Jump to main content
Jump to site search

All chapters
Previous chapter Next chapter

Chapter 15

Culture Media for the Isolation of Yersinia enterocolitica from Foods

Yersinia enterocolitica and Yersinia pseudotuberculosis are recognised as food-borne pathogens, and outbreaks and sporadic cases of yersiniosis have been reported in many countries, especially in the northern hemisphere. Many selective enrichment and plating media for the isolation of Yersinia enterocolitica from foods have been described. Use of many of these results in the isolation of non-pathogenic as well as pathogenic Yersinia strains. At present, no single isolation procedure is optimal for the recovery of all pathogenic strains of Y. enterocolitica. Cold enrichment in phosphate-buffered saline plus 1% sorbitol and 0.15% bile salts (PBSSB) and two-step enrichment with tryptone soy broth (TSB) and bile oxalate sorbose (BOS) broth are useful methods for the recovery of a wide spectrum of Y. enterocolitica serotypes. Enrichment in Irgasan ticarcillin chlorate (ITC) broth is the most efficient method for recovery of strains of biotype 4/serotype 0:3, the most prevalent clinical bio/serotype of Y. enterocolitica in Europe. Post-enrichment alkali treatment often results in higher isolation rates. Cefsulodin Irgasan novobiocin (CIN) agar and Salmonella-Shigella deoxycholate calcium chloride (SSDC) agar are the most frequently used plating media. Selection of the proper isolation procedure will depend on the bio/serotypes of Yersinia spp. sought and on the type of food to be examined. Use of more than one medium for both enrichment and plating will result in higher recovery rates of Yersinia spp. from foods. Biotyping and serotyping is essential for differentiation between pathogenic and nonpathogenic Yersinia strains. The International Organization for Standardization method for the detection of presumptive pathogenic Y. enterocolitica includes parallel use of the following two isolation procedures: (1) enrichment in peptone, sorbitol and bile salts (PSB) broth for 2–3 days at 22–25°C with agitation or 5 days without agitation, then plating on CIN agar directly, alkaline treatment and incubation for 24h at 30°C; (2) enrichment in ITC for 2 days at 25°C; plating on SSDC agar and incubation for 2 days at 30°C.

Publication details

Print publication date
06 Dec 2011
Copyright year
Print ISBN