Implementation of Visual-Only Swine Inspection in the European Union: Challenges, Opportunities, and Lessons Learned

Meat Inspection Decisions Regarding Pig Carcasses Affected by Osteomyelitis at the Slaughterhouse: From Etiopathogenesis to Total Condemnation Criteria

Osteomyelitis is a significant cause of total carcass condemnation in pigs at the slaughterhouse. The decision for total condemnation of a pig carcass for osteomyelitis is often based on traditional perceptions of the risk of pyaemia, leading to controversy among Official Veterinarians (OV) in the industry. This review aims to provide a more comprehensive understanding of the etiopathogenesis of osteomyelitis in pigs, the microorganisms involved, and the risk factors. It also highlights the urgent need for a more uniform method to evaluate osteomyelitis cases, which could significantly reduce economic losses in the industry. Lesions originating from tail-biting, tail docking, castration, teeth resection, and raw management are described as risk factors for osteomyelitis. Osteomyelitis is caused by the entry of pathogens into the animal's bloodstream through an open wound. Trueperella monocytogenes, Staphylococcus aureus, and Streptococcus spp. are the most described pathogens. At slaughter, OVs condemn carcasses with osteomyelitis due to pyaemia. Signs of acute disease are essential to identify pyaemia cases. In chronic cases, total carcass condemnation can be avoided depending on the number of lesions and vertebrae affected. A clear overall image of the problem would help authorities in various countries adopt a more homogenous approach.

Scoring Enzootic Pneumonia-like Lesions in Slaughtered Pigs: Traditional vs. Artificial-Intelligence-Based Methods

Artificial-intelligence-based methods are regularly used in the biomedical sciences, mainly in the field of diagnostic imaging. Recently, convolutional neural networks have been trained to score pleurisy and pneumonia in slaughtered pigs. The aim of this study is to further evaluate the performance of a convolutional neural network when compared with the gold standard (i.e., scores provided by a skilled operator along the slaughter chain through visual inspection and palpation). In total, 441 lungs (180 healthy and 261 diseased) are included in this study. Each lung was scored according to traditional methods, which represent the gold standard (Madec's and Christensen's grids). Moreover, the same lungs were photographed and thereafter scored by a trained convolutional neural network. Overall, the results reveal that the convolutional neural network is very specific (95.55%) and quite sensitive (85.05%), showing a rather high correlation when compared with the scores provided by a skilled veterinarian (Spearman's coefficient = 0.831, p < 0.01). In summary, this study suggests that convolutional neural networks could be effectively used at slaughterhouses and stimulates further investigation in this field of research.

Comparing Visual-Only and Visual-Palpation Post-Mortem Lung Scoring Systems in Slaughtering Pigs

Respiratory diseases continue to pose significant challenges in pig production, and the assessment of lung lesions at the abattoir can provide valuable data for epidemiological investigations and disease surveillance. The evaluation of lung lesions at slaughter is a relatively simple, fast, and straightforward process but variations arising from different abattoirs, observers, and scoring methods can introduce uncertainty; moreover, the presence of multiple scoring systems complicates the comparisons of different studies, and currently, there are limited studies that compare these systems among each other. The objective of this study was to compare validated, simplified, and standardized schemes for assessing surface-related lung lesions in slaughtered pigs and analyze their reliability under field conditions. This study was conducted in a high-throughput abattoir in Italy, where two different scoring methods (Madec and Blaha) were benchmarked using 637 plucks. Statistical analysis revealed a good agreement between the two methods when severe or medium lesions were observed; however, their ability to accurately identify healthy lungs and minor injuries diverged significantly. These findings demonstrate that the Blaha method is more suitable for routine surveillance of swine respiratory diseases, whereas the Madec method can give more detailed and reliable results for the respiratory and welfare status of the animals at the farm level.

Condemnation of Porcine Carcasses: A Two-Year Long Survey in an Italian High-Throughput Slaughterhouse

Ante-mortem and post-mortem inspection at slaughter are performed by Official Veterinarians and it is essential to identify alterations/lesions, which can make organs/carcasses unsuitable for human consumption. Obviously, carcass condemnation must be regarded as a highly undesirable event for the entire swine industry chain, as it represents the total failure of a long period of challenging work. Therefore, it seems valuable to estimate the prevalence and causes of carcasses condemnation, in order to preserve consumers' health and pig farming profitability. Bearing that in mind, the present study aimed at providing a reliable picture of the condemnation of porcine carcasses in Italy, with a special emphasis being placed upon pathological findings. Data were collected in a high-throughput abattoir located in northern Italy, where a total of 2,062,278 pigs were slaughtered during the period of study (2021-2022). Overall, 1362 pigs were considered unfit for slaughtering after ante-mortem inspection, mostly because of death during transportation or in resting pens, after their arrival at the abattoir. Moreover, 2007 carcasses were condemned after post-mortem inspection. The most common causes of condemnation were severe and diffuse peritonitis, disseminated abscesses, jaundice, and erysipelas. In our opinion, the present survey may provide useful and updated information about the condemnation of pig carcasses in Italy. At the same time, it highlights the need to collect data in a more systematic and standardized way, thus making possible their comparison over time and among different geographic areas.

Ante-mortem and Post-mortem Inspection and Relationship between Findings in a North Albanian Pig Slaughterhouse

In June 2014, Albania was granted EU candidate status, thus starting a process of compliance with the membership criteria. In this context, a modern meat inspection approach in line with the European legislation was applied to a pig slaughterhouse in northern Albania in order to investigate the ante-mortem (AM) and post-mortem (PM) conditions and the relationship between these findings. For this purpose, 3930 pigs divided into 35 batches were evaluated over a 3-month period. The most frequent AM conditions recorded were tail lesions and dyspnea (9.1%), followed by skin (8.9%) and ear lesions (8.5%), while in the PM inspections, pleuritis was the most frequently observed condition (10.2%), followed by pneumonia (8.5%), liver alterations (5.7%), milk spot liver (3.8%), and pericarditis (3.3%). With the exception of liver alterations, the other PM lesions mentioned were positively associated with lesions on the ears (OR = 1.036; p < 0.001) and skin (OR = 1.026; p = 0.011) and dyspnea (OR = 1.021; p = 0.005), confirming the link between these variables and the health and welfare conditions of pigs on farms. Overall, the evidence that emerged from this Albanian slaughterhouse can be considered in line with other European contexts, especially in light of the considerable variability in the data present in the literature.

The Importance of the Slaughterhouse in Surveilling Animal and Public Health: A Systematic Review

From the point of public health, the objective of the slaughterhouse is to guarantee the safety of meat in which meat inspection represent an essential tool to control animal diseases and guarantee the public health. The slaughterhouse can be used as surveillance center for livestock diseases. However, other aspects related with animal and human health, such as epidemiology and disease control in primary production, control of animal welfare on the farm, surveillance of zoonotic agents responsible for food poisoning, as well as surveillance and control of antimicrobial resistance, can be monitored. These controls should not be seen as a last defensive barrier but rather as a complement to the controls carried out on the farm. Regarding the control of diseases in livestock, scientific research is scarce and outdated, not taking advantage of the potential for disease control. Animal welfare in primary production and during transport can be monitored throughout ante-mortem and post-mortem inspection at the slaughterhouse, providing valuable individual data on animal welfare. Surveillance and research regarding antimicrobial resistance (AMR) at slaughterhouses is scarce, mainly in cattle, sheep, and goats. However, most of the zoonotic pathogens are sensitive to the antibiotics studied. Moreover, the prevalence at the slaughterhouse of zoonotic and foodborne agents seems to be low, but a lack of harmonization in terms of control and communication may lead to underestimate its real prevalence.

Microbiological Quality of Pig Carcasses in a Slaughterhouse under Risk-Based Inspection System

Meat product inspection is one of the procedures adopted more than a century ago to guarantee food quality and safety for consumption. Due to technology and regulation advancement for farming and slaughtering pigs, a change in zoonotic profile attributed to pork has been identified. Thus, a global movement began to establish inspection parameters based on epidemiological risk profiles, culminating in the publication of a new regulation in Brazil in 2018. This normative instruction establishes that slaughterhouses under federal inspection must implement risk-based inspection until 2028. Changes in the inspection system can generate questions and objections on the part of customers and consumer markets. In order to assess microbiological contamination when adopting a risk-based inspection system, the occurrence of Salmonella spp. and the quantification of Enterobacteriaceae and mesophilic aerobic counts were compared in pig carcasses slaughtered under traditional and risk-based inspection systems. A statistical significance reduction was identified regarding the quantification of Enterobacteriaceae (log -0.18 to -1.61 CFU/cm2) and mesophilic aerobic counts (log 4.60 to 3.49 CFU/cm2). The occurrence of Salmonella spp. did not show a significant difference (4% to 5.3%). The results allowed us to conclude that adopting risk-based inspection systems improves food safety through Enterobacteriaceae and mesophilic aerobic counts reduction.

Hygiene Indicators and Salmonellae on Surfaces of Swine Carcasses from Two Slaughterhouses in Northern Portugal

ABSTRACT

The monitoring of carcass surface contamination along the slaughter line enables verification of slaughter operation hygiene and the use of good manufacturing practices. Pork meat is a common source of human nontyphoidal salmonellosis, one of the most frequently reported foodborne illnesses worldwide. This study was conducted to gather data on microbial loads before and after evisceration on the surfaces of swine carcasses in two slaughterhouses. The presence of Salmonella enterica was evaluated only after evisceration on carcass surfaces and in livers and floor drains (environmental samples) because pigs are common carriers of this pathogen. The contamination of carcass surfaces was evaluated by delimitation of surface area with sterilized templates (100 cm2), and surface samples were collected with gauze swabs. Total aerobic mesophilic bacteria, Enterobacteriaceae, and Escherichia coli were enumerated. Significant differences (P < 0.05) in counts of mesophilic bacteria, Enterobacteriaceae, and E. coli were found on the external carcass surfaces, with higher counts after evisceration. The neck and abdominal areas had higher levels of mesophilic bacteria, Enterobacteriaceae, and E. coli and a high prevalence of Salmonella. Salmonella was detected in only one of the studied slaughterhouses; 19 (7.3%) of 259 analyzed carcass samples were positive for Salmonella, and Salmonella was detected in two livers and two floor drains. A total of 52 Salmonella isolates (44 from carcasses, 5 from livers, and 3 from drains) were recovered. Three Salmonella serovars (Typhimurium 4,5:i- , Wernigerone, and Derby) were identified, and 53.8% of the 52 isolates were multidrug resistant. The results reveal the need for continuous improvement of slaughtering operations and implementation of good manufacturing practices to ensure the safety of pork produced in Portugal.

HIGHLIGHTS

Additional post-mortem inspection procedures and laboratory methods as supplements for visual meat inspection of finishing pigs in Europe—Use and variability

In the EU, a post-mortem inspection of finishing pigs comprises visual inspections of the carcass and offal followed by additional examinations, such as palpation and incision of parts, when needed. Moreover, it can include various laboratory tests. Since European meat inspection is regulated by the EU, one may assume that post-mortem inspection is performed in the same way in the Member States. However, previous studies showed that variations exist. This article shows the results of a survey performed in September 2020 on how visual meat inspection of finishing pigs is applied in Europe. By using a questionnaire, palpations, incisions and other procedures for 10 gross pathological findings and laboratory methods applied by official veterinarians to evaluate the fitness of meat for human consumption were assessed. We received 44 responses from 26 European countries. Most respondents reported that visual meat inspection was a generally applied inspection method. The main reason for not applying visual meat inspection was export requirements. The most important reasons for applying palpations and incisions in addition to visual inspection were findings detected in ante- or post-mortem inspection. There was considerable variation in the use of palpations and incisions, other post-mortem procedures and laboratory tests to assess meat fitness for human consumption. The respondents mentioned some country-specific practices, but we also observed variations within the responding official veterinarians that could not be explained by country of origin or years of work experience. Additional detailed studies on the variation are needed before harmonisation of meat inspection procedures are attempted.

Predictivity of Antemortem Findings on Postmortem Inspection in Italian Heavy Pigs Slaughterhouses

Simple Summary

Inspections of pigs before (antemortem) and after (postmortem) being slaughtered are part of the official controls carried out in European abattoirs. The ability of data obtained from the antemortem inspections to predict lesions eventually found during postmortem inspections has not been thoroughly investigated so far. In this study, data obtained from inspections performed both ante- and postmortem in heavy pigs slaughtered in Italy were analyzed, determining the prevalence of the most common lesions and conditions found during the ante- and postmortem inspections and exploring the correlation between these findings. The most common findings were the presence of manure on more than the 30% of the body and pleurisy for antemortem and postmortem inspections, respectively. Some conditions found during the antemortem inspections were predictive of lesions reported during postmortem inspections. For instance, respiratory and kidney lesions were more likely to occur in pigs presenting manure on more than the 30% of the body, whereas dermatitis and skin wounds were more likely to be present in pigs showing skin lesions during the antemortem inspections. The results of this study show that information obtained from the antemortem inspection of pigs can be useful to characterize farms using a risk-based approach and to address the organization of official controls in slaughterhouses.

Abstract

Pigs slaughtered in European abattoirs must be submitted to antemortem inspection (AMI) and postmortem inspection (PMI), as required by the current European legislation in the matter of official controls. AMI and PMI are equally essential to guarantee food safety and to monitor swine health and welfare. However, little is known about the ability of AMI to predict conditions that are possibly found during PMI. In this study, such a correlation was explored together with the assessment of conditions typically found during AMI and PMI in heavy pigs slaughtered in two Italian slaughterhouses. An assessment scheme containing 13 variables for AMI and 34 lesions for PMI was used for the scope. The herd size was also considered as a variable and included in the study. A total of 24,510 pigs and 30,961 pigs were assessed during AMI and PMI, respectively. The most common conditions found were manure on the body covering more than 30% of the body (dirt >30%) and pluck lesions (‘pleurisy’, ‘pericarditis’, and ‘pneumonia’) for AMI and PMI, respectively. A significant correlation (p < 0.05) between some antemortem (AM) findings and postmortem (PM) conditions was found. In particular, the AM conditions ‘dirt >30%’and ‘skin lesions’ were positively related with PM conditions ‘skin wounds’ and ‘dermatitis’, while the complexes of respiratory and kidney lesions were predicted only by the condition ‘dirt >30%’. The variable ‘standardized herd size’ was negatively associated with ‘milk spot liver’ and positively associated with ‘arthritis/bursitis’. The results of this study show that findings reported during AMI can potentially be used to predict certain conditions found in pigs at PMI. These data can be useful for the competent authorities in characterizing swine farms using a risk-based approach and in developing systems and specific plans for official controls.

Meat Safety from Farm to Slaughter—Risk-Based Control of Yersinia enterocolitica and Toxoplasma gondii

The implementation of the traditional meat safety control system has significantly contributed to increasing food safety and public health protection. However, several biological hazards have emerged in meat production, requiring a comprehensive approach to their control, as traditional methods of meat inspection at the slaughterhouse are not able to detect them. While national control programs exist for the most important meat-related hazards, similar data are still lacking for certain neglected threats, such as Yersinia enterocolitica or Toxoplasma gondii. The obstacle in controlling these hazards in the meat chain is their presence in latently infected, asymptomatic animals. Their effective control can only be achieved through systematic preventive measures, surveillance or monitoring, and antimicrobial interventions on farms and in slaughterhouses. To establish such a system, it is important to collect all relevant data on hazard-related epidemiological indicators from the meat chain, which should provide relevant guidance for interventions at the harvest and post-harvest stage. The proposed approach is expected to improve the existing system and provide many opportunities to improve food safety and public health.

Modernization of Control of Pathogenic Micro-Organisms in the Food-Chain Requires a Durable Role for Immunoaffinity-Based Detection Methodology-A Review

Food microbiology is deluged by a vastly growing plethora of analytical methods. This review endeavors to color the context into which methodology has to fit and underlines the importance of sampling and sample treatment. The context is that the highest risk of food contamination is through the animal and human fecal route with a majority of foodborne infections originating from sources in mass and domestic kitchens at the end of the food-chain. Containment requires easy-to-use, failsafe, single-use tests giving an overall risk score in situ. Conversely, progressive food-safety systems are relying increasingly on early assessment of batches and groups involving risk-based sampling, monitoring environment and herd/flock health status, and (historic) food-chain information. Accordingly, responsible field laboratories prefer specificity, multi-analyte, and high-throughput procedures. Under certain etiological and epidemiological circumstances, indirect antigen immunoaffinity assays outperform the diagnostic sensitivity and diagnostic specificity of e.g., nucleic acid sequence-based assays. The current bulk of testing involves therefore ante- and post-mortem probing of humoral response to several pathogens. In this review, the inclusion of immunoglobulins against additional invasive micro-organisms indicating the level of hygiene and ergo public health risks in tests is advocated. Immunomagnetic separation, immunochromatography, immunosensor, microsphere array, lab-on-a-chip/disc platforms increasingly in combination with nanotechnologies, are discussed. The heuristic development of portable and ambulant microfluidic devices is intriguing and promising. Tant pis, many new platforms seem unattainable as the industry standard. Comparability of results with those of reference methods hinders the implementation of new technologies. Whatever the scientific and technological excellence and incentives, the decision-maker determines this implementation after weighing mainly costs and business risks.

A Retrospective Study after 10 Years (2010-2019) of Meat Inspection Activity in a Domestic Swine Abattoir in Tuscany: The Slaughterhouse as an Epidemiological Observatory

Simple Summary

Veterinarians belonging to the Health Authorities are responsible for the safety of food of animal origin. The control activities performed at the slaughterhouse comprise inspections before and after slaughtering to verify the health and welfare of the animals and the wholesomeness of the animal products. In this study, data deriving from ten years (2010–2019) of meat inspection activity in a pig slaughterhouse in Tuscany (Italy) were analyzed to investigate the frequencies of death during transport of whole carcass and partial condemnations and their causes. In total 1,246,309 pigs from 8 different regions of Central and Northern Italy were slaughtered. The mortality rate was found to be lower than the threshold internationally recommended to ensure animal welfare and in line with the mortality values reported at the European level. Overalls 372 carcasses were condemned mainly due to erysipelas, generalized jaundice, lipomatous pseudohypertrophy, generalized abscesses, acute or generalized enteritis, and peritonitis. As regards partial condemnations, liver, lungs, and kidney were the most frequently condemned organs. The results of this study describe a non-worrying situation as regards to the investigated aspects and confirm the slaughterhouse as a privileged observation point for monitoring the trend of the main diseases over time, the results of the efforts for their control, and also the compliance with animal welfare standards.

Abstract

The activities performed by the Official Veterinarian at the slaughterhouse represent a useful source of data for the control of issues affecting human and animal health and welfare. This study analyzed the data deriving from ten years (2010–2019) of meat inspection in a pig slaughterhouse in Tuscany (Italy) to investigate the transport mortality rate and the frequencies and main causes of whole carcass and partial condemnations. In total, 1,246,309 pigs were slaughtered from 8 different regions of Central and Northern Italy. Overall, 1153 pigs died during transport (mortality rate 0.09%). Whole carcass condemnation affected 372 carcasses (0.03%), mainly due to erysipelas, generalized jaundice, lipomatous pseudohypertrophy, generalized abscesses, acute or generalized enteritis, and peritonitis. As regards partial condemnations, the liver was the most frequently condemned (~30% of the pigs), followed by lungs (17.3%), heart (6.9%), and kidney (0.9%). The main causes were “milk spot liver” and perihepatitis for the liver; pneumonia and pleurisy for the lungs; pericarditis and polyserositis for the heart; and polycystic kidney and nephritis for kidneys. The results of this study describe a non-worrying situation as regards the investigated aspects and confirm the slaughterhouse as a valid epidemiological observatory for monitoring the trend of the main diseases over time, the results of the efforts for their control, and the compliance with animal welfare standards.