Post-mortem Meat Inspection

6 Post-mortem Meat Inspection


6.1 Meat Inspection – General Principles


The purpose of meat inspection is to certify whether or not meat is fit for human consumption. There are no clearly written guidelines covering all situations; instead, the Official Veterinary Surgeon (OVS) has overall responsibility for the decision. In the UK, meat inspection is normally conducted by meat hygiene inspectors, who do not have a university qualification, but do have up to 2 years’ formal training in higher education. Meat inspectors are supervised by the OVS or veterinarian in the plant. Meat inspectors conduct routine, technical inspection, and can approve any meat which appears to have no abnormalities. For more unclear or difficult cases, however, the responsibility passes to the OVS. This is a great responsibility with both ethical and legal implications, and with serious consequences. Therefore, each OVS must feel satisfied with own decision, and be ready for further consultation, as necessary.


Meat inspection must be conducted systematically. In the case of inspection at abattoirs, the system is normally well set up, but in other situations (e.g. on-farm), there may be no normal inspection system operating. For example, if any organs are not available for inspection, the carcass cannot be inspected thoroughly, and the meat must not be passed for human consumption. Incorrect inspection and approval of unfit meat could have extremely serious consequences for a number of people purchasing and/or consuming the product.


The technical procedures for post-mortem inspection were set up around 150 years ago, and have not changed substantially since then. The basic steps include:


1. Visual examination of the whole carcass and all organs should always be conducted first, because the inspector should not endanger his/her own health or that of other people by unnecessary handling of an animal with obvious signs of a transmissible disease. Visual inspection implies that the inspector is familiar with the normal appearance of tissues and organs, so that abnormalities can be assessed; the focus is on the size, shape and colour.


2. Palpation of the organs is routinely used, as specified for different organs/tissues in different species, to get a feeling of the ‘texture’ of the tissue: stickiness, softness, dryness, wetness, etc. Palpation is useful for organs or tissues with conditions that do not always produce a visible difference, e.g. arthritis.


3. Incision of organs/tissues is routinely used, but not for all organs and tissues.


4. Any additional examinations are conducted when the meat inspector or OVS considers it necessary, including taking samples for rapid (on-site) laboratory tests if needed. Further investigation is needed when any abnormalities are found, to assess their nature and extent. At this stage, incisions may be applied more extensively, to obtain the necessary information, and samples may be taken for laboratory investigation as necessary. Further investigation, over that required for routine inspection, can be costly, but this is a secondary consideration when extra assurance for protection of public health is required.


During post-mortem inspection, it is often necessary to determine whether the slaughtered animal is female or male, because some diseases are sex-linked, appearance of organs/tissues can differ between sexes, and overall size/condition of the carcass can vary with the sex. The main parameters used for sex determination on carcasses are indicated in Table 6.1.


Understandably, not every single part of the tissues/organs in the animal can be inspected for signs of abnormalities in great detail, so examination of the state of the lymph nodes may help to determine the status of the correlated body parts. The lymph node is assumed to be an indicator of the existence of pathological processes in the region from which it drains lymph; its status indicates whether there is a need to inspect the related organ/tissue directly and in greater detail. The lymph node, while reacting to harmful or infectious agents, may change appearance: become enlarged, have haemorrhages, abscesses, etc. Obviously, to use the information obtained from lymph node inspection, the inspector must be familiar with the anatomical location and physiological role of individual lymph nodes, the area from where each lymph node drains the lymph fluid and the flow of the lymph between lymph nodes (see Figs 6.1 and 6.2).


Using basic inspection techniques described above, carcasses and offal (and blood where appropriate) of all animal species are routinely examined for:


• sex and age;


• state of nutrition;


• local/general oedema;


• efficacy of bleeding;


• swelling/deformity;


• abnormal colour, odour or taste;


• condition of pleura and peritoneum;


• any other abnormality; and


• signs of specific diseases.


Table 6.1. Sex determinants in carcasses post-slaughter.


image

image

Fig. 6.1. Lymphatic system in cattle (proximal body): downward flow.


image

Fig. 6.2. Lymphatic system in cattle (caudal body): upward flow.


Further Reading

Wilson, A. and Wilson, W. (1998) Practical Meat Inspection. Blackwell, Oxford, UK.



6.2 Meat Inspection of Main Animal Species


Introduction

The currently used, routine post-mortem inspection of the main red meat animal species can be best illustrated by using the example of cattle, which is probably the most complex species from the inspection perspective. Subsequently, main comparable differences in other species can be highlighted.


Meat Inspection of Bovines >6 Months

Inspection of carcass

• Examination of the carcass visually, looking at all surfaces from all angles;


• determination of the sex of the carcass;


• examination of the joints for arthritis;


• examination of the colour of fatty and muscle tissues (both should be within the normal range) – fatty tissue yellowing can be caused by abnormal liver function, by normal ageing of the animal or by the type of feed consumed;


• examination of muscle tissue for bruising;


• inspection of visible blood vessels with care: these must be properly drained of blood;


• inspection of the abdominal cavity for signs of adherence (peritonitis);


• inspection of the thoracic cavity for signs of pleurisy or tuberculous lesions; and


• if the carcass is considered to be normal, based on the above examination, further cutting will not be required.


Inspection of kidneys

Kidneys normally remain attached to the carcass for inspection, which is conducted by visual inspection and palpation. Only if any abnormality is detected should the renal lymph nodes be cut open to detect nephritis.


Inspection of head

Visual inspection of the head from all angles. Technically, the following should be visually examined, followed by additional examination where indicated:


• mandibles for irregular shape, e.g. in the case of actinobacillosis;


• eyes for abnormal appearance or colour, e.g. yellowing caused by icterus;


• tongue for abnormal lesions, e.g. symptomatic of foot and mouth disease, and by palpation for deeper abnormalities (e.g. actinobacillosis, cysticercosis);


• incisor teeth for age; if >24 months, must be tested for BSE;


• lymph nodes, each of which exist in pairs: retropharangeal, submandibular, parotid (note: tuberculosis can be diagnosed in these lymph nodes); and


• cheek muscles: external cheek muscles are incised with two parallel cuts, and internal cheek muscles with one, to inspect for T. saginata cystercircus.


Inspection of lungs

• Visual inspection for pneumonia, cysts (e.g. hydatid), abscesses, tumours, etc.;


• palpation to detect any of the above within deeper tissue;


• incision and examination of bronchial, mediastinal pairs of lymph nodes (note: tuberculosis can be diagnosed in these lymph nodes); and


• incision to open trachea and lower airways to examine for inflammation and foreign contents (food, parasites, blood, etc.) or partially swallowed food.


Inspection of heart

• Visual inspection for pericarditis;


• opening of pericardial sac to examine for abnormal amount or appearance of the liquid; and


• incisions to open all chambers to examine for endocarditis, and for cysticercosis cysts in the septum.


Inspection of diaphragm

If cysticercosis has been found in the cheek muscles or in the heart, the diaphragm must also be inspected.


Inspection of liver

This organ is particularly important as a general indicator of animal health, as many abnormalities occur in the liver of sick animals:


• visual examination for degenerations, dystrophies, cysts (e.g. hydatid), abscesses, tumours, tuberculous lesions;


• palpation to detect any of the above in deeper tissue, palpation of the hepatic lymph node (and its incision if any abnormalities found); and


• incisions to open the bile ducts (along the main ducts and across the caudal lobe) to examine for liver fluke infestation.


Inspection of spleen

The spleen may be separated from, or attached to, rumen, and is examined by visual inspection and palpation for changes in colour, size (edges are normally sharp) and consistency. Splenic enlargement and/or dark colour is commonly associated with infective diseases (e.g. anthrax) and septicaemia. Note that splenic colour can differ between sexes.


Inspection of alimentary tract

Alimentary tract contents are usually inspected whilst placed in trays, and include oesophagus, rumen and large and small intestines:


• visual inspection of rumen and intestines for enteritis, etc.: salmonellosis and Johnes’ disease both cause redness of the enteric tract, so may be detected by visual inspection;


• palpation of the mesenteric lymph nodes – if any abnormality is detected, these lymph nodes may be incised for further inspection; and


• palpation of oesophagus for parasitic cysts, etc.


Genital organs

These are visually inspected and palpated; they are incised only if any abnormality is detected.


Udder

The udder is examined, visually and by palpation, after it has been separated from the carcass. Although a thick fat layer may remain after udder removal, this does not indicate abnormality. Conduct a visual inspection and palpation. Mastitis is frequently caused by zoonotic agents, so care must be taken to avoid milk secretion and spillage, with possible contamination of other edible tissues. Also, tuberculous lesions may be found in the udder.


Meat Inspection of Bovines <6 Months

These young animals are inspected in a manner similar to that for adult bovine animals, with the following differences:


• cheek muscles are not incised to examine for T. saginata cysticercus, as the animals are considered too young to be infected with infective larvae;


• attention should be paid during inspection of the umbilical region and joints, as abnormal findings (e.g. arthritis) can be associated with salmonellosis; and


• the liver is not incised for detection of liver fluke, as these animals are considered too young for this parasite to occur.


Meat Inspection of Other Red Meat Species

Horses (solipeds), sheep/goats, pigs and farmed game are inspected in a manner similar to that for adult bovine animals, with the following differences:


Horses (solipeds)

• Head: the mucous membranes and nasal cavities/sinuses/septum are inspected after the head has been split along the median line for glanders; visual examination and palpation of other parts and incisions only if necessary;


• liver: visually inspected and palpated; incised only if necessary;


• udder: visually inspected and palpated; incised only if necessary;


• all grey horses must be examined for melanosis and melatomata, since their light pigmentation predisposes them to skin and other cancers: the attachment of one shoulder is loosened and muscles and prescapular lymph node are inspected;


• kidneys: visual examination and incision; and


• muscles: inspection for Trichinella spiralis (see Chapter 6.4).


Farmed deer and game

Farmed deer have similar diseases to those occurring in cattle. Therefore, inspection procedures are practically the same as those described for bovines >6 months.


Sheep/goats

Mandatory, routine inspection of sheep and goats is conducted in a manner as for bovines >6 months, except that inspection is based on visual examination and palpation. The only mandatory incision is for the hepatic bile ducts, to detect the presence of liver fluke, but other incisions can be made if necessary, i.e. in case of detected abnormalities.


Pigs

Mandatory, routine inspection of pigs is conducted in a manner as for bovines >6 months, except for:


• careful visual inspection of skin for diseases (e.g. erysipelas, swine fever) or tail biting;


• careful incision and inspection of submaxillary lymph nodes for tuberculous lesions;


• bile ducts in liver are not incised unless necessary; and


• muscle samples from the root of the diaphragm (where it is attached to the vertebral column – Crura diaphragmatis) are inspected for Trichinella infection (see Chapter 6.4).


Mandatory Provisions Where Tuberculosis is Suspected – All Species

If tuberculosis infection of an animal is suspected because of either the results of routine tuberculin testing (i.e. reactors), the epidemiological data or of the findings at ante- or post-mortem inspection, further in-depth inspection must be conducted including:


• carcass must be split and vertebrae, ribs, sternum, spinal cord and brain (where needed) are examined;


• incision and examination in detail of all major lymph nodes on the carcass and organs. The lymph nodes which are least likely to be infected must be examined first, to reduce the risk of cross-contamination; and


• careful sanitation of all knives, gloves, aprons, etc. between different areas of the carcass.


Further Reading

Anon. (2004a) Good Practices for Meat Industry. FAO Animal Production and Health Manual, FAO, Rome.


Anon. (2004b) Meat Hygiene Service: Operational Manual (Vols 1 and 2). The UK Food Standard Agency, Meat Hygiene Service, London


Gracey, J., Collins, D.S. and Huey, R. (1999) Meat Hygiene. W.B. Saunders Company Ltd, London.


Wilson, A. and Wilson, W. (1998) Practical Meat Inspection. Blackwell, Oxford, UK.



6.3 Meat Inspection – Judgement of Fitness


Deciding on fitness of meat for human consumption is a complex and serious activity, with numerous and various implications of public health; some have implications of a legal, ethical or commercial nature. The Official Veterinary Surgeon should make related decisions only when he/she is confident that the information obtained is sufficient for an appropriate decision; otherwise, he/she should seek more information (e.g. further examinations, laboratory tests, expert opinions, etc.). During the process, the Official Veterinary Surgeon should not be put, or feel, under undue pressure from interested parties.


The Judgement Process

The decision-making process should be systematic; the following questions will help to address the question of fitness of the inspected meat:


• Is there any aspect from the Food Chain Information (FCI) system relevant for the meat fitness?


• Is there any aspect from the ante-mortem inspection relevant for the meat fitness (see Fig. 6.3).


• Can diseased or abnormal tissues, if found, be removed and condemned, leaving safe, edible tissues?


• Is the condition localized or generalized; is it acute or chronic? Chronic or localized disease lesions can be removed more easily than can acute or generalized lesions?


• Is there derangement of body function?


• Is the condition harmful to human health or to animal health? If the condition affects animal health, the information should be relayed to the farm of origin and/or government agencies; if the condition affects human health, it clearly must be acted on.


• Is the condition aesthetically offensive and repugnant? If yes, it is unfit although it may not represent a health risk.


• Do I feel confident with my own judgement? If not, delay the final decision.


• Is further information required? If yes, obtain help and opinion from senior colleagues, experts and laboratory tests.


image

Fig. 6.3. Decision tree for post-mortem inspection of suspect animals.


Identification of conditions and judgement principles

Removal/condemnation of diseased/abnormal tissue

All abnormal organs/tissues are unfit for human consumption, regardless of the cause. Some common examples include localized abscesses in pig meat, a single hydatid cyst in liver or a bruised chicken limb. The affected parts must be removed and condemned (appropriately disposed of), while the remaining healthy normal tissues can be fit for human consumption.


Localized versus generalized and acute versus chronic

A disease process is localized when the pathological changes are in a limited area and no serious changes exist in other tissues or organs. Acute lesions are often generalized, including septicaemia, pyaemia, pyrexia and toxaemia. Recognition of these conditions requires significant knowledge and practical experience.


Derangement of body function

Derangement of body function occurs when any disease or condition has progressed to the point where an important bodily function is impaired. It affects the general physiology. This condition requires condemnation of the entire carcass, although the primary disease itself is insufficient for condemnation. Examples include obstructive uraemia, icterus, generalized oedema caused by heart failure and emaciation caused by poor teeth. In these cases, the carcass may not represent a risk to human health, but would be unacceptable to consumers.


Harmfulness to human health

There are three main categories of conditions which could seriously affect human health. First, transmissible diseases – including those caused by bacteria, viruses, parasites – and BSE are a risk to human health. Second, chemical residues – including industrial pollutants, pesticides and toxins – and residues of medicines can also be deleterious to human health. Third, contamination with food-borne pathogens can lead to development of human alimentary disease.


Offensive or repugnant

Judgement of offensive or repugnant meat is interwoven with all the previous principles. However, it is not always clearly related to public health. Condemnation in these cases is applied because the condition is aesthetically unacceptable (distasteful) to consumers. Examples include stillborn and unborn carcasses, benign tumours, dead parasites, foreign odour and spoilage.


Specific indications rendering whole carcass, offal and blood unfit for human consumption

Current UK legislation enlists the following diseases and conditions, which must result in the declaration of the meat or carcass as unfit for human consumption. Some of these conditions are not zoonotic, but declaring the meat unfit can prevent the product entering the food chain and spreading animal disease further.


Actinobacillosis (generalized) or actinomycosis (generalized)


Anaemia (advanced)


Anthrax


Blackleg


Blood from infectious conditions, or contaminated


Botulism


Brucellosis (acute)


Bruising (severe)


BSE/TSE


Caseous lymphadenitis (generalized)


Cysticercus ovis (generalized)


Decomposition (generalized)


Enteritis


Fever


Foot and mouth disease


Glanders


Jaundice


Lymphadenitis (generalized)


Malignant catarrhal fever


Mastitis (acute septic)


Melanosis (generalized)


Metritis (acute septic)


Odour, abnormal or sexual


Oedema (generalized)


Pericarditis (acute septic)


Peritonitis (acute diffuse septic)


Pleurisy (acute diffuse septic)


Pneumonia (acute septic)


Pyaemia (including joint-ill)


Rabies


Sarcocysts (generalized)


Septicaemia


Stillborn/unborn


Swine erysipelas (acute)


Swine fever


Tetanus


Toxaemia


Trichinellosis


Tuberculosis (generalized or with emaciation)


Tumours, malignant or multiple


Uraemia


Viraemia


Specific judgements for tuberculosis

When tuberculosis (TB) is detected, it must be established whether the condition is generalized (more rare) or localized (more common). There has been very little evidence for meat-borne TB infection in humans (as opposed to milk-borne) over the past 50–100 years, and only evidence appears to relate to consumption of meat from generalized infection cases. Nevertheless, consuming meat from animals which have been infected with TB is largely unappealing to consumers.


When generalized TB is detected, the whole carcass is considered as being unfit for human consumption, and must be condemned. TB is generalized if the disease is found in both lungs and elsewhere in the carcass. Also, the presence of multiple and active lesions, or if the disease is widespread in lymph nodes, indicates generalized TB. Diffuse lesions can occur on both the pleurae and peritoneum. TB is also considered generalized if active lesions are found in any two of the spleen, kidney, udder, uterus, ovary, testicle, brain or digestive tract. Congenital TB in a calf must be considered as generalized.


Localized TB is diagnosed by the presence of lesions in just part of the carcass. The infected part must be declared unfit and condemned, while the remainder of the carcass is considered edible. The head and tongue must be declared unfit if TB is detected in any related lymph node. In this case, if the lesion is inactive and is not enlarged, the lesion may be removed by the OVS, and the head can be declared fit for human consumption.


Specific judgements for BSE and unfit Specified Risk Material (SRM) in ruminants

SRMs specified by legislation are shown in Table 6.2. All SRM must be stained, stored separately from food materials and dispatched to specified licensed premises to be destroyed. Bones and mechanically separated meat are not fit for human consumption.


Specific judgements for some zoonotic parasites

• Trichinellosis (e.g. pigs, horses): unfit (see the diseases list above);


T. saginata cysticersosis (bovines): if few cysts found, they are removed, and the remaining carcass is frozen at −7°C for 3 weeks or at −10°C for 2 weeks to kill any undetected larvae; if infestation is generalized, the carcass is unfit;


T. solium cysticersosis (pigs): unfit;


• liver fluke: the liver is unfit for esthetical reasons, although the disease is not transmited to humans via meat;


• hydatid cysts: the organ is unfit for esthetical reasons, although the disease is not transmited to humans via meat;


• protozoan parasites (e.g. Toxoplasma gondii, Sarcocystis): obviously changed meat is unfit.


Limitations of the conventional (organoleptic) post-mortem inspection and further developments

Post-mortem inspection has been very successful in detecting classic zoonotic diseases that were prevalent at the time of its original development (mid-19th Century), but many of those are now rare or have been eradicated. On the other hand, many new hazards associated with meat have emerged in the meantime. Obviously, the nature of public health problems at post-mortem meat inspection has significantly changed over time, contributing to significant limitations of the conventional meat inspection in modern times.



Table 6.2. Specified risk materials from differing ruminant categories (UK).






















Ruminant category


Specified risk material


Bovines <6 months


Thymus, intestines


Bovines >6 months


Head (excluding tongue), spinal cord, spleen, tonsils, intestines, thymus


Bovines over >24 months; must be tested for BSE


Whole carcass if not tested


Sheep/goats


Head (excluding tongue and horns), spinal cord (>12 months), tonsils, spleen, ileum


Bovines/sheep/goats of all ages


Specified solid waste collected in the drainage system


First, most of the livestock presented at modern abattoirs for slaughter are apparently clinically healthy animals. Traditional meat inspection is of relatively low efficacy in detecting public health hazards amongst this large number of apparently healthy animals. For example, less than 1% of animals show macroscopic lesions, and traditional meat inspection may be detecting only one in five of the lesions actually present in these animals. Also, there are reports that organoleptic meat inspection detects only 10% of bovines actually infected with T. saginata cysticercosis.


Second, the most relevant fresh meat-related public health hazards today are ‘invisible’ i.e. cannot be detected by traditional meat inspection. For example, Escherichia coli O157, Salmonella and Campylobacter are human bacterial pathogens which are typically carried by healthy animals and contaminate meat without any symptoms, but are not detectable by organoleptic post-mortem meat inspection. To make things worse, some techniques of physical examination of meat (palpation, incision) actually spread this microbial contamination within the same carcass or to other carcasses. In addition, chemical residues, including pesticides, toxins, aflatoxins, veterinary medicines and growth promotors represent public health risks that cannot be detected by traditional meat inspection. To address these shortcomings of post-mortem meat inspection, an alternative, in the form of end-product laboratory testing for microbial pathogens, has been advocated. However, end-product testing also has significant disadvantages: it is a reactive (rather than proactive) measure, requiring the product to be stored until the results are obtained; numerous samples are required to produce a statistical representation of the final product; and the testing methods are currently suboptimal and variable, and the testing results relate only to the hazards examined for, but do not guarantee overall safety of the product.


Third, most of the pathological lesions detected by traditional meat inspection are of animal health relevance, but are not necessarily of public health relevance. For example, pneumonia in pigs is caused mostly by microorganisms that cannot cause disease in humans. A second example includes some parasites (e.g. liver fluke, hydatid cysts) which can be detected by traditional meat inspection, but the meat from such carcasses does not represent a public health risk. Clearly, detection of these conditions represents important benefits for animal health (through feedback of the information from abattoirs back to the farms), but in ongoing debates questions arise as to whether these benefits are sufficient to make acceptable the increase of public health risks due to meat cross-contamination generated by these animal disease-detection procedures.


Clearly, the absence of disease symptoms and macroscopic lesions at traditional post-mortem inspection does not mean the absence of microbial or chemical public health hazards in/on meat, but the inspection procedures mediate meat contamination with microbial pathogens. Revision of traditional meat inspection is, therefore, required to improve the current situation, and in the EU a series of related scientific opinions have been produced (see Further Reading), that are expected to be incorporated into new food (meat) hygiene regulations to be introduced from 1 January 2006.


Current suggestions for improvement of traditional meat inspection procedures include the following:


1. Grouping of animals before slaughter according to level of risks they pose: lower-risk animals are those coming from integrated production systems (farms with quality assurance and providing full food-chain information – FCI).


2. Ensuring absence of public health hazards in animals through on-farm diagnostic programmes and control measures.


3. Confirming their lower-risk status by absence of any abnormalities at ante-mortem inspection.


4. Subjecting these lower-risk animals to a simplified post-mortem inspection procedure in which palpation and/or incision are largely omitted to avoid cross-contamination, unless absolutely necessary (e.g. tuberculosis detection). It is considered that in those animals public health risks from incision-mediated cross-contamination are higher than from the non-detection of certain conditions due to the omissions.


5. Removal of unfit tissues due to conditions posing no public health risk to be increasingly ensured through meat quality assurance, so to reduce overall amount of meat handling.


6. Maintaining detailed, full, physical post-mortem examination for higher-risk animals, to which the above is not applicable.


7. Controlling meat contamination from the main food-borne pathogens in healthy animals through abattoir process hygiene (e.g. GHP- and HACCP-based management systems).


Further reading

Anon. (2000) Opinion of The Scientific Committee on Veterinary Measures Relating to Public Health on Revision of Meat Inspection Procedures. European Commission, Health and Consumer Protection Directorate-General, Brussels.


Anon. (2001) Opinion of The Scientific Committee on Veterinary Measures Relating to Public Health on Identification of Species/categories of Meat-Producing Animals in Integrated Production Systems Where Meat Inspection May Be Revised. European Commission, Health and Consumer Protection Directorate-General, Brussels.


Anon. (2003) Opinion of the Scientific Committee on Veterinary Measures Relating to Public Health on Revision of Meat Inspection in Veal Calves. European Commission, Health and Consumer Protection Directorate-General, Brussels.


Anon. (2004a) Opinion of the Scientific Panel on Biological Hazards on Revision of Meat Inspection Procedures for Beef. EFSA Journal 141, 1–55.


Anon. (2004b) Opinion of the Scientific Panel on Biological Hazard on Revision of Meat Inspection Procedures for Lambs and Goats. EFSA Journal 54, 1–49.


Gracey, J., Collins, D.S. and Huey, R. (1999) Meat Hygiene. W.B. Saunders Company Ltd, London.


Wilson, A. and Wilson, W. (1998) Practical Meat Inspection. Blackwell, Oxford, UK.



6.4 Rapid Laboratory Tests


Introduction

Some laboratory tests may be required to obtain information additional to that derived from meat inspection. Large abattoirs can have a laboratory on-site; small operators generally do not have on-site laboratory facilities. However, many of these tests can be performed by the OVS under field conditions.


The rapid laboratory tests provide quick, field screening for presumptive positives and negatives. The judgement of carcass fitness then can be made if the owner agrees with the results. If agreement cannot be reached with the owner, further examination using more sophisticated laboratory methods must be conducted to confirm the results.


Rapid test to differentiate causes of jaundice/icterus

Yellow colouration in the tissues can originate from pigments contained in feeds (lipo-chromatosis), in which case older animals are more normally affected, and the meat is suitable for human consumption. However, this condition can also be due to jaundice, and the meat may not be suitable for human consumption. Furthermore, both causes of yellow colouration can exist in one animal. Initially, differentiation is attempted by visual examination of carcass tissues, to determine whether the yellow colouration is present in the fatty tissue only (likely from feeds) or in the connective tissues and eye whites (jaundice).


Indication: abnormal yellow colour, or its distribution, in tissues.


Procedure

• Take a 2 g sample of fat and boil with 5 ml 5% w/v NaOH for 1 min;


• cool under a tap, add 3–5 ml ether and shake; and


• allow to stand until the layers separate.


Interpretation of results

• Green to yellow colour in the aqueous (lower) layer indicates icterus;


• green to yellow colour in the solvent (upper) layer indicates the presence of carotenoid pigments, probably derived from feeds; and


• green to yellow colour in both layers indicates both icterus and feed-derived pigments are present.


Rapid test to determine the presence of anasarca/oedema in animals

Animals in poor condition may be emaciated and suffering from anasarca. Animals suffering from anasarca can be rapidly differentiated from healthy animals by examining the bone marrow. The bone marrow of healthy animals usually contains <25% water, while the bone marrow of animals with emaciation, anasarca, etc., contains >50% water.


Indication: anasarca in subcutaneous and connective tissue, or oedema accompanied by emaciation.


Procedure

• Place pieces of bone marrow (pea-sized) from a long bone in solutions of 32, 47 and 52% (v/v) ethanol.


Interpretation of results

• If the specimen floats in all three solutions, it contains <25% water and the animal is healthy but emaciated; and


• if the specimen sinks in two of the three solutions, or all three, it contains >50% water and the animal has anasarca.


Test for acetonaemia

Ketone bodies (acetone, acetoacetic acid, betahydroxybutyrate) can produce an unpleasant odour, which may be detected directly by smell alone. Acetonaemia is more prevalent in pregnant ewes, emaciated cows or cows in early lactation. These animals are usually presented for emergency slaughter, because they are showing signs of disease.


Indication: used to determine whether suspect animals have acetonaemia even if the condition cannot be detected using the sense of smell.


Procedure

• Shake 10 g diced meat in 15 ml cold water; and


• add 1 tablespoon of Rothera’s reagent, shake, and leave for 5 min.


Interpretation of results

• Purple permanganate colour in the supernatant fluid indicates the animal has acetonaemia.


Test for unusual odour, e.g. boar taint

Strong, unusual odours are generally unacceptable for consumers, although they may not represent a public health risk. Androstenone and skatole can both occur in edible tissues, but the taints may be more easily detected in fatty tissues.


Indication: to determine whether meat has an unusual/abnormal odour.


Procedure

• Take sample of fat or meat and place in cold water;


• heat (covered) to boiling; repeatedly test the odour of the steam;


• remove the tissue, cut immediately and test the odour released; and


• alternatively, fry the meat and test the odour released.


Interpretation of results

• Strong odours indicate the meat may be unfit for human consumption.


Test for imperfect bleeding

Imperfect bleeding can be caused by numerous factors, including disease, stress or inappropriate handling, and can result in meat that is unfit for human consumption. Blood vessels can be full of blood; the organs may drip when removed.


Indication: to determine whether the carcass has bled out properly.


Procedure

• Take 6 g fat-free muscle, cut, place in 14 ml water, and leave to stand for 15 min;


• withdraw 0.7 ml of supernatant into an agglutination tube; and


• add 1 drop malachite green reagent, mix, add 1 drop H2O2, shake, allow to stand for 20 min.


Interpretation of results

• A cloudy, green colour indicates imperfect bleeding; and


• a clear, blue colour indicates proper bleeding.


Test for meat species

Meats from differing animal species usually appear quite different. However, more novelty meat species (e.g. ostrich, kangaroo, etc.) are being consumed, and some of these can be difficult to differentiate. In addition, meat products can contain meat from a variety of animal species and should be labelled as such. This rapid test for meat species can only be conducted on uncooked meat.


Indication: to determine whether uncooked meat is correctly labelled.


Procedure

• Prepare rabbit antisera against individual animal species (purchased monoclonal antibodies or purchased antisera can be used);


• cut 1 g of uncooked meat finely and shake in 2 ml 0.85% saline;


• leave for 1 h to extract antigen; decant the supernatant;


• prepare a gel diffusion test using a commerical kit; these normally come with a template for drilling wells in pre-prepared gels; place the antigen extract in one template well and antibody/antisera in another; and


• place in a moist chamber at ambient temperature for 24 h.


Interpretation of results

• A positive visible precipitation line between reservoirs indicates the meat species is present in the antigen extract.


Test for tuberculosis

Animals with tuberculosis must not enter the human food chain.


Indication: caseous necrotic lesions in lymph nodes/organs.


Procedure (Ziehl-Nielsen staining)

• Prepare an air-dried, heat-fixed slide from a typical lesion in lymph nodes or organs;


• cover the slide with carbofuchsin and heat the stain so that it steams for at least 5 min; if the stain begins to evaporate add fresh stain; remove the flame if the stain begins to boil;


• decolourize by flooding the slide with acid alcohol for 20 s; add tap water immediately to stop decolourizing;


• counter-stain with methylene blue for 60 s; rinse the smear once again and blot dry; and


• observe for acid-fast organisms under the microscope.


Interpretation of results

• Observing acid-fast rods indicates the presence of Mycobacterium.


Test for residues of antimicrobials

Residues of antibiotics and other antimicrobial residues in meat are unacceptable in meat. Samples of kidney tissue are always examined in suspect animals, since the kidneys metabolize most antimicrobial compounds. However, muscle tissue (e.g. diaphragm) and suspect injection sites should also be included in this test.


Indication: recent medication suspected in animals.


Procedure

• Prepare microbiological agar (pH 6, 8 and 7.4) and cool to 45–50°C;


• inoculate molten agar with a standard antimicrobial-sensitive bacterial strain from a recognized culture collection (e.g. Bacillus subtilis spores) using a standard concentration;


• pour plates and leave to harden;


• one of the plates should contain trimethoprim, which is synergistic with sulphonamides;


• cut wells in the agar plates with a sterile cork borer and remove the plugs with a needle;


• prepare a homogenate of the tissue (e.g. kidney, muscle) by mixing 1 g of finely cut tissue with 2 ml of 0.85% saline;


• fill a well with a standard volume of the sample homogenate and leave to pre-diffuse at 4°C for 2 h; and


• incubate at 37°C for 16–18 h.


Interpretation of results

• Measure the diameter of clear zones of inhibition of bacterial growth surrounding the well;


• inhibition zones ≥2 mm are considered positive;


• for confirmation and quantification, more sophisticated methods must be used (e.g. HPLC, gas chromatography).


Meat examination for Trichinella

These tests require a microscope and more complex equipment, so may require dedicated laboratory space.


1. Artificial digestion method.


Procedure

• Take tissue samples (1 g for pig, 5 g for horse) from either the pillars of the diaphragm or the tongue, masseter or intercostal muscles;


• pool the tissue samples from 100 animals and grind them using a mortar;


• place in 1–2 l of artificial digestive fluid comprising 1% (w/v) pepsin (1/10,000) and 1% (v/v) hydrochloric acid (0.12M final concentration);


• stir for 3 h at 37°C (or 0.5–1 h at 44°C) using a magnetic stirrer;


• leave to settle for 15 min;


• discard the upper 2/3 of the fluid;


• pour the remaining fluid with deposit through a 355 (177–180 is also acceptable) μm mesh screen into a conical settling glass and allow to settle for 15–20 min; if required, wash the sediment with water and repeat the settling;


• drain 125 ml into a separatory funnel and leave to settle for 10 min;


• drain 22–27 ml from the bottom layer into a Petri dish and examine microscopically for coiled Trichinella larvae;


• if Trichinella larvae are found, the test must be repeated individually on tissues from each of the animals making up the pooled sample.


2. Trichinoscope (compression) method.


This method is less sensitive than the artificial digestion method, so is not recommended; it is indicated here for historic reasons and because it may be the only method available in certain countries.


Procedure

• Take tissue samples (1 g for pig, 5 g for horse) from either the pillars of the diaphragm, or the tongue, masseter or intercostal muscles;


• cut the tissue samples into 2 × 10 mm pieces, obtaining at least 28 pieces for pig or 56 for horse;


• compress the tissue pieces between glass (compressorium) plates until they become translucent;


• examine microscopically for coiled Trichinella larvae (40× magnification);


• the presence of coiled larvae within an oval cyst within an individual muscle fibre is positive.


3. ELISA test: stichosyte-cell antigens, glycoproteins 45–55 kDa.


This method is primarily applied for on-farm testing and monitoring.


Procedure

• Coat the wells in 96-well microtitre plates with 100 μl of antigen in pH 9.6 buffer and leave for 60 min at 37°C or overnight at 4°C;


• repeat the buffer – at pH 7.4 – wash and dry;


• dilute pig sera (or whole blood or tissue fluids) 1/10 to 1/100 in wash buffer;


• add 100 μl diluted pig sera to the wells and incubate at ambient temperature for 30 min;


• add 100 μl of affinity-purified rabbit anti-swine IgG-peroxidase conjugate (1/1000 dilution) and incubate for 30 min;


• add 100 μl of a suitable peroxidase substrate with 0.005% hydrogen peroxide (pH 5.6–6.0);


• after 5–15 min, read the colour density of the plates at 450 nm on an automated microplate reader;


• values four times higher than normal serum control are considered as positive.


Further Reading

Gracey, J., Collins, D.S. and Huey, R. (1999) Meat Hygiene. W.B. Saunders Company Ltd, London.


Wilson, A. and Wilson, W. (1998) Practical Meat Inspection. Blackwell, Oxford, UK.



6.5 Meat Inspection – Poultry


Introduction

In contrast to red meat animal species (cattle, pigs, sheep), ante-mortem inspection of poultry is not carried out at the abattoir, but on-farm. On arrival at the abattoir, poultry are slaughtered directly from transport vehicles, without any lairaging. Nevertheless, transport conditions and related poultry welfare should be checked.


In the UK, poultry meat inspection is based on The Poultry Meat, Farmed Game Bird Meat and Rabbit Meat (Hygiene & Inspection) Regulations 1995. The Official Veterinary Surgeon is responsible for ensuring that the post-mortem inspection of poultry is carried out in accordance with the requirements. The inspection can be assisted by non-veterinarians: poultry meat hygiene inspectors (PMHIs) or plant inspection assistants (PIAs).


Meat Inspection

Poultry meat inspection is carried out immediately after slaughter, and includes primarily visual examination of:


• whole defeathered birds before evisceration; this is not a statutory requirement, but is advisable, so that obviously diseased birds can be removed from the line to prevent contamination of equipment;


• surface of the carcass, excluding the head and the feet, except where these are intended for human consumption;


• viscera, which can remain (but not necessarily) attached to the carcass – with ensured correlation between carcass and viscera being essential; and


• body cavity.


Post-mortem inspection of Effile Birds (partly eviscerated poultry), in which the non-edible intestines are removed but the edible viscera remain attached to the carcass, includes:


• inspection of 5% of birds from the batch;


• examination focuses on external surface, viscera and body cavity;


• if no abnormal conditions are found, other birds are not inspected; and


• if any anomalies are found, all birds in the batch must be inspected.


Post-mortem inspection of birds that are subject to delayed evisceration must be carried out within the 15-day period after slaughter. These birds can be eviscerated either at the abattoir, or in a cutting plant that has been specifically approved for that; the meat inspection is carried out at the place of evisceration. In the meantime, these birds must be refrigerated at a temperature of not more than 4°C.


Judgement of meat fitness

Generally, the main reasons for judgeing meat as unfit for human consumption include the finding of evidence of disease, multiple tumours, cachexia, ascites and abnormal colour (insufficient bleeding), as well as meat contamination. All these conditions can be detected by visual examination of the carcasses and the viscera. The occurrence of some abnormal conditions can vary with the seasons. For example, heat stress is common in summer, respiratory disease and ascites in winter.


Causes for meat rejection commonly include E. coli infections, ascites and Marek’s disease. E. coli infections can produce a number of conditions such as colisepticaemia, cellulitis, salpingitis, egg peritonitis, coligranulom and swollen head syndrome. Ascites can be caused by hypoxia, primary liver disease or congenital cardiac defects. Marek’s disease is caused by a herpes virus and can produce visceral tumours, skin tumours and nerve infiltration.


Runting/Stunting Syndrome (caused by a virus) causes very uneven growth rate in a batch. This can lead to potential welfare problems because small birds can miss the stunner. These animals should be preferably culled on-farm.


Further Reading

Bremner, A. and Johnston, M. (1996) Poultry Meat Hygiene and Inspection. W.B. Saunders Company Ltd, London.


Jordan, F.T.W. and Pattison, M. (1996) Poultry Diseases. W.B. Saunders Company Ltd, London.



6.6 Sensory Evaluation of Meat


GEOFFREY NUTE


Introduction

Consumer confidence in the safety of meat and meat products is of increasing importance, especially since the range of products available continues to increase. Consumers demand food that is of excellent eating quality, safe to eat, of high nutritional value and has an increased shelf life.


A recent study Ngapo et al. (2003) used focus groups in four countries (France, UK, Sweden and Denmark) to identify consumer attitudes to pig production and pork quality. UK consumers cited cleanliness of the place of purchase, unbroken packaging and healthiness as some of their criteria when purchasing pork. Interestingly, there was little or no discussion about food-borne illnesses related to the consumption of pork, probably as a result of media coverage mainly attributing microbiological spoilage to poultry products.


Decontamination of meat covers a whole range of different processes, ranging from irradiation techniques (high consumer resistance) to acid dips or sprays (low consumer awareness) (see Chapter 5.6). Microbiologists concentrate on the reduction of microorganisms in/on the meat and on the resultant improved safety of the meat. Sensory analysts concentrate on the eating quality of the meat and whether or not there are changes in the sensory attributes – and hence consumer satisfaction – as a result of applying decontamination techniques.


This chapter describes what constitutes a sensory panel and gives examples from the literature where these techniques have been documented and the sensory approach used.


Sensory Panel

In much the same way that we would check the sensitivity of an instrument, it is necessary to ascertain the sensitivity of the potential assessors. These procedures are documented in The British Standards Institution BS7667, part 1, 1993 (BSI, 1993). This standard defines the materials and methods used in the screening process, which is a way of determining whether or not a person is suitable for making sensory assessments.


The training in the first instance is not specific to a particular food product, but rather is a series of tests to ascertain the sensory acuity of the candidate.


The types of screening tests used are aimed at determining: impairment, sensory acuity and evaluation of a candidate’s potential for describing and communicating sensory perceptions.


Colour vision can be checked either by a qualified optician or by sensory analysts familiar with the Ishihara test (Ishihara, 1967). Further colour discrimination tests, e.g. the 100-Hue test (Farnsworth, 1957), are used to identify the discriminational abilities of assessors. This test is different from the Ishihara test in that its prime purpose is to classify those individuals with normal colour vision into categories of superior, average and low colour discrimination.


Ageusia (lack of sensitivity to taste stimuli) and anosmia (lack of sensitivity to olfactory stimuli) are the terms used to describe the potential assessors’ basic taste/odour sensitivity, or possible lack of sensitivity, at average recognition thresholds.


The taste test uses substances at known concentrations and covers the basic sensations of sweetness, acidity, bitterness, saltiness, astringency and metallic.


Odour recognition is a simple sniff test, where potential assessors are given a range of familiar odours and are required to identify them using simple descriptions.


Sensory Tests

These can be categorized into, ‘difference tests’, ‘category tests’, ‘ranking and scaling tests’ and ‘profiling tests’. The former two groups of tests are probably the most useful when dealing with decontamination issues, and examples of their usage are given below.


Difference tests

Van der Marel et al. (1989) investigated the use of 1% (v/v) lactic acid treatment on the sensory quality of fresh broiler chickens. The chickens were immersed at three stages during processing, defeathering, evisceration and after air-chilling. Control birds were treated in a similar way using tap water as the immersion treatment. The carcasses were stored at 0°C for 2 days in trays. Samples of thigh and drumstick were grilled for 30 min and sub-sampled to provide sufficient samples for 12 assessors.


Each assessor received one control and one treated sample of thigh and drumstick over two sessions, respectively.


The paired comparison test (BS5929: part 2, BSI, 1982) was used where p = 0.5, i.e. the probability of selecting the treated sample over the control and vice versa is 50%.


This test is usually a directional test, where assessors are asked to state the difference in intensity of a particular sensory attribute. However, in this work the non-directional test was used, since assessors were asked which sample they preferred. Therefore, this is a two-tailed test and the expected number of choices required for a significant result at the 5% level of probability in a particular direction is 32/48. In this test 26 assessors preferred the control samples and 22 preferred the treated samples. It was concluded that using lactic acid as a decontaminant would not be a problem in terms of eating quality.


The duo–trio test (BS 5929: part 8, BSI, 1992) is statistically less powerful than the triangular test described below, and although samples are presented as a triad, one of the samples is labelled as a reference sample.


Duo–trio tests were used by Janky and Salman (1986) to investigate differences in poultry meat from carcasses that had been water-chilled or brine-chilled. After chilling, samples were either packed in ice or blast-frozen. The main objective of the trial was to determine the effect of chill-packaging with brine-chilling and its influence on texture. However, there was an inference that the brine treatment might also reduce bacterial counts, although this was not tested in this trial.


Samples were battered and breaded, then deep-fried and allowed to cool overnight. Prior to the sensory tests the batter was removed and samples cut into small pieces for distribution to the panel. Both light and dark meat were assessed. In at least half of the panels, assessors were able to distinguish between ice-packed and chill-packed products. In light meat using the brine solution there were no significant differences between the two packaging treatments. In dark meat there were significant differences between the two packaging treatments.


The authors concluded that the differences found by the sensory panel were in accordance with shear force values that showed chill-packaging produced a toughening effect on texture which was not observed in brine-chilled samples.


The triangular test method (BS5929: part 3, BSI, 1984) was used by Dickens et al. (1994) in a study on cooked chicken breast, to ascertain whether the immersion of chickens in an acetic acid dip (0.6%) during processing could be detected in the cooked product.


The probability of selecting the ‘odd’ sample is 1/3. In this test assessors are presented with three samples, two of which are identical; their task is to select the ‘odd’ sample on the basis of difference only. There are six possible combinations of tasting order: ABB, AAB, ABA, BAA, BBA, BAB, and these are balanced across all assessors.


Two methods of preparation were used, boil-in-the-bag (water-cooked) and oven-roast. All assessments were completed under red light to reduce appearance effects. In all, 60 triangles were presented for each preparation method. In the water-cooked samples, taking the pooled assessors’ results, there were 24/60 correct identifications, and in the oven-cooked tests, 29/60 correct identifications. The requirement for a positive result requires 30/60 correct identifications, and therefore in these tests the use of an acetic acid dip would not produce significant differences in sensory quality, whilst the Enterobacteriaceae (ENT) Log10 counts were reduced from 4.51 to 3.80.


Category tests

Difference tests are very useful in preliminary studies, since non-significant results indicate that the samples are not perceived as different; however, when there are differences it is necessary to identify which sensory attributes are different and how they are affected by the treatments under test.


Capita el al. (2000) investigated the use of trisodium phosphate (TSP) dodecahydrate solutions to reduce Salmonella contamination in poultry meat. In this study three concentrations of TSP, 8%, 10% and 12% (w/v) were used and these were compared using chicken thighs. Nine-point hedonic category scales for colour, smell and overall acceptability (where 1 = dislike extremely and 9 = like extremely, with a central category of neither like or dislike) were used in this trial.


The consumer panel rated both raw and cooked chicken thighs at day 0 (immediately after dipping) and after 7 days’ storage. At day 0 consumers found significant differences in 10% and 12% TSP samples and these differences were related to colour and smell, whereas 10% TSP samples were significantly preferred and in 12% TSP, where colour and overall acceptability were rated higher.


At 7 days’ storage the colour liking of chicken samples dipped in 12% TSP were significantly lower than those treated with 8 and 10% TSP.


In cooked samples after 7 days’ storage there were significant differences observed in colour, flavour and overall acceptability. The colour liking of 12% TSP samples was significantly less than for the control samples. In terms of smell there were no significant differences between treatments, but in overall acceptability the 12% TSP samples were the least preferred whilst there was no difference between the other treatments.


In this trial it was concluded that the use of TSP could have potential to sanitize chicken carcasses.


Hathcox et al. (1995) compared the use of TSP and lactic acid/benzoic acid on consumer acceptance of fried chicken breasts and thigh meat. 180 whole chickens were washed in either control tap water, 12% trisodium phosphate (TSP) or 0.5% lactic acid/0.05% sodium benzoate (LB). Consumer panellists evaluated raw, treated whole chickens as well as fried breast and thigh samples. Nine-point hedonic category scales were used throughout the trials. Ratings for whole raw chickens showed that there were significant differences in acceptability, colour ratings and purchase intention. At 0 days and after 7 days’ storage, LB samples were rated significantly lower than TSP and control samples for all attributes.


When tasting fried chicken, consumers did not differentiate Control, TSP or LB samples for texture, flavour, moistness or overall acceptability in either breast or thigh samples. In breast acceptance LB samples were rated lower than TSP samples, but were not significantly different from control samples.


The authors concluded that 12% TSP or 0.5%/0.05% sodium benzoate solutions had potential as dips to sanitize chickens intended for frying before serving to consumers.


Griffiths et al. (1978) stated that poultry diets were a potential source of Salmonellae and could cause infection in breeding stock, either by egg transmission to their progeny or directly by infecting chicks that had been free of infection.


Methyl bromide had been used in the past to destroy bacteria, fungi and insects in soils, stored crops and some processed foods. It can also be used as a fumigant for poultry food stored in paper sacks, since methyl bromide disperses rapidly when paper sacks are exposed to air. However, there was concern that there could be a ‘taint’ or changes in flavour of the meat from broilers that had received feed that had been fumigated with methyl bromide. Broilers were fed on control and treated commercial diets with methyl bromide gas at 69 and 25% over the value recommended for elimination of Salmonellae.


Tests with both a sensory panel and a consumer panel were conducted. The sensory panel used modified category scales and were also asked to describe the flavour and odour of the samples, using a different technique from control procedure where 0 = no difference, 1 = slight difference, 2 = moderate difference and 4 = large difference. The treated samples were significantly different from the controls and the flavour descriptors indicated that the samples were, ‘cabbagy’, ‘bloody’, ‘metallic’, ‘rancid’, ‘sharp’ and ‘onion’. The conclusion from the sensory data indicated that the treated samples were tainted.


The home consumer panel (n = 52) used a simple three-point scale of good, fair or poor. The odour and flavour of the cooked meat was assessed and rated by the cook. Other household members rated cooked chicken flavour separately. The results showed that the treated chickens had a higher percentage of poor birds and a lower percentage of good birds than the controls. The ratings given by the consumers were analysed for the frequency with which the control birds were preferred over the treated birds. This showed that in the majority of cases, the control birds were preferred.


The authors concluded that a trained sensory panel found a significant taint in the roasted meat from birds fed on fumigated food. More than 50% of consumers also rated control birds better than treated birds.


Conclusions

When considering methods of decontamination of meat for human consumption, there are probably four stages in developing a new treatment. Stage 1 involves a study of the efficiency of the decontamination in terms of the reduction in bacterial counts. Stage 2 involves the use of a trained sensory panel to investigate appearance, odour and flavour of the meat for possible ‘taint’ or other sensory attribute effects. Stage 3 investigates consumer acceptability of the meat. Stage 4 involves consumer attitudes to the introduction of new treatments and whether or not the image of ‘wholesomeness’ is affected. Following these stages should result in meat that retains sensory attributes and eating enjoyment whilst benefiting from improved safety and shelf life properties.


References

BSI (1982) Sensory Analysis of Food. Part 2. Paired comparison test. BS5929. British Standards Institution, Milton Keynes, UK.


BSI (1984) Sensory Analysis of Food. Part 3. Triangular test. BS5929. British Standards Institution, Milton Keynes, UK.


BSI (1992) Sensory Analysis of Food. Part 8. Duo–Trio test. BS5929. British Standards Institution, Milton Keynes, UK.


BSI (1993) Assessors for Sensory Analysis. Part 1. BS7667. Guide to the Selection, Training and Monitoring of Selected Assessors. British Standards Institution, Milton Keynes, UK.


Capita, R., Alonso-Calleja, C., Sierra, M., Moreno, B. and Camino Garcia-Fernandez, M. (2000) Effect of trisodium phosphate solutions washing on sensory evaluation of poultry meat. Meat Science 55, 471–474.


Dickens, J.A., Lyon, B.G., Whittemore, A.D. and Lyon, C.E. (1994) The effect of acetic acid dip on carcass appearance, microbiological quality and cooked breast meat texture and flavour. Poultry Science 73, 576–581.


Farnsworth, D. (1957) The Farnsworth–Munsell 100-Hue Test. Munsell Colour Company Inc., Baltimore, Maryland.


Griffiths, N.M., Hobson-Frohock, A., Land, D.G., Levett, J.M., Cooper, D.M. and Rowell, J.G. (1978) Fumigation of poultry food with methyl bromide; effects on flavour and acceptability of broiler meat. British Poultry Science 19, 529–535.


Hathcox, A.K., Hwang, C.A., Resurreccion, A.V.A. and Beuchat, L.R. (1995) Consumer evaluation of raw and fried chicken after washing in trisodium phosphate or lactic acid/sodium benzoate solutions. Journal of Food Science 60, 604–605.


Ishihara, I. (1967) Tests for Colour Blindness. Kanehara Shuppan Co. Ltd, Tokyo.


Janky, D.M. and Salman, H.K. (1986) Influence of chill packaging and brine chilling on physical and sensory characteristics of broiler meat. Poultry Science 65, 1934–1938.


Ngapo, T.M., Dransfield, E., Martin, J.F., Magnusson, M., Bredahl, L. and Nute, G.R. (2003) Consumer perceptions: Pork and pig production. Insights, from France, England, Sweden and Denmark. Meat Science 66, 125–134.


Van der Marel, G.M., De Vries, A.W., Van Logtestijn, J.G. and Mossel, D.A.A. (1989) Effect of lactic acid treatment during processing on the sensory quality and lactic acid content of fresh broiler chickens. International Journal of Food Science and Technology 24, 11–16.



6.7 Certification and Marking of Foods of Animal Origin


ALISON SMALL


Certification

Foods of animal origin travel freely within the country of origin, and between states united by common trade agreements, such as within the EU. In such trade, the foods are accompanied merely by a Commercial Document, which is used as evidence in tracing of foods. The commercial document is generated by the premises of origin of the food, and contains information such as the name and address of consignor and consignee, the approval number of the premises from which the food is to be transported, and the quantity and description of the product transported, including date of freezing in the case of frozen foods. Where foods of animal origin are to be transported to countries not included within the common trade agreement, known as ‘third countries’, veterinary certification of the food is required.


The veterinarian carrying out certification of foods of animal origin must be authorized by the competent authority of the country in which he/she is working, and will have undergone appropriate training in export procedures. The certificate to be completed is supplied by the competent authority, and contains particular declarations required by the importing country. Most certificates have been agreed with the importing country, but on occasion, full agreement has not been reached, and the certificate contains declarations of information judged to be appropriate by the competent authority of the exporting country.


Certification, of any sort, is an activity that can hold the greatest hazard to a veterinarian’s professional reputation and career. False certification can be considered to be negligence, or could constitute a criminal offence. In the UK, the Royal College of Veterinary Surgeons Guide to Professional Conduct gives 12 Principles of Certification, which have been adopted internationally, and all parties involved in certification are advised to adhere to these principles.


It is important to read the certificate carefully before signing, and ensure that all declarations can be made truthfully and factually. Declarations can only be made on subjects that the certifying veterinarian knows to be true, or that are supported by documentary evidence, such as a certificate from the competent authority in the case of freedom from notifiable disease, or a certificate from the veterinarian involved in official controls at a premises earlier in the food chain. No blank spaces should remain on completion of the certificate, and all parts should be signed and dated, with the personal stamp of the certifying veterinarian applied. It is important to keep copies of the certificate and any supplementary evidence or documentation in the event of any challenge.


Marking of Foods of Animal Origin

Identification labelling of foods of animal origin is important. Proper identification allows tracing of the food back to the premises of production and – ideally – to the farm or even the animal of origin. Full traceability is vital in the event of a disease outbreak, or in the event of contaminants being found within a food product. Traceability allows recall of potentially unsafe foods, and also assists in the identification of the point in the food chain where contamination may have arisen. Correct identification of the source of illegal contaminants is vital to good enforcement of legislation. Individual countries and states have local rules on labelling of foods of animal origin; however, in general, foods will be marked with an identification mark showing the country of origin, and an approval number of the production plant where that food was produced. This therefore means that the component parts of a food sold at retail level may at some point in the chain have carried different approval numbers, as it progressed through the manufacturing process. For example, a pork sausage started as a pig, which carried the identification mark of the farm of origin. Then, the pig was processed and the carcass carried the approval number of the slaughterhouse. It may then have been sold to a cutting premise. From here the cut meat, bearing the approval number of this factory, is transferred to the sausage factory, and ultimately bears the identification mark of this final premises when displayed in the retail store. Each premises in the chain must keep records to allow that sausage to be traced back to the farm of origin.


In the EU, carcasses leaving a slaughter facility would bear a Health Mark, giving the required information of country and premises of origin. This Health Mark could be one of several different shapes, indicating the class of meat identified. For example, meat produced in export-approved premises would carry an oval mark, meat produced from animals that had been slaughtered on-farm as special emergency slaughter would carry a square mark, and wild game meat would carry a pentagonal mark. These Health Marks are under the control of the veterinary inspection service, and are an indication that the meat has been produced in accordance with the requirements of the current legislation, and has passed both ante-mortem and post-mortem meat inspection procedures. The Health Mark could also carry a code number indicating the individual official carrying out the health inspection of the meat. The dimensions of the mark and its lettering are laid down in the legislation (Fig. 6.4), and the colourant used in marking meat must be an approved food-grade dye. It is very important that the Health Mark is legible. Offals may be branded with the Health Mark, using a hot iron.


The Health Mark may be modified in certain circumstances. For example, carcasses from boars that demonstrate a sexual odour that is not pronounced, and may be used for manufacturing purposes only, may carry the Health Mark overlaid by two parallel horizontal lines, or carcasses from animals under movement restrictions due to notifiable disease control may carry the Health Mark overlaid by a cross.


image

Dec 15, 2017 | Posted by in GENERAL | Comments Off on Post-mortem Meat Inspection
Premium Wordpress Themes by UFO Themes