Fachbereich Veterinärmedizin



    Die Lebensmittelkette beim Schaf:
    Transfer von Zoonoseerregern vom Tier zum Lebensmittel (2015)

    Sharief, Iman (WE 8)
    Berlin: Mensch und Buch Verlag, 2015 — XLIX, 155 Seiten
    ISBN: 978-3-86387-593-0
    URL (Volltext): http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000099445
    Institut für Lebensmittelsicherheit und -hygiene

    Königsweg 69
    14163 Berlin
    +49 30 838 62550

    Abstract / Zusammenfassung

    This study deals with the occurrence of thermophilic Campylobacter, Listeria, Escherichia coli, Yersinia enterocolitica and Salmonella in a sheep slaughterhouse in Brandenburg, Germany. The aim of this study was to investigate, how these zoonotic agents are distributed within the slaughterhouse and the processing line. Simultaneously, an interrelation between slaughterhouse and the relevant sheep farms was to investigate. Investigations were carried out from July 2008 to August 2009. A total of 423 samples was obtained from 14 excursions. 320 samples using excision method at four process positions of the line, five points of the carcass (before depelting, after depelting, after evisceration and at chilling) and 103 environmental swab samples (floor of the lairage stable floor, fleece depelting machine, deposition board of carcasses after removing the fleece, doorknobs as well as wall of the chilling room and knifes) were collected. The excision samples were analysed for Aerobic Plate Count (APC) and Enterobacteriaceae Count (EC) and all samples qualitative for Campylobacter, Listeria, E.coli, Salmonella and Yersinia. Campylobacter and E.coli isolates were characterized by PFGE (Kpn I enzyme) and PCR respectively.

    For excision samples the mean APC (log10 CFU/cm2) was 3.79, the mean EC (log10 CFU/cm2) was 1.58. An increase in the number of bacteria during the process untill chilling was observed (process position 4). The microbiological carriage of the carcasses for APC and EB was significantly different depending upon the process position.
    Zoonotic agents Thermophilic Campylobacter, Listeria spp. and E.coli were identified with an average of 20.1 %, 11.1 % and 60.1 % of all samples respectively. Yersinia enterocolitica and Salmonella were not found in any sample here. Campylobacter was detected in 20.1 % (85 of 423) by conventional technique, the highest detection rate was obtained in samples from lairage stable floor samples (68.2 %). Campylobacter was not detected in sterilisation bassins, at doorknobs or on the walls in the chilling room. The highest findings on the carcasses was in the chilling room (27.5 %) (process position 4). The Campylobacter isolates were differentiated using conventional and PCR technique: C. jejuni (71.3 % / 55.7 %), C.coli (23.8 % / 11.4%) and C.lari (5.0 % / 14.8 %) were detected. Listeria was detected in 11.1 % (47 of 423) of samples, mostly in samples from lairage stable floor samples (27.3 %). Listeria was not detected in sterilisation bassins, on doorknobs, at the wall in the chilling room or on the deposition board of carcasses after depelting. The highest prevalence on the carcasses was found before depelting (12.5 %) and in the chilling room (12.5 %). Listeria isolates were L.ivanovii (57.4 %; 27 of 47), L.denitrificans (27.7 %; 13 of 47), L.monocytogenes (8.5; 4 out of 47 %) and L.innocua (2.1%; 1 of 47) were found. E.coli was detected in 60.1 % (254 of 423) of all samples, most of them were from the samples of the lairage stable floor and fleece depelting machine (100.0 % each). The highest prevalence on the carcasses was found in the chilling room (72.5 %). For Campylobacter isolates using PFGE, a relationship between some sample qualities was observed: Within particular excursions and also for different ones, the patterns of PFGE indicate the same genetic sequences of Campylobacter. Hence, transfer of Campylobacter from farm in to the slaughterhouse and the meat production process can not be excluded.
    In conclusion, thermophilic Campylobacter, Listeria and E.coli were identified on carcasses and in environmental samples especially in the lairage stable floor samples. A transfer of these pathogens from the farms to the slaughterhouse can be assumed.