Five different enrichment methods were studied to find an optimal method to recover Yersinia enterocolitica from swine feed samples. When the recovery of Y. enterocolitica GER-C (serotype O:3) strain was studied at 1000 CFU/g feed, phosphate-buffered saline (PBS) enrichment at 4℃ and PBS plus sorbitol and bile salts (PSB)enrichment at 4℃ and 21℃ were not effective (< 22%). In contrast, both irgasan-ticarcillin-potassium chlorate (ITC)and tryptic soy broth plus polymyxin B sulfate and novobiocin (TSBPN) enrichment methods showed a full recovery (100%) at 100-1000 CFU/g feed. At 10 CFU/g feed, both ITC and TSBPN methods still recovered the strain (> 50%).
In recovery of ATCC 9610 (serotype O:8) strain, TSBPN method was more sensitive than any other methods (P < 0.05) at 1000 CFU/g feed. Using TSBPN method, the strain was still recovered at 100 CFU/g feed, but not at 10CFU/g feed. With its sensitivity and relatively simple recipe, TSBPN was most desirable method to recover Y. enterocolitica from swine feed samples.

• Joo-Sung Kim(The University of Tennessee) Correspondence to
• F. A. Draughon(The University of Tennessee)