Two copies of the ail gene found in Yersinia enterocolitica and Yersinia kristensenii

Yersinia enterocolitica is the most common Yersinia species causing foodborne infections in humans. Pathogenic strains carry the chromosomal ail gene, which is essential for bacterial attachment to and invasion into host cells and for serum resistance. This gene is commonly amplified in several PCR assays detecting pathogenic Y. enterocolitica in food samples and discriminating pathogenic isolates from non-pathogenic ones. We have isolated several non-pathogenic ail-positive Yersinia strains from various sources in Finland. For this study, we selected 16 ail-positive Yersinia strains, which were phenotypically and genotypically characterised. Eleven strains were confirmed to belong to Y. enterocolitica and five strains to Yersinia kristensenii using whole-genome alignment, Parsnp and the SNP phylogenetic tree. All Y. enterocolitica strains belonged to non-pathogenic biotype 1A. We found two copies of the ail gene (ail1 and ail2) in all five Y. kristensenii strains and in one Y. enterocolitica biotype 1A strain. All 16 Yersinia strains carried the ail1 gene consisting of three different sequence patterns (A6-A8), which were highly similar with the ail gene found in high-pathogenic Y. enterocolitica biotype 1B strains (A2). The Ail protein encoded by the ail1 gene was highly conserved compared to the Ail protein encoded by the ail2 gene. Multiple sequence alignment of the ail gene and Ail protein were conducted with MAFF. In total, 10 ail sequence variations have been identified, of which 8 conserved ones belonged to the ail1 gene. According to our results, the detection of ail alone is not sufficient to predict the pathogenicity of Yersinia isolates.Peer reviewe

Identification of Yersinia at the Species and Subspecies Levels Is Challenging

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Views of veterinarians and meat inspectors concerning the practical application of visual meat inspection on domestic pigs in Finland

The post-mortem inspection of domestic pigs within the European Union was revised in 2014, primarily to include visual meat inspection of each carcase and offal. Palpations and incisions were removed from routine meat inspection procedures, as they are mostly used to detect pathological lesions caused by organisms irrelevant for public health, and instead can cause cross-contamination of carcases with foodborne pathogens. However, examination of all external surfaces of the carcase and organs, declaration of patho-physiological lesions as unfit for human consumption, and possibility for minimal handling of carcases and offals were held in place. In addition, the European Food Safety Authority suggested that palpation and incisions should be performed outside the slaughter line, but this was not incorporated in the revised legislation. We surveyed in 2014 the opinions of meat inspectors and veterinarians using an online questionnaire to determine what practical measures are required for the visual meat inspection procedure and when meat inspection staff consider additional palpations and incisions necessary. Based on the survey, turning the carcase and organs or technical arrangements such as mirrors were seen necessary to view all external surfaces. In addition, the pluck set cannot be trimmed on the side line. Local lesions, such as abscesses and lesions in the lymph nodes, signs of systemic infection and lymphoma, were the major lesions requiring additional post-mortem meat inspection procedures. Meat inspection personnel raised concerns on the poor quality of food chain information and export requirements demanding palpations and incisions. The efficient use of visual meat inspection requires legislation to better support the implementation and application of it, changes in the slaughter line layout and a possibility to classify incoming pig batches based on their risk.Peer reviewe

Hunted game birds - Carriers of foodborne pathogens

Game birds may carry zoonotic bacteria in their intestines and transmit them to hunters through bird handling or through the handling and consumption of contaminated meat. In this study, the prevalence of foodborne bacteria was screened from game bird faeces and mallard breast meat using PCR. The sampling occurred in southern Finland from August to December during the hunting season. Isolates were characterized by multi-locus sequence typing. Mesophilic aerobic bacteria and Escherichia coli counts were used to assess the microbial contamination of mallard meat. In total, 100 woodpigeon (Columba palumbus), 101 pheasants (Phasianus colchicus), 110 mallards (Anas platyrhynchos), and 30 teals (Anas crecca) were screened during the hunting season. Additionally, 100 mallard breast meat samples were collected. Campylobacter and Listeria were commonly detected in the faeces and Listeria on mallard meat. L. monocytogenes of sequence types associated with human listeriosis were frequently found in game bird faeces and on mallard meat. Good hygiene during game bird handling, storing the game bird meat frozen, and proper heat treatment are important measures to minimize the health risk for hunters and consumers.Peer reviewe

Bacteriological examination in place in five European countries to assess carcass fitness for consumption during meat inspection

In the European Union, bacteriological examination (BE) can be used as a decision support tool for an individual slaughter animal, if a clear decision regarding fitness for human consumption cannot be reached after performing the post-mortem meat inspection at the abattoir. The mandatory use of BE started already in the beginning of 20th century and the methods have since evolved in the different countries using it. Although still in use, discussions have taken place on whether BE is still a useful part of meat inspection. Currently, there is no European consensus regarding how to set up the methods or how to interpret the results. Still, there is a need to avoid unnecessary food waste, while at the same time guaranteeing food safety. In this descriptive study, we mapped the BE methods currently used in five European countries, namely Denmark, Finland, Germany, Italy and the Netherlands. The results show there is considerable variation between the countries regarding the specific analyses, sample matrices and media used. There is also variation in the indications when BE should be performed as well as when the results lead to condemnation. Although the results will be interpreted together with the pathological findings in the carcass, clearly written instructions should be available on how to interpret the results and when to perform condemnation. BE is used more often for cattle than for pigs, and e.g., in Denmark, BE is not used for pigs due to costs. Although BE can still be used to detect animals with a generalised infection at the time of slaughter, other methods that would be easier to standardise and accredit should be developed

Yersinia spp. in Wild Rodents and Shrews in Finland

Yersinia enterocolitica and Yersinia pseudotuberculosis are important zoonotic bacteria causing human enteric yersiniosis commonly reported in Europe. All Y. pseudotuberculosis strains are considered pathogenic, while Y. enterocolitica include both pathogenic and nonpathogenic strains which can be divided into six biotypes (1A, 1B, and 2-5) and about 30 serotypes. The most common types causing yersiniosis in Europe are Y. enterocolitica bioserotypes 4/O:3 and 2/O:9. Strains belonging to biotype 1A are considered as nonpathogenic because they are missing important virulence genes like the attachment-invasion-locus (ail) gene in the chromosome and the virulence plasmid. The role of wild small mammals as a reservoir of enteropathogenic Yersinia spp. is still obscure. In this study, the presence of Yersinia spp. was examined from 1840 wild small mammals, including voles, mice, and shrews, trapped in Finland during a 7-year period. We isolated seven Yersinia species. Y. enterocolitica was the most common species, isolated from 8% of the animals; while most of these isolates represented nonpathogenic biotype 1A, human pathogenic bioserotype 2/O:9 was also isolated from a field vole. Y. pseudotuberculosis of bioserotype 1/O:2 was isolated from two shrews. The ail gene, which is typically only found in the isolates of biotypes 1B and 2-5 associated with yersiniosis, was frequently (23%) detected in the nonpathogenic isolates of biotype 1A and sporadically (6%) in Yersinia kristensenii isolates. Our results suggest that wild small mammals, especially voles, may serve as carriers for ail-positive Y. enterocolitica 1A and Y. kristensenii. We also demonstrate that voles and shrews sporadically excrete pYV-positive Y. enterocolitica 2/O:9 and Y. pseudotuberculosis 1/O:2, respectively, in their feces and, thus, can serve as a contamination source for vegetables by contaminating the soil.Peer reviewe

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.Peer reviewe

A European survey on post-mortem inspection of finishing pigs: Total condemnation criteria to declare meat unfit for human consumption

Meat inspection (MI) is essential to verify compliance with legal requirements related to human and animal health and animal welfare protections. Judgement criteria applied during MI, resulting in condemnation data of importance, among other things, for livestock producers and for benchmarking reasons. However, although the Meat Inspection Regulation sets out judgement criteria, most are generic, favouring flexibility, but also subjectivity. To address the degree of variation on total condemnation (TC) criteria applied during post-mortem inspection (PMI) of finishing pigs, an online survey was prepared aiming to collect this information from several European countries. The focus was on TC criteria regarding the following PMI findings: abscesses, arthritis, cachexia, erysipelas, icterus, Mycobacterium-like lesions, osteomyelitis, peritonitis, pleuritis and pneumonia. From September to November 2020, a total of 44 completed questionnaires were obtained from 26 European countries. The results showed a substantial variation in the TC criteria in place in the participating countries. One of the main reasons for the variability seen in the respondents' reported answers was related to the indicators used to define a generalised condition related to the 10 PMI findings addressed, making harmonisation a chal-lenge and avoiding to draw conclusions when comparing condemnation causes between abattoirs. This implies that it would make sense to look into how a generalised condition can be identified/described and how it should be judged. The results should be used as inspiration towards possible harmonisation, improving decision-making, and permitting comparative analysis between different reports to allow trend analyses and benchmarking.Peer reviewe

EU-Recht und nationale Umsetzungen der Untauglichkeitsgründe beim Schwein: Vergleich europäischer Befundsysteme

Die Fleischuntersuchung und damit zusammenhängend die Schlachtbefundsysteme dienen der Erfassung und Optimierung der Lebensmittelsicherheit und des Verbraucherschutzes, der Tiergesundheit sowie dem Tierwohl. Die Fleischuntersuchung ist immer wieder Neuerungen unterlegen (Blagojevic et al. 2021. Buncic et al. 2019, Riess & Hölzer 2020). Die Regelungen sind europaweit einheitlich festgelegt (EU-Kommission 2019), sodass sowohl bei der Untersuchung als auch bei den Befundsystemen ein Standard garantiert sein sollte. Im Rahmen einer online-Befragung innerhalb des COST Action Networks RIBMINS (Risk-based meat inspection and integrated meat safety assurance; CA18105) zum Vergleich der existierenden Schlachtbefundsysteme innerhalb Europas zeigte sich allerdings, dass zum Teil große Unterschiede zwischen den nationalen Befundsystemen bestehen (Alban et al. 2021, Vieira-Pinto et al. in Bearbeitung). Ziel der vorliegenden Untersuchung war es, die unterschiedlichen nationalen Befundsysteme zu beschreiben und einerseits untereinander sowie andererseits mit den in der VO (EU) 2019/627 (EU-Kommission 2019) vorgegebenen Untauglichkeitsgründen zu vergleichen. Zusätzlich sollte ein Vorschlag einer Harmonisierung der Befunde für Schweine erarbeitet werden

Parallel independent evolution of pathogenicity within the genus Yersinia

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