Overview of the two culture methods used in this study, both somewhat modified from the original. (i) A method based on the NMKL method no. 117 (1996), that includes cold enrichment, selective enrichment and subculture on a selective agar plate and (ii) a TaqMan-PCR based method (Thisted Lambertz, 2008) that includes enrichment overnight in 25°C, PCR analysis and subculture on a selective agar plate. The step indicated by dotted lines was performed if no characteristic pathogenic Y. enterocolitica colonies were visible on CIN agar day 1. Number 1–6 refer to the different subculturing (CIN) sampling steps as indicated in Table 1. CIN, Cefsulodin Irgasan Novobiocin; PW, Peptone water; PSB, Phosphate-buffered saline containing 2% sorbitol and 0.15% bile salts; TSBY, Tryptone-soya broth supplemented with yeast; KOH, Potassium hydroxide solution; MRB, Modified-Rappaport-broth.