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Whilst the HACCP principles and concepts of farm-to-fork in risk assessments are clearly developed to ensure food safety, the approach and thinking can easily be applied to cover other quality aspects, such as sensory quality, composition or labeling, as well. Instead of identifying the hazards of the process / product, potential defects are considered. The steps or points at which control of the defects are to be controlled are called defect action points (DAPs) (CAC, 2002) as a parallel to the critical control points (CCPs) where hazards can be controlled. Similar to the procedures for CCPs, limits, monitoring procedures, corrective actions and verification procedures must be established at the DAPs.


A condition found in a product which fails to meet essential quality, composition and/or labelling provisions of the appropriate standards or specifications (NOAA, 2000)

Defect Action Point (DAP)

A point, step or procedure at which control can be applied and a defect can be prevented, eliminated or reduced to acceptable level, or a fraud risk eliminated (NOAA, 2000)

The analysis of potential defects and identification of DAPs follows the same procedures as when conducting a hazard analysis. For instance, the decision tree used to determine if a point is really a critical control point, can be used equally well to decide if a given point is a DAP.

Defects may, as hazards, be of (micro) biological, chemical or physical nature. The substitution of one (lower value) fish species for another (high value) is an example of a biological defect, fraud. Similarly, raw materials for production of semi-preserved herring must have specific lipid content for the right ripening and texture to develop. Therefore lower or higher lipid content is a biological defect. This should be monitored on the incoming raw material and batches with wrong lipid content should be used for other products.

Other kinds of defects include incorrect weight or incorrect labelling.

10.1 Microbiological aspects

This book has so far focused on the risk to consumer health arising from the presence and growth of microorganisms. However, microorganisms may have other adverse effects on the quality of fish and fish products. Thus growth and activity of microorganisms is the major cause of decomposition (spoilage) of all types of products where microorganisms have not been completely eliminated (such as in canned foods) or where growth of microorganisms has not been completely arrested (such as in frozen foods). A description of the spoilage patterns of different fish products and the microorganisms involved can be found in Huss (1995), Gram and Huss (2000) and Gram et al. (2002).

It has been estimated that between 10 and 50% of all foods produced are lost post harvest or post slaughter due to microbial activity (Kaferstein and Moy, 1993; cf Baird-Parker, 2000; WHO, 1995). Decomposition or presence of filth is the most common cause of detention of fish products imported into the US (FDA, 2002). Thus, out of 4,527 detentions in April, May and June 2002, 443 of the detained products were fish or seafood products. Of the 443 detentions, half (213) were detained because of filth and/or spoilage (FDA, 2002).

In principle control of decomposition of fish and fish products is simple since low temperature will retard all spoilage processes. In contrast, just a few hours exposure to high temperatures may accelerate spoilage. In some tropical countries, icing is not done on board the fishing boats and this leads to rapid reduction in eating quality (Figure 10.1). It also follows indirectly from the figure that temperature during storage is critical. Loss of quality occurs rapidly.

Figure 10.1
Quality changes in iced Nile perch, iced immediately after trawl-catch (n) or with 3, 6, 9 or 12 hours delay in icing (Gram, 1989).

Therefore control of the time x temperature chain is critical. This DAP applies to all steps from catch, through processing and distribution to the consumer. Several initiatives are on the way, where different tags will allow monitoring of the accumulated time x temperature, however, none are used commercially in the fish industry. To date, the most efficient and reliable way of determining whether or not this DAP is under control is sensory evaluation.

Monitoring of time x temperature during handling and processing can be done by date marking of boxes and containers and by visual inspection of icing and chilling conditions. Time and temperature recording at specific points and during processing should preferably be controlled automatically. Process flow must be designed to avoid stops and interruptions, and chill rooms must be supplied with thermometers. Visual inspection (e.g. quantity of ice) and control checks of temperature must be done in a daily routine. A log of temperature recordings (manually or automatically read) must be kept and be available at all times.

Off-flavour may also arise in fish due to microbial growth that is not related to spoilage aspects. The muddy flavour often detected in fresh water fish such as trout is caused by the compound geosmin. Blue-green-algae, actinomycetes and cyanobacteria are capable of producing geosmin. The compound accumulates in the fish flesh and is not toxic to fish nor humans. Again, sensory evaluation is the most reliable detection technique. Allowing the fish to swim in clean water for 4-7 days can reduce (purge) the off-flavour.

10.2 Chemical aspects

Chemical defects refer to quality deterioration due to chemical reactions. Very common are the changes which may occur in the fish lipid fraction. This may be either oxidation or hydrolysis. Both reactions result in the production of substances with unpleasant - rancid - off-flavours. Other changes such as dehydration and autolysis may lead to poor texture and freeze burns. During frozen storage, especially of gadoid fish species, trimethylamine oxide (TMAO) is reduced to dimethylamine (DMA) and formaldehyde (FA). This adds to the changes in texture and flavour occurring during frozen storage.

Availability of oxygen (or other oxidizing compounds) is required for oxidative rancidity to develop and non-oxygen containing packaging of fatty fish species will control this defect. As with microbial reactions, temperature is important. Thus, the development of free fatty acids in herring is greatly accelerated at 12°C as compared to 0°C (Figure 10.2)

Figure 10.2
Development of free fatty acids in herring stored at different temperatures (redrawn from Huss 1995).

Any contamination occurring during processing - which is not included as a hazard in the HACCP plan - will also constitute a defect. This could be (re)contamination by cleaning agents, by mechanical grease or by using wrong ingredients. During canning of foods, metals may leak from the cans and contaminate the product.

10.3 Physical aspects

Defects of physical nature cover a range of aspects such as the presence of small bones, foreign matter (e.g. hairs, straw) or material which should not be there (scales, pieces of skin etc.). Other physical defects can damage the packaging causing bruising or change of carton shape.

10.4 Example

CAC (2002) provides a good example of the use of defect analysis and identification of DAPs (Tables 10.1, 10.2 and 10.3). As with the hazard-analysis, the production flow must first be outlined (Figure 10.3).

Figure 10.3 Example of a flow diagram for a processing line of canned tuna fish in brine (CAC, 2002).

The defect analysis identifies several possible defects (Table 10.1).

Table 10.1 An example of potential defects of canned tuna (modified from CAC, 2002).

Defect type

In raw tuna

During processing, storage or transportation



spoilage, survival and growth of spoilage microorganisms





objectional matter (viscera, scales, skin...), formation of struvite crystals, container defects


species substitution

abnormal flavours, incorrect weight, incorrect coding, incorrect labelling

Spoilage is as outlined mainly a problem of time x temperature control of the non-frozen or non-canned fish. Further analysis points to the development of rancid off-odours as a potential defect. Each processing step should then be considered to determine if it is a possible action point for the defect. Table 10.2 illustrates the preliminary analysis of step two in the fish flow, i.e. the frozen storage step. Since the frozen tuna are often stored in bulk, the frozen storage period could be a potential DAP.

Table 10.2 An example of the significant defect rancidity during the storage of frozen tuna for canning tuna (modified from CAC, 2002).

Processing step

Potential defect

Is the potential defect significant


Control measures

Storage of frozen tuna

persistent and distinct rancid odours and flavours


product does not meet quality or customer requirements

· glazing
· controlled temperature in the storage premises
· packaging
· stock management procedure
· maintenance of procedure of the refrigeration system
· personnel training and qualifications

The analysis indicates that the frozen storage could be a DAP for development of rancid off-odours. A more detailed analysis - similar to the decision tree for critical control points - is presented in Table 10.3.

Table 10.3 A schematic example of a defect analysis with corresponding control measures and the application of the Codex decision tree for the determination of a defect action point during storage of frozen tuna (CAC, 2002). Q = question; A = answer.

Q1: Do control measures exist?

If yes - go to Q2

If no - consider whether control measures are available or necessary within the process

proceed to next identified defect

Q2: Is the step specifically designed to eliminate or reduce the likely occurrence of rancidity to an acceptable level?

If yes - this step is a DAP

If no - go to Q3

Q3: Could rancidity occur in excess of acceptable levels or could it increase to unacceptable levels

If yes - go to Q4

If no - not a DAP

Q4: Will a subsequent step eliminate rancidity or reduce its likely occurrence to an acceptable level?

If yes - not a DAP

If no - DAP

A: Yes, the storage temperature is controlled, procedures exist

A: No

A: Yes, if the storage time is too long and/or the storage temperature is too high or if packaging is broken or unsuitable, or if glacing is inadequate

A: No

Decision: storage of frozen tuna is a defect action point


Baird-Parker, T.C. 2000. The production of microbiologically safe and stable foods. In: Lund, B.M., T.C. Baird-Parker and G.W. Gould (eds.) The Microbiological Safety and Quality of Foods. Aspen Publishers Inc., Gaitherburg, Maryland, USA. pp.3-18.

CAC (Codex Alimentarius Commission) 2002. Draft Code of Practice for Fish and Fishery Products. Alinorm 03/18. Food and Agriculture Organization / World Health Organization, Rome, Italy.

FDA (Food and Drug Administration) 2002. Import refusal reports for OASIS

Gram, L. 1989. Isolation, identification and characterization of bacteria isolated from tropical fish. Ph.D. thesis. The Technological Laboratory of the Danish Ministry for Fisheries and The Royal Veterinary and Agricultural University, Denmark.

Gram, L. and H.H. Huss 2000. Fresh and processed fish and shellfish. In: Lund, B.M., T.C. Baird-Parker and G.W. Gould (eds.) The Microbiological Safety and Quality of Foods. Aspen Publishers Inc., Gaitherburg, Maryland, USA. pp. 472-506.

Gram, L., L. Ravn, M. Rasch, J. B. Bruhn, A.B. Christensen and M. Givskov 2002. Food spoilage - interactions between food spoilage bacteria. International Journal of Food Microbiology 78, 79-97.

Huss, H.H. (eds) 1995. Quality and Quality Changes in Fresh Fish. FAO Fisheries technical paper No. 348., FAO, Rome, Italy.

Kaferstein, F.K. and G. Moy 1993. Public health aspects of food irradiation. Journal of Public Health Policy 3, 502-510.

NOAA (National Oceanic and Atmospheric Administration) 2000. NOAA HACCP Quality Management Program. Program Requirements. National Marine Fisheries Service, Seafood Inspection Program, Maryland, USA.

WHO (World Health Organization) 1995. Food Safety Issues: Food Technologies and Public Health. WHO/FNA/FOS 95.13. WHO, Geneva.

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