Assessment of organoleptic postmortem inspection techniques for bovine offal

OBJECTIVE: To evaluate organoleptic postmortem inspection techniques for bovine livers and kidneys. STUDY DESIGN: At Australian export abattoirs, bovine liver and kidneys are assessed and graded by qualified meat inspectors during normal operations. Over a 12-month period at a large abattoir in eastern Australia during 1997 and 1998, a sample of these organs was reassessed independently using a range of pathological and microbiological methods. Agreement between routine inspection and independent assessment was evaluated using methods of inter-rater agreement. RESULTS: A total of 944 livers and 1374 kidneys were included in the study. All of these organs had been classified during routine inspection. The authors examined 363 livers and 329 kidneys both grossly and histologically, including 36 livers and 14 kidneys that were also subjected to microbiological examination. All other organs were only examined grossly. There was only a moderate level of agreement between the routine and independent assessment methods. For livers, the percentage agreement was 80.2%, McNemar's test of symmetry 55.2 (3 degrees of freedom, P < 0.001) and kappa 0.63. For kidneys, the percentage agreement was 67.8%, McNemar's test of symmetry 9.9 (1 df, P = 0.002) and kappa 0.35. CONCLUSIONS: The results reinforce concerns from a number of authors about organoleptic postmortem inspection. Risk assessment methodologies offer the opportunity to modify inspection techniques in a manner that is most relevant to current public health concerns.     

Risk assessment of organoleptic postmortem inspection procedures for pigs

A systematic quantification of foodborne hazards in abnormal and normal tissues of pig carcases was undertaken to provide a risk-based assessment of the effectiveness of traditional organoleptic meat inspection. A total of 36,059 pigs, representing all major pig-producing areas and systems in Australia, were inspected on a seasonal basis at three abattoirs over 12 months. The prevalence of grossly detectable abnormalities of possible food-borne disease significance was recorded. A subset of the grossly detectable abnormalities, together with tissues classified by inspection as normal (controls) were submitted for the detection of a broad range of food-borne hazards. The potential exposure of consumers to hazards in fresh pork was characterised as the number of carcases per 10,000 containing hazards in selected tissues. The results indicated that the level of exposure of consumers to microbiological hazards in fresh pork is unlikely to be reduced significantly by the detection and removal of gross abnormalities in the tissues examined. On the basis of carcase throughput, the rate of contamination of normal lymph nodes was commonly 100 times higher, and no hazards were isolated from two types of grossly abnormal nodes. While further processing, cooking and handling may alter the exposure characterisation, the study nevertheless identifies the proportional contribution of abnormal and normal tissues to risks to consumers and clearly identifies the need for consideration of 'visual only' inspection in the re-evaluation of traditional inspection procedures.     

Comparative assessment of postmortem inspection and immunochromatographic techniques for the detection of bovine tuberculosis in slaughter cattle in Nigeria

Animals with tuberculosis pose some risks to humans, especially in developing countries of the world. In this study, postmortem inspection (PMI) and immunochromatographic assay (ICA) techniques were compared for the detection of bovine tuberculosis (BTB) in slaughter cattle in Enugu State, Nigeria using culture as the gold standard. A cross-sectional study was conducted from January–June, 2011 on animals presented at four purposively selected slaughterhouses in the study area, involving a total of 500 randomly selected animals. Blood samples were collected from the jugular veins of selected animals and serum samples harvested for ICA. Thorough PMI was carried out and tissue samples from the lung, liver, intestine, and lymph nodes were collected, with or without lesions for culture; from the animals examined, culture detected 11 positive cases giving a prevalence rate of 2.2 %, whereas PMI detected 22 positive cases including 7 (out of the 11) positive cases detected by culture, giving a prevalence rate of 4.4 %. Fifteen of the cases detected as positive by PMI were negative by culture. Therefore, the sensitivity and specificity of PMI were 64 and 97 %, respectively. ICA detected 59 positive cases including 10 of the 11 positive cases detected by culture, hence, a prevalence rate of 11.8 %. Forty-nine of the cases detected as positive by ICA were negative by culture. Hence, the sensitivity and specificity of ICA were 91 and 90 %, respectively. In conclusion, the performance of ICA was found sufficiently high to support its use in BTB surveillance and control in cattle in Enugu State, Nigeria.     

Risk-based evaluation of postmortem inspection procedures for pigs in Australia

The results of traditional (incision) and risk-based (visual) postmortem inspection procedures were compared on groups of approximately 30,000 pigs. The performance characteristics used as a basis for comparison included the non-detection rates of grossly detectable abnormalities, the microbiological contamination rates of carcases and boned product, the association of reactive lymph nodes with carcase condemnation and the achievement of 'finished product standards' for 'wholesomeness'. It was estimated that 6 per cent of all cases of abscessation and 28 per cent of all cases of arthritis were undetected by the traditional method, and the comparable figures for the risk-based procedure were 19 per cent and 39 per cent. However, when the rates of contamination of undetected abnormalities with foodborne hazards and other carcase contamination parameters were taken into account, it was concluded that both inspection systems were likely to result in a very similar level of consumer protection. Any increase in potential exposure to foodborne hazards in the abnormalities undetected by risk-based inspection would be insignificant in comparison with the potential exposure to foodborne hazards resulting from contaminated 'normal' lymph nodes and carcase surfaces. There were no statistically significant differences between the two procedures in the contamination rates of pre-chill carcases or boned retail products with Salmonella and Yersinia species.     

A risk-assessed evaluation of postmortem meat inspection procedures for ovine thysanosomiasis

A risk assessment model was used to evaluate 4 meat inspection procedures for routine detection of Thysanosoma actinioides, a tapeworm that commonly infests the bile duct system of adult sheep in the United States. The overall sensitivities of different procedures ranged from 11.96 to 58.70%, and the nondetection rates per 1,000 viscera sets that passed inspection ranged from 38 to 77. On the basis of performance attributes for each procedure produced by the risk assessment model, the consumer was exposed to an aesthetic defect that was in 9 to 17 of every 1,000 livers passed for human consumption. The amount of wastage was also identified (3 to 39 livers/1,000 passed). Viewing of the incision site of the common hepatic duct was the most preferable routine inspection procedure, and matched pair analysis revealed that there was no additional benefit in combining this procedure with routine expression of a portion of bile from the gallbladder.     

Causes and implications of bovine organs/offal condemnations in some abattoirs in Western Nigeria

Food animals though sources of protein and revenue to man, also serve as vehicles of disease transmission. This work reviews a three year record of slaughtered cattle in 12 abattoirs/slaughter slabs in western Nigeria to determine the economic and public health issues associated with their disease conditions. Out of 641,224 cattle slaughtered, 51,196 (7.98%) were attributable to 14 diseases/conditions including tuberculosis, pneumonia, fascioliasis, pimply gut, paramphistomosis, cysticercosis, dermatophilosis, tonsillitis, taeniasis, ascariosis, abscess, mange, mastitis and immature fetuses. Pneumonia (21.38%), fascioliasis (20.28%) and tuberculosis (7.95%) were major reasons for condemnations; least being ascariosis (0.01%). The lungs (45.66%) and liver (32.94%) accounted for most organ condemned while the heart (0.02%) was the least affected. The proportions of pneumonia, fascioliasis and immature fetuses observed were not statistically different (Mean = 3895.7; 3654.0; 3467.3); however, a significant difference existed with other conditions (Mean_A = 3895.7; 3654.0; 3467.3; Mean_B = 1359.7; 1057.7; 510.3). Organs/offal condemnations constituted loss of revenue and animal protein as 124,333 kilogrammes worth of meat valued in Naira at N41,613,043 (332,904) was lost over the period giving an average of N13,871,014 (332,904) was lost over the period giving an average of N13,871,014 (110,968) annually. This, coupled with fetal wastage represented an economic loss; with associated public health implications.     

Comparison of two different meat inspection techniques

Field studies of meat inspection procedures in three different slaughter houses were performed in Germany, in 1996. In total 22,634 fattening pigs from 63 farms were inspected twice, using a visual and the traditional (mandatory inspection system) procedure. Statistical analysis was performed using the rate of ND+ (Non-Detected Positives) for both visual and traditional inspection. Neither the visual nor the traditional methods detected all lesions which were supposed to be in the lot of animals inspected. Some of the results could be explained by the nature and obviousness of the respective lesion. Conclusions regarding the future performance of inspection should not be drawn before a formal risk analysis procedure for the particular lesion has been done.     

Evaluation of techniques for counting bovine platelets.

Visual and electronic techniques for counting bovine platelets were investigated. The reference method used was hemacytometer counting of platelets in whole blood diluted with 0.85% NaCl solution. A whole blood platelet-rich plasma technique was imprecise and inaccurate. Isopycnic centrifugation of blood diluted in 8.01% NaCl solution (same density as platelets) was a precise technique, but the whole blood platelet count was underestimated. The most precise and accurate technique investigated was unit gravity sedimentation of a 1:100 dilution of blood with 10 ml of Isoton followed by electronic counting of platelets in the supernatant. This technique correlated very well with visual counting of bovine platelets (N = 77, y = 55 + 0.80x, r = 0.89, P less than 0.01).     

Sarcomere length influences postmortem proteolysis of excised bovine semitendinosus muscle

The interaction between sarcomere length and postmortem proteolysis as related to meat tenderness is not clear. The extent of thick and thin filament overlap alters actomyosin binding and may alter substrate availability during aging-induced tenderization. The objective of this study was to determine the influence of sarcomere length on proteolytic degradation in beef. Strips from bovine semitendinosus were either stretched 40% and restrained or allowed to shorten unrestrained in an ice bath. After rigor completion, 0.6-cm cross sections were fabricated and were randomly assigned to 2, 4, 7, or 10 d of aging treatments. Myofibrils were isolated for sarcomere length determination. Samples were collected and frozen for shear force analysis, and muscle proteins were extracted for SDS-PAGE and Western blotting analyses to determine troponin T (TnT) proteolysis. Sarcomere length was greater (P < 0.01) in stretched muscle samples compared with shortened samples (2.57 vs. 1.43 microm, respectively). Correspondingly, shear force values were greater (P < 0.05) in shortened samples than stretched samples. Western blots revealed the presence of 3 major intact TnT bands that diminished with time postmortem and 4 bands (TnT degradation products) that accumulated during postmortem storage. Quantification of intact TnT showed increased (P < 0.05) proteolysis at 4 and 7 d postmortem in samples with long sarcomeres. By 10 d, only traces of the greatest molecular weight intact TnT band were evident in both shortened and stretched samples, suggesting this TnT band may be more susceptible to proteolysis than other intact TnT bands. Degradation products of TnT appeared earlier postmortem in samples with long sarcomeres. The 30-kDa TnT fragment appeared after 7 d of postmortem storage in samples with long sarcomeres but not until 10 d in muscle containing short sarcomeres. Collectively, these data show that postmortem TnT proteolysis is sarcomere length-dependent and suggest that thick and thin filament overlap may influence the postmortem aging process in beef.     

Tropical fish medicine. Biopsy and rapid postmortem techniques for diagnosing diseases of fish

Biopsy and rapid postmortem techniques are simple to perform with commonly available instruments. Because the skin and gills are the target organs for so many infectious agents, biopsy is a very useful tool in pet fish medicine. The major requisite for successful diagnosis using biopsy materials is the ability to recognize different taxonomic groups of pathogens. Many of these pathogens may be present in clinically normal individuals, and their importance must be interpreted with other clinical findings. Rapid postmortem techniques can identify several common systemic diseases affecting pet fish. The usefulness of these procedures is highly dependent on the state of tissue preservation of the specimens presented.     

3项实验综合检验判定病死肉

在肉品卫生质量检验中,鉴别病、健肉有很多种理化方法,通过多年的研究及多方面的探讨,我们于1997年初开始引进原解放军农牧大学科研成果-动物性食品兽医卫生检验箱中的病死畜禽肉综合检验技术,经过实验室对照试验及小区试验,最后在全省范围内推广.     

牛超排技术的研究

用４组药物组合：（１）ＰＭＳＧ＋ＰＧＦ２ａ；（２）ＰＭＳＧ＋ＰＧＦ２ａ＋激光照射；（３）ＦＳＨ＋ＰＧＦ２ａ；（４）ＦＳＨ＋Ｃｔｏｐｒｏｓｔｅｎｏｌ，超排处理３２２头次供体牛。共采卵１６６３枚（头均５．８１±４．６８），可用胚胎９８０枚（头均３．４３±３．９４，占５８．９％）。（３）、（４）两组胚胎可用率及可用胚胎数高于（１）、（２）组（ｐ＜０．０５）；黄牛胚胎可用率高于奶牛（ｐ＜０．０１）；育成牛胚胎可用率高于经产牛（ｐ＜０．０１）；供体牛前两次超排效果更好（ｐ＜０．０５）。     

Comparison of postmortem techniques for the detection of Mycobacterium bovis in white-tailed deer (Odocoileus virginianus).

A retrospective study of various diagnostic postmortem techniques used in a 4-year surveillance program for detection of Mycobacterium bovis infection in wild white-tailed deer (Odocoileus virginianus) was conducted. The tests evaluated were routine histopathology, acid-fast staining, detection of acid-fast bacilli in culture, and an M. tuberculosis group-specific genetic probe applied to pure cultures. Each of these techniques were compared with a reference or "gold standard" of mycobacterial culture and identification. Histopathology, the most rapid form of testing for M. bovis infection in white-tailed deer samples, had a sensitivity of 98% and a specificity of 87%, resulting in a positive predictive value of 94%. The detection of acid-fast bacilli by staining was less sensitive than histopathology (90%), but its higher specificity (97%) resulted in a positive predictive value of 99%. The detection of acid-fast bacilli on culture was both highly specific (93%) and sensitive (100%). The group-specific genetic probe had the highest sensitivity and specificity and produced results in complete agreement with those of mycobacterial culture, suggesting that this technique could be used as the new "gold standard" for this particular wildlife tuberculosis surveillance program.     

Effect of postmortem storage on activity of mu- and m-calpain in five bovine muscles

An in situ system involving incubation of 60- to 80-g pieces of muscle at 4 degrees C under different conditions was used to determine the effects of time of postmortem storage, of pH, and of temperature on activities of mu- and m-calpain activity in bovine skeletal muscle. Casein zymograms were used to allow measurement of calpain activity with a minimum of sample preparation and to ensure that the calpains were not exposed to ionic strengths of 100 or greater before assay of their activities. In 4 of the 5 muscles (longissimus dorsi, lumbar; longissimus dorsi, thoracic; psoas major; semimembranosus; and triceps brachii) studied, mu-calpain activity decreased nearly to zero within 48 h postmortem. Activity of m-calpain also decreased in the in situ system used but at a much slower rate. Activities of both mu- and m-calpain decreased more slowly in the triceps brachii muscle than in the other 4 muscles during postmortem storage. Although previous studies have indicated that mu-calpain but not m-calpain is proteolytically active at pH 5.8, these studies have used calpains obtained from muscle at death. Both mu- and m-calpain are proteolytically inactive if their activities are measured at pH 5.8 and after incubating the muscle pieces for 24 h at pH 5.8. Western analysis suggested that neither the large 80-kDa subunit nor the small 28-kDa subunit of m-calpain was autolyzed during postmortem storage of the muscle pieces. As has been reported previously, the 80-kDa subunit of mu-calpain was autolyzed to 78- and then to a 76-kDa polypeptide after 7 d postmortem, but the 28-kDa small subunit was not autolyzed; hence, the autolyzed mu-calpain molecule in postmortem muscle is a 76-/28-kDa molecule and not a 76-/18-kDa molecule as previously assumed. Because both subunits were present in the postmortem calpains, loss of mu-calpain activity during postmortem storage is not due to dissociation of the 2 subunits and inactivation. Although previous studies have shown that the 76-/18-kDa mu-calpain molecule is completely active proteolytically, it is possible that the 76-/28-kDa mu-calpain molecule in postmortem muscle is proteolytically inactive and that this accounts for the loss of mu-calpain activity during postmortem storage. Because neither mu- nor m-calpain is proteolytically active at pH 5.8 after being incubated at pH 5.8 for 24 h, other proteolytic systems such as the caspases may contribute to postmortem proteolysis in addition to the calpains.     

Maggots, mutilations and myth: Patterns of postmortem scavenging of the bovine carcass

Based upon what is known about the habits of common carrion eaters in Alberta, we review the patterns of postmortem scavenging of carcasses of cattle. We then compare with these patterns those reported in the lay press and by veterinarians investigating cattle mutilations in Alberta. We conclude that the so-called “mutilation” of cattle in Alberta was due to scavenging of carcasses and further conclude that claims of human involvement in such incidents require, as a first condition, that postmortem scavenging of the carcass be excluded.     

Subpopulations of bovine lymphocytes separated by rosetting techniques

A combination of E-rosetting techniques with both neuraminidase- and AET-treated sheep erythrocytes (RBC) was used to enumerate subsets of bovine T lymphocytes. Direct (anti-Ig) rosetting procedures were used to enumerate B lymphocytes bearing surface immunoglobulin (Ig). Approximately 10% of bovine peripheral blood lymphocytes formed rosettes only with neuraminidase-treated RBC; 20% formed rosettes with either neuraminidase- or AET-treated RBC; 30% formed rosettes only with AET-treated RBC; 25% possessed surface Ig, as shown by rosette formation with anti-Ig-coupled RBC; and the remaining 15% lacked both E receptors and surface Ig. These five populations were physically separated by centrifugation on Ficoll-Diatrizoate and recovered for functional analysis. The procedures reported here should be useful for the identification of lymphocyte populations responsible for recognition, effector, and cooperative functions in the bovine immune system.