Finnish Food Safety Authority

The present study was designed to identify nine Arcanobacterium phocae strains isolated from cases of mink dermatitis of a single farm in Finland and characterize the strains for epidemiological relationships. All nine strains and previously described A. phocae used for comparative purposes were identified and further characterized phenotypically, by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), by Fourier Transform Infrared Spectroscopy (FT-IR) and genotypically by detection of phocaelysin encoding gene phl with a previously developed loop-mediated isothermal amplification (LAMP) assay and by sequencing 16S rRNA gene and gene phl, the elongation factor tu encoding gene tuf and the β subunit of bacterial RNA polymerase encoding gene rpoB. Genetic relatedness among isolates was determined using whole-genome single nucleotide polymorphism (wgSNP) analysis. The wgSNP results, partly the MALDI-TOF MS and FT-IR analyses and sequencing of the genes, revealed that the nine A. phocae strains recovered from a single farm showed close sequence similarities among each other and differed from previously investigated A. phocae strains isolated from other farms and animals in Finland and from the A. phocae type strain. This indicated a close epidemiological relationship of the A. phocae strains isolated from a single farm and that the nine A. phocae strains of the present study might have developed from a common ancestor.

Commercially processed meat and fish products are common sources of human exposure to chemical food mutagens. In this study, we investigated the mutagenic potential of 20 different commercially processed meat and fish products (7 product types with 2-3 lots of each), along with the presence of four principal polycyclic aromatic hydrocarbons (PAHs) (benzo[a]pyrene [BaP], benzo[b]fluoranthene [BbF], benzo[a]anthracene [BaA] and chrysene [CHR]) in them. Sample extraction was carried out by an accelerated solvent extraction method, while the concentrations of the 4 PAHs were determined by gas chromatography-tandem mass spectrometry (GC-MS/MS). The mutagenic potential of food extracts was assessed by the standard plate incorporation assay (Ames test) using two strains ofSalmonellatyphimurium (TA 100 and TA 98) both in the presence and the absence of metabolic activation (S9-mix). The results show that in the majority of food items investigated, PAH levels were below the limit of quantification (0.78 mu g/kg), except for smoked fish (0.8-15 mu g/kg for the 3 lots), one batch of which even exceeded the maximum limits for both the sum of the 4 PAHs (44 mu g/kg vs. 30 mu g/kg) and BaP (8.2 mu g/kg vs. 5.0 mu g/kg). Furthermore, all three batches of smoked fish were also found to be mutagenic on both strains ofSalmonella, both in the presence and the absence of metabolic activation. Overall, the data from both assays were in a fairly good agreement with one another, suggesting that PAHs are major contributors to mutagenicity of processed food products and the set maximum levels for PAHs are usually protective against food mutagenicity, although food samples harboring PAHs at levels approaching the maximum limits may exhibit mutagenic potential. Since the number of samples investigated was relatively small, further studies are warranted to verify the conclusions.

•Trichinella spiralis prevalence in wildlife is influenced by the domestic cycle.•T. spiralis eradication from domestic habitat reduces prevalence among wildlife.•Spillover from domestic pigs as a source of T. spiralis in wildlife.

BackgroundSeveral species-specific PCR assays, based on a variety of target genes are currently used in the diagnosis of Mycoplasma bovis infections in cattle herds with respiratory diseases and/or mastitis. With this diversity of methods, and the development of new methods and formats, regular performance comparisons are required to ascertain diagnostic quality. The present study compares PCR methods that are currently used in six national veterinary institutes across Europe. Three different sample panels were compiled and analysed to assess the analytical specificity, analytical sensitivity and comparability of the different PCR methods. The results were also compared, when appropriate, to those obtained through isolation by culture. The sensitivity and comparability panels were composed of samples from bronchoalveolar fluids of veal calves, artificially contaminated or naturally infected, and hence the comparison of the different methods included the whole workflow from DNA extraction to PCR analysis.ResultsThe participating laboratories used i) five different DNA extraction methods, ii) seven different real-time and/or end-point PCRs targeting four different genes and iii) six different real-time PCR platforms. Only one commercial kit was assessed; all other PCR assays were in-house tests adapted from published methods. The analytical specificity of the different PCR methods was comparable except for one laboratory where Mycoplasma agalactiae was tested positive. Frequently, weak-positive results with Ct values between 37 and 40 were obtained for non-target Mycoplasma strains. The limit of detection (LOD) varied from 10 to 10(3)CFU/ml to 10(3) and 10(6)CFU/ml for the real-time and end-point assays, respectively. Cultures were also shown to detect concentrations down to 10(2)CFU/ml. Although Ct values showed considerable variation with naturally infected samples, both between laboratories and tests, the final result interpretation of the samples (positive versus negative) was essentially the same between the different laboratories.ConclusionWith a few exceptions, all methods used routinely in the participating laboratories showed comparable performance, which assures the quality of diagnosis, despite the multiplicity of the methods.

The increased popularity of raw milk consumption has created demand for relaxing legislation, despite the risk of contamination by pathogenic bacteria, notably STEC and C. jejuni . However, the epidemiology of these milk-borne pathogens on the herd level is still poorly understood, and data are lacking on the frequency of milk contamination on farms with cattle shedding these bacteria in their feces. This study suggests (i) that STEC contamination in milk can be reduced, but not prevented, by on-farm hygienic measures while fecal shedding is observable, (ii) that milk filters are more suitable sampling targets for monitoring than milk although pathogen detection from both sample matrices may be challenging, and (iii) that STEC and C. jejuni genotypes may persist in cattle herds for several months. The results can be utilized in developing and targeting pathogen monitoring and risk management on the farm level and contributed to the revision of Finnish legislation in 2017.