pretreatment
6.6 The HACCP study
As a preventative approach to ensuring consumer safety, the HACCP concept of food safety management fits with QA philosophy generally and the operation of HACCP systems should fall within the scope of a grower’s QA strategy. The resources needed to develop, implement and maintain HACCP systems should be furnished as part of a grower’s overall QA provision. Though the employees of a business can directly influence the safety of products through their actions, the business as a whole carries a corporate responsibility for assuring no harm comes to consumers through eating their products. The ultimate responsibility for food safety and consumer protection in any food business should rest with top management (the chief executive or someone of equivalent status) who should also be responsible for ensuring that the resources for HACCP are adequate. This is necessary even though top management may have little direct contact with the mechanics of QA and food safety management. Inadequate resources in terms of qualified personnel, physical resources and time can be one of the key problems faced by food businesses in carrying out HACCP studies and in implementing, operating and maintaining HACCP systems. Without the commitment to provid-ing adequate resources there is little point in embarkprovid-ing on a HACCP study.
Ensuring this commitment is a primary function of top management.
The HACCP study defines the basis for the systems of consumer protection against foodborne hazards established by food businesses, such as those operated
by growers. It consists of a 12-stage process which aims to (a) analyse hazards, that is, identify the hazards most likely to be associated with a given product and the process by which it is produced, and (b) establish critical control points, that is, places in the production process where methods for the control of hazards can be applied.
6.6.1 Stage 1: Assemble the HACCP team (and define the scope and terms of reference of the study)
A HACCP team should be assembled and the scope and terms of reference of the study should be defined. The team should be multidisciplinary, containing members with the expertise required to deal with the range of issues that will arise during the study. A microbiologist (or someone with an adequate knowledge of microbiology) is usually an essential member of the team as microbial hazards must be appraised. It is also important to include members who have expertise in the crop production and pretreatment operations to be considered in the study.
If the appropriate expertise is not available within an organization it may be nec-essary to use, for instance, the services of a consultant. The HACCP study should relate to a given crop product, its associated production process and any subse-quent pretreatment processes, as relevant. The hazards arising in the production of a crop and the way they arise may be almost unique to that crop in the place where it is grown. It cannot be assumed that the factors affecting the production of a crop in one place will be identical to those affecting production of the same crop in another place. The use of generic HACCP plans is sometimes advocated as a short cut to the development of HACCP systems. Generic HACCP plans can be useful as sources of ideas and information, but the adoption of these plans can be dangerous as local factors may not be considered and hazards may be over-looked. It is better and safer to develop HACCP plans and systems locally, and avoid importing errors and misconceptions through the use of generic plans.
The scope of the study should be defined, stating the crop product to be con-sidered by the study and identifying the production processes involved. The scope of the study sets a limit on the HACCP plan to be developed, defining where it starts and finishes. This is important, especially where complex production processes are concerned. It can be simpler (and safer) to break down processes into component operations and carry out a series of HACCP studies on ‘bite-sized chunks’, which link together later to form the overall HACCP system. For instance, seed preparation and propagation may form one HACCP study, with crop production, harvesting and post-harvest pretreatments forming others. When carrying out a HACCP study it can be tempting to consider the three categories of hazard – microbiological, chemical and physical – at the same time. This can lead to complications and by defining the terms of reference of the study an agreement is made to limit the study to, for example, microbial hazards, with the intention of considering chemical and physical hazards later. Knowledge gained during an initial study can be transferred to later studies, thereby reducing sub-sequent workloads.
6.6.2 Stage 2: Describe the product
A complete description of the product should be developed. The aim is to provide information that will enable the identification of hazards associated with intrin-sic characteristics of the product itself, or from conditions concerning, for example, its packaging, storage, transport and distribution. In the manufacture of formulated foods, intrinsic preservation factors such as pH, salt-in-moisture content and water activity (aw) are important to consider as they relate to the sur-vival and growth of bacterial pathogens. In the case of fruit and vegetables such factors may be of lesser value, though, for instance, characteristics of the product resulting from harvesting, post-harvest handling and storage, and so on, may be relevant to the presence or development of hazards and should be considered.
Similarly, the packaging of a crop may be defined as a part of the final product and should be assessed for its potential to be hazardous, for example, plastic bags can represent a suffocation risk for young children, or give rise to hazards, and the use of wooden boxes and pallets should be assessed in this respect. Also of importance may be the use of specific storage conditions, such as modified atmos-phere storage, which might give rise to the development of hazards, for example anaerobic bacterial pathogens.
In describing the product, reference should be made to product specifications, for example specifications agreed with customers defining the quality and food safety parameters to which the product should conform. Crop production methods may result in products carrying pesticide residues, or potentially being contami-nated with bacterial pathogens, and limits for both should be set in specifications.
Other factors which may be specified are, for instance, physical hazards e.g.
stones or fragments of wood resulting from harvesting operations and the use of harvested product management chemicals such as sprout suppressant compounds used on potatoes.
6.6.3 Stage 3: Identify the intended use of the product
The intended use of the product should be identified. The primary purpose is to identify whether the way the product is used (by a processor or consumer) could give rise to a hazard and to identify any sensitive groups for whom the product might be intrinsically harmful. It is also important to identify whether specific market requirements need to be observed. For example, only organic products or products which have not been genetically engineered may be supplied to certain markets, and some markets require certain varieties of produce, like potatoes suit-able for crisp and snack food production (though these are not necessarily food safety issues). Fruits eaten without washing before sale and which might not be washed before consumption may be harmful if contaminated by pathogenic bac-teria, or by high levels of pesticides or other toxic agrochemical compounds. For example, peaches and nectarines consumed whole, without removal of the skin, may have the potential to poison consumers in the event that the surface of the product is contaminated with harmful substances. Similarly, salad crops such as lettuce may not be adequately washed by consumers and may, therefore, present
the risk of food poisoning if the crops have been contaminated by enteropatho-genic bacteria through the use of improperly composted manure or faecally con-taminated irrigation water. In the case of crops destined for processing, the customer should be aware of the possible presence of contaminants, probably through agreement of the product specification. The customer then should be responsible for ensuring that hazards in the form of known contaminants are controlled. For example, some manufacturers of minimally processed prepared salads use chlorinated water to wash salad crop materials to reduce levels of con-tamination by one or two log cycles, and exercise controls that prevent cross-contamination (Carlin and Nguyen, 1999).
When fruit and vegetables are sold to consumers for use in the preparation of meals or for direct consumption the responsibility lies with the producer, and also retailers, to ensure that the products are free from hazards or that consumers are advised accordingly. Crop production methods should ensure that, for instance, pesticide residues do not exceed MRLs, but for additional confidence in the safety of the product, and the ability of the producer and retailer to demonstrate due diligence, it may be that some products are washed to reduce chemical residue levels, for example in the case of some apples, oranges and potatoes. Where con-trols are not implemented the responsibility for control falls to consumers who should be warned of the possible existence of a hazard so they can take the appropriate course of action. This is the principle seen in the example of food products which contain, or may contain, nuts and which are labelled to warn con-sumers suffering from nut allergy, who fall into the category of ‘sensitive groups’.
It is necessary to identify sensitive consumers who may be harmed by charac-teristics of the product which do not normally represent a hazard to most con-sumers. Such consumers include children, pregnant women, old people and people whose immune systems are depressed. They can be more susceptible to infection by certain pathogenic bacteria, such as E. coli O157:H7 and Listeria monocytogenes. Because babies constitute a sensitive group, fruits and vegeta-bles produced for the manufacture of baby foods may be more tightly specified than for other purposes.
6.6.4 Stage 4: Construct a flow diagram
Describing a food product and identifying its intended use generates information that serves in the identification of hazards associated with the materials used to make the product and with characteristics of the product. Many aspects of the production process may also have the potential to give rise to hazards and it should, therefore, be analysed to ensure the identification of possible hazards.
A flow diagram of the production process (Fig. 6.1) should be prepared which identifies the inputs to, and the outputs from, the process, as well as the operating conditions and parameters required to produce the product. Inputs include seed, seed treatment agents, irrigation water, manure, fertilizers and pesticides, as well as water used in post-harvest, pretreatment operations such as hydrocooling to remove field heat and washing to remove soil and
contami-Field preparation Fertiliser (P+K)
Propagation Seed
Pesticide drench application
Crop establishment
Irrigation water Pesticide
Fertiliser (N) Planting
Harvesting
Trimming
Packing
Waste
Cooling
Chilled storage
Distribution
Retail sale Packaging materials
Fig. 6.1 Example flow diagram for the production of a field salad crop.
nants, and so on. Clearly the product itself is the principal output, but others may be product that has been rejected in grading owing to damage or deterio-ration, or waste botanical material (e.g. from trimming and other preparation processes, soil from washing operations, etc.), all of which, given the right cir-cumstances, could give rise to hazards. The process itself will comprise a sequence of various operations including, for example, seed propagation, field or site preparation, fertilizer applications, planting, growing, irrigation, pesticide applications, harvesting, post-harvest handling and post-harvest pretreat-ments, like cleaning and trimming, as well as storage and transport, any of
which may present certain hazards. The scope of the flow diagram should be constrained by the scope of the HACCP study. It should be logically and sys-tematically structured, and provide sufficient detail to allow the identification of hazards associated with the process without constant reference to additional information.
6.6.5 Stage 5: Confirm the flow diagram
The flow diagram may be prepared by referring to information and data concerning the crop production process and the various operations carried out as part of the process. Sources of information may include specifications or data sheets for seed, fertilizers, pesticides and so on, procedures for site preparation and crop production, procedures for harvesting, post-harvest crop management and post-harvest processing, specifications for packaging and storage. Whatever the sources used in its preparation, the completed flow diagram should be confirmed as a true representation of the production process, not a reflection of a theoretical process which differs from the true process because changes have been made which are undocumented and, possibly, unapproved. Ideally, confir-mation should be made by ‘walking the process’, whereby the flow diagram is compared with what actually happens, as it happens. It may not be practical, however, to observe a complete growing cycle to confirm the diagram, so refer-ence must be made to procedures, records and the experirefer-ence of personnel to confirm accuracy and veracity.
6.6.6 Stage 6: Identify and analyse all potential hazards, assess the risks and identify the preventive measures (HACCP Principle 1) The information gathered about the product and its intended use and the infor-mation contained in the process flow diagram form the basis of the hazard analy-sis stage of the HACCP study, along with any other relevant information, for example literature on the foodborne hazards associated with given fruit and veg-etable products. All of the potential hazards associated with inputs to the crop production process, the process itself, outputs from the process and the product should be listed. Each hazard should then be analysed in turn with regard to its nature and the risk associated with it. Risk is the combination of the severity of the adverse effects of the hazard on the health of the consumer and the likelihood of the hazard occurring. It is not an easy thing to quantify. Attention should be given to establishing the risk associated with hazards, because the results will help to focus the HACCP plan on the hazards most important for ensuring the safety of consumers.
Preventive measures should be identified for every hazard that, by its nature, demands control for reasons of consumer safety and compliance with the law. If a hazard is considered to be such a low risk that it is unlikely ever to occur, it may be justifiable to exclude it from further consideration. A preventive measure is an activity, procedure or feature of a process that either prevents the
occur-rence of a hazard, or eliminates it, or reduces it to an acceptable level. The sources of hazards in crop production and pretreatment are diverse and cannot be com-prehensively considered here. They are dependent on the nature of the crop and specific production processes involved. As already stated, they may be introduced with inputs to the production process, or arise as part of the process, or they may be a consequence of some aspect of an output of the process. Equally, they may arise from the product itself, possibly owing to a condition or characteristic of the product. They may be introduced by people, or be derived from the environ-ment, and they may occur as a consequence of a failure in the general manage-ment of the crop production processes and associated processes. Table 6.1 gives a form suitable for keeping a record of the evaluation of hazards.
6.6.7 Stage 7: Determine the critical control points (CCPs) (HACCP Principle 2)
A critical control point (CCP) is ‘A step at which control can be applied and is essential to prevent or eliminate a food safety hazard or reduce it to an accept-able level’ (CCFH, 1997). Preventive measures are applied at CCPs. For every hazard identified in the hazard analysis stage (Stage 6) each step in the process must be assessed to determine if the step constitutes a CCP. Experience and judge-ment can be used to decide whether a process step is a CCP, but reference is often made to the CCP decision tree (Fig. 6.2). Answering each of the four questions in the CCP decision tree provides an invaluable aid to the identification and clarification of CCPs. For instance, the moisture in fruit is not a hazard, as mois-ture represents no harm to consumers. The presence of moismois-ture can allow mould growth and the development of mycotoxins which are potentially hazardous, for example patulin resulting from the growth of Aspergillus clavatus, sometimes found in apple juice. Selecting good quality apples, which are not bruised or damaged, for processing into fruit juice and maintaining them in the right con-dition under appropriate storage, is necessary to prevent mould growth and the formation of mycotoxins. Product selection (a YES response to question 2) and product storage (a NO response to question 4) each represent CCPs in this instance.
Care must be taken not to create more CCPs than are needed to ensure food safety as the complexity and costs of maintaining the HACCP system will increase unnecessarily. It can be argued that the possible hazard of excessive pesticide residues on fruit and vegetables may need control through different preventive measures concerning, for example, operator training, use of the correct pesticide, application of pesticide at the advised concentration and rate, and the maintenance and calibration of spraying equipment. Of these different areas of apparent control, application at the advised concentration and rate can be defined as a CCP. Training operators, using the correct pesticide and main-taining and calibrating spraying equipment are all activities that should be dealt with under GAP. The identification of CCPs can be recorded with details of hazards in Table 6.1.
Fruit and vegetable processing Table 6.1 Worksheet for hazard analysis and CCP identification
Process Hazard Control Q1* Q2 Q3 Q4 CCP Justification for
step measures Yes/No being a CCP
*See Fig. 6.2
6.6.8 Stage 8: Establish critical limits for each CCP (HACCP Principle 3) A critical limit is ‘A criterion which separates acceptability from unacceptability’
(CCFH, 1997). Critical limits establish parameters for the operation of preventive measures at CCPs and often concern quantitative values such as time, tempera-ture, pH, aw, concentration, application rates and so on. Critical limits may be set by regulations (e.g. pesticide MRLs defined by law), they may be recommended
Q1. Do preventive measure(s) exist for the identified hazard?
YES NO Modify step, process or product
Is control at this step necessary for safety? YES
NO NOT a CCP STOP*
Q2. Does this step eliminate or reduce the likely occurrence of a hazard to an acceptable level?
NO YES
Q3. Could contamination with identified hazard(s) occur in excess of acceptable level(s) or could these increase to unacceptable level(s)?
YES NO NOT a CCP STOP*
Q4. Will a subsequent step eliminate identified hazard(s) or reduce the likely occurrence to an acceptable level?
CRITICAL CONTROL POINT NO
YES NOT a CCP STOP*
*Proceed to next step in the described process
Fig. 6.2 CCP decision tree. Note that for each hazard identified, each question should be answered in relation to each step of the production process. Source: FLAIR, undated.
HACCP User Guide, Concerted Action no 7, Food Linked Agro Industrial Research, 191, Rue de Vaugirard – 75015, Paris.
by industry codes of practice, or, for example, be established by manufacturers of proprietary agents and growers or customers, by reference to scientifically accepted values. Provided the critical limits established for a CCP are being adhered to, product safety with respect to the CCP should be assured. In some instances operational limits for some elements of crop production processes may be set with reduced tolerances compared to the critical limits of CCPs to provide a safety margin for the management of CCPs. Records of the control activities at CCPs should be maintained for HACCP system verification and maintenance, as well as to provide evidence of due diligence in the production of safe food.
6.6.9 Stage 9: Establish a monitoring system for each CCP (HACCP Principle 4)
Monitoring activities are carried out to confirm that the controls exercised at CCPs remain effective to ensure food safety. CCPs are monitored and the mon-itoring activities or procedures must be capable of detecting that control has been lost. Monitoring generally consists of a planned sequence of observations or mea-surements and the results of monitoring are essential to show that the HACCP system is operating effectively. Monitoring methods should be as simple as pos-sible and may concern various forms of measurement, such as temperature, time, concentrations, pH and so on, or they may be based on the observation of pro-cedures and the checking of records. The HACCP plan should identify how each CCP is to be monitored, the frequency of monitoring and who is responsible for ensuring that monitoring is carried out. Records of monitoring activities should be maintained for HACCP system verification and maintenance, as well as for due diligence purposes. Although conventionally, monitoring activities show that control has been lost at CCPs, it can be beneficial to use monitoring, when pos-sible, to indicate that a CCP is going out of control. Rather than allow control to be lost and then have to take corrective action to remedy the problem, it makes sense to adopt a preventive position to ensure control is maintained, as far as pos-sible, at all times.
6.6.10 Stage 10: Establish corrective action procedures (HACCP Principle 5)
In the event that monitoring shows that a CCP is no longer in control, corrective action must be taken, (a) to return the CCP to a state of control and (b) to iden-tify and manage any potentially non-conforming (unsafe) product. A corrective action procedure should be established for each CCP identifying a specific course of action for the return of control. It should also define requirements for identi-fying, segregating and testing implicated product, as appropriate, to prevent non-conforming product being inadvertently despatched to customers. Each corrective action procedure should identify the personnel responsible for taking action and controlling product, as well as the personnel responsible for verifying that control has been returned. The corrective action procedures constitute the corrective action plan for the HACCP system.