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.     

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.     

An outline of a risk assessment-based system of meat safety assurance and its future prospects

Discussed are the outlines of a risk assessment-based system of meat safety assurance to replace the current meat inspection. An example of a system that uses the Hazard Analysis of Critical Control Points (HACCP)-principles in the entire production chain from stable to table is also given. Continuous evaluation of risks is the main driving force of the new system. Only then the system has the means to remain flexible and provide for the data necessary to convince trade partners that the products they buy are safe. A monitoring system that keeps track of the important health hazards in the entire chain from stable to table is therefore necessary. This includes monitoring of cases of disease in the human population caused by the hazardous agents of concern. Coordination of the monitoring and control and processing of the information is done by an independent body. Furthermore, the system demands a production from stable to table that is based on the ideas of Integrated Quality Control (IQC), HACCP, and certification of production processes and quality control procedures. Clear legislation provides for criteria about acceptable or unacceptable health risks for the consumer and determines at what moments which risks should be controlled by the producers. Simultaneously, the legislation has to be flexible enough to be able to adapt quickly to any changes in risks, or in the way risks should be controlled. In the new system current meat inspection can easily be carried out by employees of the slaughter houses and is no longer a direct responsibility of the authorities. The authorities only demand certain safety levels and verify whether producers stick to these. Producers remain fully responsible for the safety and quality of their products, and fully liable in case of any damage to the consumers' health. However, it is to be expected that some EU Member-States miss the organizational and agricultural basis for a successful application of the new system. Consequences are that two parallel flows of meat and meat products may come to existence. One flow will exist of meat produced according to the new, and with respect to safety assurance, superior system. The other flow will consist of meat produced and inspected in the traditional way. However, this meat will contain all the flaws that required a revision of the system in the first place. This, and the fact that EU policy ordains that part-taking in an alternative meat inspection system should be voluntary, may very well result in a very slow start-up of the new system. One of the easiest solutions, however, would be to implement a decontamination step in the slaughtering process, provided that this is accompanied by strict codes of hygienic practices and good manufacturing practices. Not only would this lead to safer meat, but also result in the two separate flows of meat becoming one flow again as well as an easier to organize livestock production according to HACCP-principles.     

Evaluation of the antibacterial residue surveillance programme in Danish pigs using Bayesian methods

Residues of pharmacological active substances or their metabolites might be found in food products from food-producing animals. Maximum Residue Limits for pharmacological active substances in foodstuffs of animal origin are established to assure high food safety standards. Each year, more than 20,000 samples are analysed for the presence of antibacterial residues in Danish pigs. This corresponds to 0.1% of the size of the slaughter pig population and more than 1% of the sows slaughtered. In this study, a Bayesian model was used to evaluate the Danish surveillance system accuracy and to investigate the impact of a potential risk-based sampling approach to the residue surveillance programme in Danish slaughter pigs. Danish surveillance data from 2005 to 2009 and limited knowledge about true prevalence and test sensitivity and specificity were included in the model. According to the model, the true antibacterial residue prevalence in Danish pigs is very low in both sows (～0.20%) and slaughter pigs (～0.01%). Despite data constraints, the results suggest that the current screening test used in Denmark presents high sensitivity (85-99%) and very high specificity (>99%) for the most relevant antibacterial classes used in Danish pigs. If high-risk slaughter pigs could be identified by taking into account antibacterial use or meat inspection risk factors, a potential risk-based sampling approach to antibacterial residue surveillance in slaughter pigs would allow reducing the sample size substantially, while increasing or maintaining the probability of detection. Hence, the antibacterial residue surveillance programme in Danish pigs would be more cost-effective than today.     

Meat inspection in the Australian red-meat industries: past, present and future

Postmortem inspection of carcases and offal has been a cornerstone of consumer protection in the red-meat industry for over a century. In 2011, there began strong moves to reform the traditional process of meat inspection applied to cattle, sheep and goats in Australia. A major motivation was the widespread acceptance that organoleptic inspection does little to control the most important hazards in meat products - microbial pathogens derived from gut flora. The watershed reforms in international trade provided another incentive by encouraging the application of a risk-based approach to food safety, which allows for the discontinuation of processes that do not enhance public health outcomes. As well, there was a strong imperative to ensure that resources allocated to quality assurance delivered maximum economic benefit for both consumers and processors. This review discusses how the role of meat inspection is likely to evolve into the future under the influence of these forces. It summarises how the current system was derived through repeated modification over time, mainly to satisfy the requirements of trading partners. Major developments are summarised, focusing especially on how the inclusion of particular organoleptic techniques was initially justified and the relevance of these to modern meat production. Overall, analysis of past and present practices suggests that in the future both public health and efficiency will be better served by strategically integrating the most effective elements of traditional organoleptic inspection with information from the preslaughter period and the use of modern technology for rapid and accurate detection of hazards.     

A Case–Control Study of Risk Factors for Bovine Cysticercosis in Danish Cattle Herds

Bovine cysticercosis (BC) is a zoonotic, parasitic infection in cattle. Under the current EU meat inspection regulation, every single carcass from all bovines above 6 weeks of age is examined for BC. This method is costly and makes more sense in countries with higher number of BC‐infected animals than in countries with few lightly infected cases per year. The aim of the present case–control study was to quantify associations between potential herd‐level risk factors and BC in Danish cattle herds. Risk factors can be used in the design of a risk‐based meat inspection system targeted towards the animals with the highest risk of BC. Cases (n = 77) included herds that hosted at least one animal diagnosed with BC at meat inspection, from 2006 to 2010. Control herds (n = 231) consisted of randomly selected herds that had not hosted any animals diagnosed with BC between 2004 and 2010. The answers from a questionnaire and register data from the Danish Cattle Database were grouped into meaningful variables and used to investigate the risk factors for BC using a multivariable logistic regression model. Case herds were almost three times more likely than control herds to let all or most animals out grazing. Case herds were more than five times more likely than control herds to allow their animals access to risky water sources with sewage treatment plant effluent in proximity. Case herds were also more likely to share machinery or hire contractors than control herds. The risk decreased with increasing herd size probably because the larger herds generally tend to keep cattle indoors in Denmark. The results are useful to guide future data recording that can be supplied by the farmer as food chain information and then be used for differentiated meat inspection in low‐ and high‐risk groups, enabling development of risk‐based meat inspection systems.     

Risk based meat hygiene--examples on food chain information and visual meat inspection

The Regulation (EC) No. 854/2004 refers in particularly to a broad spectrum of official supervision of products of animal origin. The supervision should be based on the most current relevant information which is available. The proposal presented includes forms for implementation of Food Chain Information (FCI) as laid down in the Regulation (EC) No. 853/2004 as well as suggestions for the implementation of the visual inspection and criteria for a practical approach to assist the competent authority and the business operator. These suggestions are summarised in two forms including the FCI and practical information from the farm of origin as well as from the slaughterhouse needed for the competent authority to permit the visual meat inspection of fattening pigs. The requested information from the farm level include i.e. an animal loss rate during the fattening period and diagnostic findings of carcasses and respectively on organs of the animals during meat inspection procedure. The evaluation of findings in liver and pleura at the slaughterhouse level indicate a correlation to the general health status of the fattening conditions at farm level. The criteria developed are in principle suited for a "gold standard" of the health status of fattening pigs and the criteria may serve as practical implementation of the term Good Farming Practice in relation to consumer protection. Only for fattening pigs deriving from farms fulfilling this "gold standard" the visual meat inspection shall be permitted. It is proposed to integrate the two forms for FCI and additional information for authorisation of visual meat inspection for fattening pigs in the working document of the DG SANCO titled "Commission regulation of laying down specific rules on official controls for the inspection of meat" (SANCO/2696/2006).     

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.     

Dog slaughtering in Germany in the 19th and 20th centuries with special consideration of the Munich area]

In the 19th century professional dog slaughter and also the public sale of dog flesh arose. These slaughter and the sale was mainly practised by horse butchers. In Germany dogs had been mostly slaughtered in Sachsen, Schlesien, Anhalt and Bayern. From 1905 to 1940 the meat of 235.144 dogs was inspected. But the true number of slaughtered dogs was certainly larger. Yet in the fifties dogs were professionally slaughtered. After 1960 the slaughter dropped. Sporadically dog flesh was used as human food until 1985. The annual number of slaughtered dogs depended on economic factors like wages, prices of meat, availability of meat and dog tax. Dogs had been also slaughtered to produce dog fat for remedy. Slaughter of dogs has been already discussed in the 19th century. After 1930 it was called for abolishing the inspection order for dogs or for the prohibition of dog slaughter. After four bills of the years 1954, 1963 and 1985 the slaughter of dogs to produce human food was finally prohibited in 1986.     

The need for built-in validation of surveillance data so that changes in diagnostic performance of post-mortem meat inspection can be detected

Time trends in animal-disease surveillance often are evaluated on the basis of crude estimates of apparent prevalence. In addition to possible changes in the true prevalence of the condition, changes in apparent prevalence over time might reflect changes in sensitivity and/or specificity of the diagnostic classification used. To illustrate this, comparative post-mortem meat inspection data from four Danish slaughter plants sampled in 1993-1994 and 1997-1998 were used to obtain latent-class model estimates of the sensitivity and specificity of traditional and extended post-mortem meat inspection of visceral and parietal chronic pleuritis (CP), respectively.True prevalence of CP was estimated for each study period and slaughter plant by latent-class models. Estimated sensitivities of traditional post-mortem meat (TPM) inspection ranged from 28.8 to 61.4% (1993-1994) and 39.2 to 87.3% (1997-1998). An increase in sensitivity with time was seen for all slaughter plants. Estimated sensitivities of extended post-mortem meat (EPM) inspection ranged from 85.7 to 94.8% (1993-1994) and 73.8 to 93.0% (1997-1998). All estimated specificities were >93.3%.The possible association of the estimated true prevalence of CP with time (1993-1994 versus 1997-1998) was investigated with a logistic-regression model with random effects. A slight, but non-significant decrease in the odds of CP from 1994 to 1998 was found (odds ratio=0.9).In this and similar situations, one should consider conducting ongoing double-classification of samples of units followed by statistical estimation of true prevalences, sensitivities and specificities, so that decisions can be based on such estimates rather than on crude apparent prevalences.     

Changes in the EU legislation on Trichinella inspection--new challenges in the epidemiology

The European Union (EU) countries are searching for new ways to certify meat free of Trichinella; however, with the expansion of the EU, the acceptance of a unilateral method is complicated by the variability of pig and human trichinellosis among EU countries, where significantly higher prevalence rates have been observed in the newly added eastern countries. Several attempts have been made to define Trichinella-free areas, but certification of Trichinella-free pig production farms appears to be the only feasible approach. The increasing prevalence of the non-encapsulating species, Trichinella pseudospiralis, in game, domestic pigs and humans has eliminated the compression technique from the new EU legislation to be enacted in 2006. Also, the observation that several species of Trichinella tolerate freezing in horse meat for up to 4 weeks has forced a change in legislation as well where freezing is no longer an option for certifying horse meat. Because current serological detection methods are not suited for meat inspection, classical direct detection methods and inactivation by freezing remain the methods of choice for pork. It has been proposed, therefore, to automate direct inspection methods as a cost effective alternative to certify pig farms free of Trichinella.     

The sylvatic Trichinella cycle and its implications for Trichinella control in Germany

Trichinellosis is a food-borne, zoonotic disease caused by a parasitic organism. Pork containing muscle larvae represents the most important source of human trichinellosis. In Germany, each slaughtered domestic swine is systematically sampled and examined for Trichinella spp. European Union legislation (EC (No.) 2075/2005) condones the approach of a risk-oriented meat inspection for Trichinella in pigs which is accompanied by monitoring programmes for pig holdings and reservoir animals. Here we discuss the current epidemiological situation of Trichinella in the sylvatic cycle in Germany and the implications for the implementation of risk-based sampling.     

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.     

Establishment of serological herd profiles for zoonoses and production diseases in pigs by “meat juice multi-serology”

The most important pork-borne zoonotic diseases in humans such as Salmonelloses and Yersinioses cause only latent infections in pigs. Thus, the infection of pigs does not result in apparent or palpable alterations in the pig carcasses. This is the major reason, why the traditional meat inspection with adspection, palpation and incision is not able to control the food safety risks of today. The objective of this paper is to evaluate a set of serological tests, which provides a classification of pig herds into “zoonoses risk categories” as demanded by EU law and into “herd health risk categories” by using meat juice as diagnostic specimen for ELISA tests. Serological data that were obtained by testing meat juice samples from various pig herds were analyzed as proof of the “meat juice multi-serology” concept. For that, at least 60 meat juice samples from 49 pig herds each were taken between September 2010 and March 2011 and tested for antibodies against zoonotic pathogens (Salmonella spp., Trichinella spp., Yersinia enterocolitica and Toxoplasma gondii) and against pathogens causing production diseases (Mycoplasma hyopneumoniae, influenza A virus subtype H1N1, influenza A virus subtype H3N2 and PRRSV). Apparent and true animal prevalence, herd prevalence values and intra-herd seroprevalence values as well as the predictive values for the herd and the animal prevalence values were calculated for each pathogen and each of the 49 randomly selected herds. The herd seroprevalence values (one seropositive sample per herd determined a “positive herd”) for Y. enterocolitica, Salmonella spp., T. gondii, M. hyopneumoniae and PRRSV were higher than 80%, respectively, for the influenza A viruses between 60% and 14% and for Trichinella spp. 0%. Although all herds were located in the same area in the Northwest of Germany within a radius of 250 km, the intra-herd seroprevalence values for all tested pathogens, except for Trichinella spp., varied remarkably from herd to herd. In the case of Y. enterocolitica and T. gondii the intra-herd seroprevalence values varied even from zero to 100%. This shows that a serological risk categorization of pig herds regarding zoonoses and production diseases is meaningful if used for risk-based decisions in the framework of the new meat inspection concept and as part of the herd health management system. Thus, the development of a cost-efficient, time- and labour-saving test system for simultaneously detecting various antibodies should be the next step for an extensive implementation of the meat juice multi-serology concept.     

Methods for investigating Trichinella infections in domestic and wild animals

Trichinellosis is an important parasitic zoonosis that is caused by the intracellular nematode Trichinella spp.. Infection of humans occurs through consumption of raw (or undercooked) meat containing infectious larvae. In Europe, meat from pork, horse, and wild boar have been identified as most important sources of Trichinella infections in humans. In Switzerland, both the domestic pig and wild boar population are considered free of Trichinella. Conversely, Swiss foxes, lynxs and recently a wolf were found to be infected, the species identified in these animals was always referred to as Trichinella britovi. Although this species rarely infects pork and, compared to Trichinella spiralis, only causes reduced pathogenic effects in humans, the basic presence of Trichinella in Switzerland cannot be neglegted. This fact has gained increasing importance since the responsible authorities in the European Union (EU) are preparing regulations for the official Trichinella-control in meat in order to improve food safety for consumers. These regulations will be implemented as a consequence of the recent association of east European countries with the EU. This new legislation particularly takes into account, that in the past by far most cases of human trichinellosis in the EU were due to consumption of imported east European meat.Within the framework of the bilateral agreements of Switzerland with the EU, the Swiss veterinary public health authorities will have to comply with the foreseen EU regulations. Although diagnostic methods for the direct demonstation of Trichinella in pork meat are already routine practice in several Swiss abattoirs, the implementation of a meat control program for Trichinella for the entire slaughter pig population of the country would lead to an enormous increase in costs for the administration and will require an increased infrastructure in veterinary services. In order to find a reduced testing format for monitoring Trichinella infections in Swiss pork, an infection risk-oriented survey strategy is currently evaluated. In the present article, this minimized survey strategy is discussed regarding its compatibility with the EU regulations laying down rules for the official control of meat for Trichinella.     

Straussenhaltung in Deutschland / Straussenfleisch aus Namibia--ein Fallbeispiel. [Ostrich husbandry in Germany / ostrich meat from Namibia - a case study]

Within the European Union, academic professions themselves are expected to reach a comparable level of professionalism, a fact that veterinary medicine as well should not ignore. At present, a working group is developing a concept of a teaching module for the Socrates programme "Education in Veterinary Public Health (VPH)", enabling the students by "case studies" to be induced to an integrated approach of tackling problems. In an attempt to demonstrate the didactic procedure, a study of ostrich meat as food for human consumption is presented as a concrete example. In the detailed teacher's guide, informations are given about ostrich husbandry, slaughter procedure and meat inspection, as well as detailed explanations how the health of human consumer can be safeguarded by the introduction of the HACCP system.     

Meat inspection in New Zealand: prospects for change

Regulatory authorities are facing increasing challenges with respect to the newly-recognised public health risks associated with meat products. Meat inspection resources should be allocated according to their maximum ability to reduce food-borne hazards, rather than according to the classical rules of meat inspection. Scientific evaluation of routine post-mortem inspection procedures for each class of livestock, introduction of the Hazard Analysis Critical Control Point approach to process control, on-line testing for microbiological hazards and residues, and effective management of production, processing and inspection data are central to this process. The meat inspection system that has evolved in New Zealand reflects a response to non-scientific forces such as market requirements and industrial practices rather than scientific discipline. In the future, the daily routine of meat inspectors will be extended well beyond their current slaughterfloor responsibilities, and veterinarians will require specialist skills. Science should be the basis for international food regulation and policy concepts such as equivalence or mutual acceptance are achievable on this basis.     

Food safety achieved through herd management

Most animal-derived food products originate from production chains consisting of a series of well-defined, separate production steps. Undesired events affecting food safety can principally occur at any point within the production chain. The principle of integrated food safety assurance from stable to table has therefore been established. The livestock holding has thus to be understood as a fix element of the production chain, and the producer has to accept a part of the responsibility for food safety. On a farm, food safety can be negatively affected by animal feed (microbiological or toxicological contamination), management (hygiene, stocking density, cleaning and disinfecting), veterinary treatments (use of antibiotics) and recycling of slurry. Most relevant practices can be summarised under the standard of "good farming practice". HACCP programmes as they are applied in the processing industries could in principle also be used at the farm level. Influential management steps would need to be identified and controlled. This approach is, however, still in its infancy at present. Using the current monitoring systems, microbiological and toxicological problems in food are difficult to be identified before the end of the production chain. As the cause of a problem can be found at the farm level, traceability of products through the production chain is essential. In Switzerland, traceability of animals is realised using compulsory animal identification and the animal movement database. Using this link, information on the health status of a herd could be made available to the slaughterhouse in order to classify animals into food-safety risk categories. This principle is a key element in the ongoing discussion about visual meat inspection in Europe and elsewhere.     

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.     

Combination of variance components estimation, regression trees and logistic regression as a concept for exploring associations between animal husbandry conditions and lesions found at slaughter

Integrated quality control measures have been discussed in farm animal husbandry and veterinary medicine for some time in search of concepts to link information on management factors with disease data gained by veterinary meat inspection at slaughter. Better understanding of relationships between these variables hopefully will help to improve management practices as well as meat quality and safety. In order to analyse data gained on-farm and at slaugherhouses and to investigate relationships between animal husbandry conditions and lesion occurrence at slaughter a biometrical concept has been developed. This concept combines a characterization of variation structures, the generation of regression trees to explore association structures in available animal management and disease data, and logistic regression used to quantify systematic effects of farm management factors. The combination of these three steps is illustrated with an example.