).
Since the adoption of the concepts of FSO and PO, many studies on their application for a diverse range of pathogen-product combinations have been published through peer review processes (e.g.
Anderson et al. 2011; Crouch et al. 2009; De Cesare et al. 2014, 2015; Gkogka et al. 2013; Manfreda et al. 2014; Membre et al. 2007; Nauta and Havelaar 2008; Paulsen et al. 2009; Perni et al. 2009; Sosa et al. 2011; Skjerdal et al. 2014; Tenenhaus-Aziza et al. 2014; Tromp et al. 2010; Tuominen et al.
2007; Uyttendaele et al. 2006; Walls 2006) or are available in the public domain (e.g. Buchanan et al.
2006; DaPaola et al. 2006; Butler et al. 2006).
In summary, establishing risk-based metrics such as FSO and PO offers many advantages for both control authorities and industry because they can be used to:
– translate a public health goal to a measurable level of control upon which food processes can be designed so the resulting food will be acceptable
– validate food processing operations to ensure they will meet the expected level of control – assess the acceptability of a food operation by control authorities or other auditors – highlight food safety concerns, separate from quality and other concerns
– force change in a food commodity and improve its safety
– serve as the basis for establishing microbiological criteria for individual lots or consignments of food when its source or conditions of manufacture are uncertain.
It is not necessary to establish an FSO for all foods or all known hazard-food combinations. In some cases the potential microbiological hazards associated with a food represent so little risk at consumption that an FSO is not needed (e.g., granulated sugar, sweetened condensed milk, most breads, pineapple, carbonated beverages). In other cases the sources of a pathogen are so variable that identifying the foods for which FSOs should be set is not possible. An example of the latter is shigel-losis which can be transmitted by many routes, most of which are more important than food (e.g., water, person-to-person), and it is unpredictable which specific food may next be implicated.
The FSO also becomes useful when the safety of new products is evaluated. When placing new products or novel foods on the market, their safety should be substantially equivalent to existing simi-lar products.
Investigation of foodborne disease continues to identify new pathogens and new pathogen-food combinations. The emergence of listeriosis as a foodborne disease during the 1980s as a result of outbreaks traced to coleslaw and Mexican-style cheese is an example of a recently recognized food-borne pathogen. The finding that non-pasteurized juices and raw vegetables can be vehicles for E. coli O157:H7 is an example of a new pathogen-food combination. In such situations a quick decision may
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be necessary to prevent more cases or outbreaks. Establishment of an interim FSO could be an initial step to communicate to the food industry, or exporting countries, the maximum level of a hazard at consumption that is considered to be acceptable. As further knowledge about the hazard, the food and conditions leading to illness become available and effective control measures can be determined, that interim FSO can be adjusted.
As noted before, FSOs/POs can be used to force change in an industry and enhance the safety of certain products. Many examples could be cited where epidemiologic data indicated certain foods were linked to foodborne illness. In response to this information governments used various mechanisms at their disposal to bring about the changes necessary to reduce or eliminate the risk of disease. In some cases, modifications in primary production or manufacturing practices may have been necessary, including the adoption of new or more reliable technologies, while in other situations risk could be effectively reduced for instance by consumers or food service operations changing behavior or prac-tices. The establishment of an FSO/PO could be used by risk managers in government to communicate to impacted stakeholders the level of control expected and, thereby, forcing the required change.
The WTO/SPS agreement recognizes that governments have the right to reject imported foods when health of the population may be endangered. The criteria used to determine whether a food is considered to be safe or unsafe should, however, be clearly conveyed to the exporting country (trans-parency) and should be scientifically sound. Integral to the treaties is the concept of “reasonableness”, a requirement that is inherent to the establishment of realistic FSOs. An exporting country can contest an FSO that does not reflect conditions existing in the importing country, and argue that the FSO is an unjustified trade barrier. However, because an FSO also reflects commercialization conditions, eating habits, preparation and use practices, FSOs may vary considerably between countries. Nevertheless, a country cannot demand that imported foods are “safer” than similar domestically produced foods. For example, if the tolerance for aflatoxin in domestically grown and processed peanuts is 15 μg/kg, then imported peanut products cannot be rejected if contaminated to the same or a lesser concentration.
FSOs provide a means for implementing the concept of equivalence in Article 4.1 of the Agreement on Sanitary and phytosanitary (SPS) measures of WTO.” Members (countries) shall accept the SPS mea-sures of other Members as equivalent, ..., if the exporting Member objectively demonstrates ... that its measures achieve the importing Member’s appropriate level of sanitary or phytosanitary protection.”