The following points highlight top seven stages of HACCP scheme. The stages are:- 1. Hazard Analysis 2. Identification of Critical Control Points (CCPs) 3. Establishment of CCP Criteria 4. Monitoring Procedures for CCPs 5. Protocols for CCP Deviations 6. Record Keeping 7. Verification.
Stage # 1. Hazard Analysis:
In the first stage, the HACCP team produces a full description of the product and its intended use and conducts a detailed evaluation of the entire process to produce a flow diagram.
This must cover all process steps under the manufacturer’s control but may also extend beyond this, from before the raw materials enter the plant to the product’s eventual consumption. If the eventual consumers include a high proportion of a particularly vulnerable group of the population such as infants, the elderly or sick this too should be identified.
The flow chart must contain details of all raw materials, all processing, holding and packaging stages, a complete time-temperature history, and details of factors such as pH and aw that will influence microbial growth and survival.
Additional information covering plant layout, design and capacity of process equipment and storage facilities, cleaning and sanitation procedures will also be necessary to assess the possible risks of contamination. Once completed, it is important that the accuracy of the final document is verified in a separate assessment during which the process is inspected using the flow diagram as a guide.
Hazard analysis should determine where hazards might arise by identifying:
(i) raw materials or ingredients that may contain micro-organisms or metabolites of concern;
(ii) the potential for contamination at different stages in processing;
(iii) intermediates and products whose physical and chemical characteristics permit microbial growth and/or survival; and,
(iv) measures that will control hazards such as process steps that are lethal or bacteriostatic.
Stage # 2. Identification of Critical Control Points (CCPs):
Once the hazard analysis has produced a list of the potential hazards, where they could occur, and measures that would control them, critical control points (CCPs) are identified.
A CCP is defined as a location, step or procedure at which some degree of control can be exercised over a microbial hazard; that is, the hazard can be either prevented, eliminated, or reduced to acceptable levels. Loss of control at a CCP would result in an unacceptable risk to the consumer or product.
A raw material could be a CCP if it is likely to contain a microbial hazard and subsequent processing, including correct consumer use, will not guarantee its control.
Specific processing steps such as cooking, chilling, freezing, or some feature of formulation may be CCPs, as could aspects of plant layout, cleaning and disinfection procedures, or employee hygiene. Many are self-evident, but decision trees can be used to help in their identification (Figure 11.10).
On reflection, it is clear that the extent to which hazards are controlled by different CCPs will differ; heat processing will kill micro-organisms and can, potentially, assure safety, while chilling arrests the growth of most pathogens but will not eliminate them.
The ICMSF has tried to deal with this problem by defining two types of CCP: a CCP1 assures control of a hazard, while a CCP2 minimizes but cannot assure control of a hazard. This approach has been criticized on the grounds that control of a CCP1 could be taken to imply an absolute guarantee of hazard control whereas it simply minimizes a risk with a higher level of assurance than a CCP2.
For example, the heat process in producing a low-acid canned food is clearly a very important CCP but its successful control does not guarantee control of hazards if the cans are cooled in contaminated water and some have faulty seams. Indeed, in this case, the evidence is that post-process contamination is the principal cause of failure in food canning.
Stage # 3. Establishment of CCP Criteria:
For each of the CCPs identified, criteria must be specified that will indicate that the process is under control at that point. These will usually take the form of critical limits (with tolerances where appropriate) necessary to achieve control of the hazard.
Criteria may include:
(i) physical parameters such as temperature/time, humidity, quantity of product in a pack, dimensions of can seams, or depth of product in trays to be chilled;
(ii) chemical parameters such as pH in fermented or acidified foods, aw in intermediate-moisture foods, salt concentration, available chlorine in can cooling water, or level of preservative;
(iii) sensory information such as texture, appearance, or odour; or,
(iv) management factors such as the correct labelling of products with instructions for use and handling, or efficient stock rotation.
Stage # 4. Monitoring Procedures for CCPs:
Crucial to the application of criteria at CCPs is the introduction of monitoring procedures to confirm and record that control is maintained. It is important to remember that the assurance given by monitoring procedures will only be as good as the methods used and these too must be regularly tested and calibrated.
To achieve the on-line control of a processing operation, monitoring procedures should wherever possible be continuous and give ‘real time’ measurement of the status of a CCP. In some cases, the availability of appropriate monitoring procedures could govern the choice of criteria.
If continuous monitoring is not possible then it should be of a frequency sufficient to guarantee detection of deviations from critical limits, and those limits should be set taking into account the errors involved in periodic sampling.
The long elapsed times involved in obtaining microbiological data means that microbiological criteria are not generally used for routine monitoring of CCPs, other than perhaps the testing of incoming raw materials. Microbiological testing does however play an important part in verification.
Records should be kept of the performance of CCPs. These will assist in process verification and can also be analysed for trends which could lead to a loss of process control in the future. Early recognition of such a trend would allow pre-emptive remedial action to be taken.
Stage # 5. Protocols for CCP Deviations:
When routine monitoring indicates that a CCP is out of control there should be clearly described procedures for its restoration, who is responsible for taking action and for recording the action taken. In addition to measures to restore the process, it should also prescribe what should be done with product produced while the CCP was out of control.
Stage # 6. Record Keeping:
The HACCP scheme should be fully documented and kept on file. Documentation should include details of the HACCP team and their responsibilities; material from the Hazard Analysis such as the product description and process flow diagram; details of the CCPs – the hazards associated with them and critical limits; monitoring systems and corrective action; procedures for record keeping and for verification of the HACCP system.
This should be accompanied by associated process records obtained during operation of the scheme. It will also include material such as documentation to verify suppliers’ compliance with the processor’s requirements, records from all monitored CCPs, validation records and employee training records.
Stage # 7. Verification:
Verification is the process of checking that a HACCP system is working effectively. It is an essential feature of quality control based on HACCP and is used both when a system is first introduced and to review existing systems. Verification uses supplementary information to that gathered in the normal operation of the system and this can include extensive microbiological testing.
To verify that criteria or critical limits applied at CCPs are satisfactory will often require microbiological and other, more searching, forms of testing. For example, microbial levels may need to be determined on equipment where day-to-day monitoring of cleaning procedures is based on visual inspection alone, or the precise lethality of a prescribed heat process may have to be measured.
In normal operation, only limited end product testing is required because of the safeguards built into the process itself, but more detailed qualitative and quantitative microbiological analyses of final product and product-in-process may be required in a verification programme. Supplementary testing must be accompanied by a detailed on-site review of the original HACCP plan and the processing records.
One of the great strengths of the HACCP approach is its specificity to individual production facilities. Differences in layout, equipment and/or ingredients between plants producing the same product could mean that different CCPs are identified. Similarly, small changes in any aspect of the same production process could lead to verification identifying new CCPs or weaknesses in existing criteria or monitoring procedures.
Because of its highly specific and detailed nature, it is not possible to present here a full HACCP system for particular food products. But by way of illustration, Figure 11.11 shows the flow diagram of a process for the production of a yoghurt flavoured by the addition of fruit or nut puree with critical control points identified.
Here the microbiological safety hazards are the presence of pathogens or their toxins. The final product has a pH of 3.9-4.2 and, stored at chill temperatures, it will not permit pathogen growth and will in fact have a moderate lethal effect depending on the pathogen considered. The properties of the product will however have no effect on pre-formed toxins introduced during processing.
Control of pathogens in the product is obtained by pasteurization of the milk and by ensuring a satisfactory fermentation to give pH < 4.3 so CCPs will be located at points critical to achieving these goals.
For example, incoming milk must be tested for antibiotic residues which may inhibit starter-culture activity, and the time and temperature of heat treatment, and factors governing the fermentation such as temperature and starter composition, must all be strictly controlled and monitored.
The possibility that the fruit or nut puree may contain pre-formed toxins is a matter which is under the control of the supplier. The pH of the fruit puree is likely to control any possibility of growth and toxin production by bacterial pathogens, although mycotoxins might be a concern.
To control yeasts which could reduce the product’s shelf-life, it may be necessary to specify the heat process given to the fruit puree and to store it at chill temperatures prior to use. Nut puree requires more stringent control because of its higher pH. The supplier should provide evidence that it has received a botulinum cook and that the nuts used in its preparation were of good quality and free from aflatoxin.
The US Department of Agriculture has produced a generic HACCP analysis of the production of raw beef. Such documents can provide a useful guide to a HACCP team but care must be taken that unique factors applying to the operation under study are not overlooked.