Results of the evaluation of food chain information for a risk-oriented meat inspection

In a scientific project 469 slaughter groups originating from 39 farmers with 37.222 pigs in total were investigated concerning the usefulness of the food chain information. A standard statement does not include enough relevant information for the official veterinarian in the slaughterhouse to do a risk-based meat inspection. Even the food chain information for the visual meat inspection, which has certain limits, shows only farms, where the animals are of good health. Groups of fattened pigs with an extreme high rate of mortality and many abnormalities mean a potential risk for food safety. So for a risk-based meat inspection it is affordable to develop information-systems with real mortality and finding rates and the use of drugs on the farm.     

Associations between farm characteristics in fattening pigs and occurrence of lesions at meat inspection

A revised inspection system for fattening pigs in the EU has been proposed emphasizing the need for a more detailed documentation of the fattening process. It is supposed that the availability of such information enables a discrimination of conspicuous and non-conspicuous lots of fattening pigs delivered to the abattoir allowing for a modified, only visual inspection of non-conspicuous lots. This proposal motivated a study performed in 1996 on about 22,000 pigs, searching, among other things, for first hints on associations between management/farm conditions for fattening pigs and lesions found at meat inspection, which can be used for discrimination. Taking the two lesions 'pneumonia' and 'callous affections of the legs' as examples this contribution demonstrates the use of regression trees to visualize association structures and to develop hypotheses on relations between lesions and farm characteristics. An association of 'callous affections of the legs' with flooring systems is clearly shown in the generated tree. The occurrence of 'pneumonia' seems to be associated with the application of disinfection measures in this data set. However, this result should be interpreted with caution as some problems for data analysis arise because of the low number of farms in this study in relation to the high number and complexity of farm characteristics considered. A further problem is the high variability of daily deliveries within farms that cannot be explained referring to farm characteristics common to all deliveries. As a conclusion data from this study have been useful to develop hypotheses on associations between farm characteristics and lesions at meat inspection. However, there is need for further, more specific studies before such associations can be utilized to discriminate between conspicuous and non-conspicuous lots of fattening pigs.     

Procedures in abattoirs and meat inspection. State of the discussion on the implementation of alternative systems

Results of field studies which were performed in EU member states and which dealt with meat inspection procedures in fattening pigs were reviewed with respect to their contribution to alternative systems of meat inspection. The following was concluded: Inspection ante mortem (monitoring of circumstances at the farm of origin): Data which should be given to the notice of the authorities have not yet been satisfactorily defined and their informative value still is not yet clear The predictive character of information from the farm of origin regarding the health status of the animals (results of meat inspection) is not yet sound enough The technique of ante mortem inspection should be reconsidered also. Meat inspection (monitoring and assessment of lesions): In all studies the compared techniques (visual and official procedure) did not entirely find all lesions, which were supposed to be on the carcasses and organs. This was true in different percentages. The impact on consumer's health from the lesions monitored has to be discussed more thoroughly. The information presently available is not yet sound enough to generate a new practicable system of meat inspection. Further pilot studies are necessary.     

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.     

Environmental and food hygiene aspects of cestode infections of humans]

Cysticercus bovis s. inermis, the larvae phase of Taenia saginata is still widely spread. Many reasons are at the origin thereof, e.g. incomplete destruction of the eggs of Taenia saginata during the waste water purification process and differing meat inspection practises. In an area with the same environmental and animal breeding and fattening conditions a yearly average of 6.49% infestation is found in one slaughterhouse, whilst the yearly average in a neighbouring slaughterhouse is 0.93%. The masseter muscles are the main site of infestation. The meat inspection legislation contributes to the infestation with tape-worms in man because of the weakening of the official inspection procedures.     

Predictability of post mortem abnormalities in shipments of slaughter pigs as an aid for meat inspection

This paper reports on the predictability of post mortem abnormalities in individual deliveries of pigs, shipped from the fattening herd to the slaughterhouse. The percentage of pigs in a delivery having post mortem abnormalities was expressed in a Meat Inspection Index. This index is based on data about relevant abnormalities, weighted on the specific significance of each for meat inspection. It was investigated whether Meat Inspection Indices of previous deliveries of pigs could be used for prediction of indices of future deliveries. Results suggest that the Meat Inspection Index cannot be used in such a predictive capacity, partly because of great variation among individual shipments. However, a Meat Inspection Index could play a role in signalling farms that are likely to deliver pigs with a higher level of abnormalities. More attention could then be paid to animals coming from these herds.     

Preselection of finishing pigs on the farm as an aid for meat inspection.

The ability of pig suppliers to separate pigs with abnormalities from pigs without abnormalities at the end of the finishing period was investigated. Nineteen hundred and seventy-eight pigs, delivered by 22 pig suppliers, were involved in the experiment. The pigs were inspected on the farm by the pig supplier and, separately, by a veterinary expert. The animals were sent in 22 deliveries to one slaughterhouse. A veterinary meat inspector carried out the ante- and post-mortem inspections. The results of the inspections were compared. The measure of agreement, Cohen's Kappa (CK), indicated a poor (CK less than 0.40) to fair (0.40 less than CK less than 0.75) agreement among the results of the different inspection procedures, depending on the abnormality under investigation. There was a fair to good agreement for the abnormality 'tail lesion' among all inspections. Some findings of the live animal, such as 'straggler', were associated with a wide range of post-mortem abnormalities. It is concluded that preselection is possible and that the economic and practical feasibility of preselection should be investigated.     

Impact of the Salmonella status of market-age pigs and the pre-slaughter process on Salmonella caecal contamination at slaughter

The aim of this study was to evaluate the impact of the pre-slaughter process on Salmonella caecal contamination of pigs at slaughter. An observational study was carried out in 2001 on 101 conventional farrow-to-finish pig farms. On each farm, one batch of contemporary pigs was followed from the end of the fattening period until slaughter. The Salmonella bacteriological status of the batches was assessed by environmental samples of faecal material. The serological Salmonella status was obtained on 30 individually identified market-age pigs using an indirect ELISA test. At the slaughterhouse, 25 g of caecal contents were taken from 10 of the identified pigs. Faecal and caecal material were analysed according to a classical bacteriological method. A questionnaire was designed to obtain information about the type of feeding during the fattening period (dry versus wet), the duration of fasting on the farm before leaving for the slaughterhouse, the duration of transport between the farm and the slaughterhouse, the holding time in lairage at the slaughterhouse and loading and unloading conditions on the farm and at the slaughterhouse. To assess the relationships between these factors and the Salmonella caecal status of the pigs and the batches, two logistic models were fitted at the individual and at the batch level, respectively. The first analysis was performed using a random effects logistic regression model. The second analysis was based on a cumulative logit model with a positive caecal rate classified into three classes as the outcome variable. The results showed that the Salmonella status of market-age pigs assessed on the farm either by serological or bacteriological examinations and the time spent in lairage before slaughtering played a crucial role on caecal contamination. In the light of these results, actions should be considered both on the farm and at the slaughterhouse to decrease the risk of Salmonella contamination of the caecal contents.     

Preselection of finishing pigs on the farm as an aid for meat inspection

Summary

The ability of pig suppliers to separate pigs with abnormalities from pigs without abnormalities at the end of the finishing period was investigated Nineteen hundred and seventy‐eight pigs, delivered by 22 pig suppliers, were involved in the experiment The pigs were inspected on the farm by the pig supplier and separately, by a veterinary expert The animals were sent in 22 deliveries to one slaughterhouse. A veterinary meat inspector carried out the ante‐ and post‐mortem inspections. The results of the inspections were compared The measure of agreement, Cohen's Kappa (CK), indicated a poor (CK < 0.40) to fair (0.40 < CK < 0.75) agreement among the results of the different inspection procedures, depending on the abnormality under investigation. There was a fair to good agreement for the abnormality ‘tail lesion’ among all inspections. Some findings of the live animal, such as ‘straggler’, were associated with a wide range of post‐mortem abnormalities. It is concluded that preselection is possible and that the economic and practical feasibility of preselection should be investigated.     

Use of information from pig finishing herds for meat inspection purposes.

In a field trial on Integrated Quality Control of finishing pigs we evaluated information written on Quality Information Cards (QUIC) for meat inspection purposes. These cards were sent with 3747 shipments of pigs going from the finishing herd to the slaughterhouse. Pig suppliers answered five questions dealing with health problems and the use of drugs during the finishing period. By comparing QUIC answers to recorded post-mortem abnormalities, we found that the information on the QUIC had some, albeit low, predictive value with respect to the abnormalities 'arthritis', 'condemned liver' and lung lesions. Shipments without a QUIC or with a faulty QUIC were considered 'suspect' because higher levels of abnormalities were found in these shipments. These results indicate the potential use of a QUIC.     

Future role of the official veterinarian at the ante- and post-mortem inspection

The new European food hygiene legislation which will apply from 1 January 2006 on brings massive changes in the implementation of the ante- and post-mortem in-spection about. Key element in this new regulation is the introduction of a risk-based inspection of graduated intensity which in particular cases may be reduced to a document check and a visual inspection. Important changes also concern responsibility assignment between official veterinarian and official auxiliary in inspection tasks. Furthermore, the official veterinarian is assigned additional responsibility (animal welfare, animal health check). Regarding the extended competence of the official auxiliaries through the new regulation, food industry is requiring a diminution of the inspection costs. In this article, the future scope of duties of the official veterinarian at the ante- and post-mortem inspection is presented, as well as the practical consequences the implementation of the new meat hygiene regulation will have.     

Use of information from Pig finishing herds for meat inspection purposes

Summary

In a field trial on Integrated Quality Control of finishing pigs we evaluated information written on Quality Information Cards (QUIC) for meat inspection purposes. These cards were sent with 3747 shipments of pigs going from the finishing herd to the slaughterhouse. Pig suppliers answered five questions dealing with health problems and the use of drugs during the finishing period By comparing QUIC answers to recorded post‐mortem abnormalities, we found that the information on the QUIC had some, albeit low, predictive value with respect to the abnormalities ‘arthritis’, ‘condemned liver’ and lung lesions. Shipments without a QUIC or with a faulty QUIC were considered ‘suspect’ because higher levels of abnormalities were found in these shipments. These results indicate the potential use of a QUIC.     

Physiological indicators of stress and meat and carcass characteristics in tail bitten slaughter pigs

Background

Tail biting is a common welfare problem in pig production and in addition to being a sign of underlying welfare problems, tail biting reduces welfare in itself. The aim of this study was to evaluate the effects of tail biting on different pre and post mortem indicators of stress in slaughter pigs and on carcass and meat characteristics. A total of 12 tail bitten (TB) and 13 control (C) pigs from a farm with a long-term tail biting problem were selected for salivary cortisol analyses before and after transport to the slaughterhouse. After stunning, samples were taken for the analysis of serum cortisol, blood lactate, intestinal heat shock protein 70 (HSP70), and meat quality characteristics. In addition, body temperature immediately after and muscle temperature 35 min after stunning were measured, as well as lean meat percentage and carcass weight.

Results

TB pigs showed a lower cortisol response to the transport-induced stress than C pigs and also had a lower serum cortisol concentration after stunning. HSP70 content in the small intestine was higher in the TB pigs than in C pigs. TB pigs had a considerably lower carcass weight therefore produced a lower total amount of lean meat per carcass than C pigs.

Conclusions

This study suggests that prolonged or repeated stress in the form of tail biting causes a blunted stress response, possibly a sign of hypocortisolism. In addition, it underlines the importance of reducing tail biting, both from an animal welfare and an economic point-of-view.     

Meat Juice Serology and Improved Food Chain Information as Control Tools for Pork‐Related Public Health Hazards

The seroprevalence of Salmonella spp., pathogenic Yersinia spp., Toxoplasma gondii and Trichinella spp. was studied in 1353 finishing pigs from 259 farms that were allocated according to farm types: large fattening farms (≥1000 pig places), small fattening farms (< 1000 pig places) and farrow‐to‐finish farms. The antibodies were analysed with commercial ELISA kits in meat juice samples that were collected at Finnish slaughterhouses. Salmonella antibodies were rare (3% of pigs, 14% of farms) when the cut‐off optical density (OD) value 0.2 was used. Antibodies to pathogenic Yersinia spp. and T. gondii were detected in 57% of pigs and 85% of farms (OD ≥0.3) and in 3% of pigs and 9% of farms (OD ≥0.15), respectively. No antibodies to Trichinella spp. were detected (OD ≥0.3). The European Food Safety Authority (EFSA) considers Salmonella spp., Yersinia enterocolitica, T. gondii and Trichinella spp. as the most relevant biological hazards in the context of meat inspection of pigs. The seroprevalence of these important zoonotic pathogens was low in Finland, except that of Yersinia. The seroprevalence of Toxoplasma was significantly higher in pigs originating from small‐scale fattening farms (P < 0.05). Strong positive correlation was observed at the animal level between Salmonella and Yersinia seropositivity and between Salmonella and Toxoplasma seropositivity (P < 0.05). We suggest that these results reflect the level and importance of biosecurity measures applied on the farms. Meat juice serology at slaughter is a useful tool for targeting measures to control these pathogens. The information obtained from analyses should be used as part of the food chain information (FCI).     

A possible approach to improve present meat inspection

The final decision in the meat inspection mainly depends on the results of the examinations before, during, or directly after the slaughter of animals in the slaughterhouse. The present threats to public health cannot be adequately judged on that place and under these circumstances. A new approach of the meat inspection methods is only possible with the cooperation of the other EU member states and the people who are involved in the meat inspection. New views on the purpose of meat inspection and the possibility of translation of these ideas towards Food Safety Objectives could be the basis for adaptation of the meat inspection. The rigid form in which the present meat inspection exists can be changed by this approach.     

Husbandry factors causing morphologic abnormalities in poultry meat (broilers)]

Zootechnical events affect the state of slaughtered poultry. Data from the literature are compiled. From this point of view monitoring of environmental parameters and morphological findings observed in the slaughterhouse can help in detecting faults in the fattening period. An approach like this would contribute to quality control in broiler meat production.     

Parasites in meat: a challenge for veterinarians in meat hygiene

Meat hygiene is an important instrument of preventive public health since the end of the nineteenth century. The methods used during ante-mortem and post-mortem inspection are partly quite traditional. This is in particular true for the identification of parasites in meat. The aim of this review was to present facts on aetiology, prevalence and importance of meat-borne parasitic hazards. The capacity and the limits of the ante-mortem and post-mortem inspection for the identification of parasitic hazards are considered. Further, suggestions for the improvement of the meat hygiene are given. Cysticercosis, Toxoplasmosis and Sarcocystosis are exposed in detail. With regard to Cysticercosis, the integration of serological methods in the inspection procedure could result in a tenfold improvement of diagnostical sensitivity. With regard to Toxoplasmosis, it is obvious that meat containing Toxoplasma-cysts may reach the consumer, as animals infected with Toxoplasma gondii can neither be recognised in the ante-mortem inspection nor in the meat inspection. Systematical serological investigations on farm level would allow an appropriate judgement during meat inspection and minimize the consumer exposure to this parasite. Further, reliable methods for the detection of Toxoplasma-cysts have to be developed. With regard to Sarcocystosis, the compulsory inspection of the muscle surfaces to recognise a "massive infection with Sarcocystis" is very doubtful in its interpretation. There is a need for suitable microscopic, serological and molecular biological methods for the detection of Sarcocystis-species and reliable informations on the seroprevalence of the parasite in slaughtering animals.     

Prevalence and Risk Factors for Bacterial Food‐Borne Zoonotic Hazards in Slaughter Pigs: A Review

The Hygiene Package and Regulation EC‐2160/2003 require information flow from farm to slaughterhouse to enhance European consumers protection in a ‘farm to fork’ approach. This obligation especially concerns food‐borne zoonotic hazards transmitted to humans through pork consumption, such as thermophilic Campylobacter spp., Listeria monocytogenes, Salmonella enterica and Yersinia enterocolitica. Prevalence estimates of these four hazards are affected by the sampling strategy and diagnostic procedure. Individual prevalence estimates for pig carriage (from digestive contents or lymph nodes collected at slaughterhouse) were higher than individual prevalence estimates for pig shedding (from faeces). Among risk factors described in the literature, poor pen cleaning and disinfection after pig departure to slaughterhouse and poor bio‐security measures are of major significance. Moreover, whereas wet feed increases the risk of pig infection by L. monocytogenes, dry feed is a risk factor for Salm. enterica. Mixing batches of pigs, notably in fattening herds, represents a risk for the transmission of Salm. enterica and Y. enterocolitica. Whereas small herds are more infected by thermophilic campylobacters and Y. enterocolitica, higher prevalence of Salmonella is observed in large herds due to a more frequent mixing of batches. Antibiotic treatment during the finishing period increases the risk of transmission of Salm. enterica. The forenamed elements should be taken into account to characterize farms in a risk assessment approach and to improve zoonotic hazard management in the pork food chain.     

Proposals for designing the food chain information for the implementation of the risk-oriented ante- and post-mortem meat inspection

The recent crises in the meat industry due to meat-associated risks such as salmonella, nitrofen and dioxin prove that the traditional ante- and post mortem inspection of slaughter animals and carcasses is not any longer able to recognise and prevent the risks of today. Therefore, the EU Commission has issued Reg. (EC) 853/2004 and Reg. (EC) 854/2004 that regulate the transition of the traditional meat inspection, which demands inspecting each individual carcass in the same way, to a risk-based meat inspection, which is using relevant pieces of information about the previous production stages for making risk-based decisions on the intensity of the inspection of slaughter pig batches. The new EU legislation is not any longer prescribing exactly the inspection procedure, but defines the food safety goals. The consequence is that there are still various ideas and opinions on how to implement a reasonable risk-based meat inspection, and, in particular, on how to design the "relevant food chain information". The present paper is describing the legal framework and the objectives of the risk-based meat inspection, and proposals for designing the food chain information for the implementation of the risk-based ante- and post-mortem meat inspection are made and discussed.     

德氏乳杆菌对育肥猪胴体性状及肉品质的影响

本试验旨在研究无抗生素饲粮中添加德氏乳杆菌对育肥猪胴体性状、肉品质及背最长肌营养成分的影响。试验选用健康、平均体重为(65.34±3.64)kg的"杜×(长×大)"育肥猪120头,随机分为2个组,每组6个重复,每个重复10头猪(公母各占1/2)。对照组饲喂无抗生素基础饲粮,试验组饲喂在无抗生素基础饲粮中添加0.1%德氏乳杆菌的饲粮。试验期42 d。结果表明:2组育肥猪的胴体性状差异不显著(P0.05);与对照组相比,试验组育肥猪的脾重率和胰重率显著升高(P0.05);宰后45 min时2组育肥猪的肉品质差异不显著(P0.05),宰后24 h时,与对照组相比,试验组育肥猪肉的黄度显著升高(P0.05),剪切力显著降低(P0.05);与对照组相比,试验组育肥猪背最长肌中甘氨酸、丙氨酸和风味氨基酸含量显著升高(P0.05),葵酸和棕榈酸含量显著降低(P0.05),棕榈油酸、亚油酸和多不饱和脂肪酸含量显著升高(P0.05)。结果提示,无抗生素饲粮中添加0.1%德氏乳杆菌对育肥猪的胴体性状、肉品质及肉中营养成分具有一定改善作用。