Publisher Summary This chapter describes bile oxalate sorbose (BOS) broth as a two-step enrichment procedure for the recovery of Yersinia enterocolitica from foods. In this procedure pre-enrichment in yeast extract Rose Bengal broth or in tryptone soya broth is followed by selective enrichment in BOS broth. The selective agents in BOS broth are sodium oxalate, bile salts, irgasan and sodium furadantin. BOS broth was found especially useful for the isolation of serotype 0:8 strains. BOS is composed of di-sodium hydrogen orthophosphate, sodium oxalate, bile salts, sodium chloride, magnesium sulfate, sorbose, asparagines, methionine, metanil yellow, yeast extract, sodium pyruvate, sodium furadantin, and distilled or de-ionized water. The inoculation method and incubation methods for samples are also discussed. The chapter reviews that growth of yersiniae usually results in obvious turbidity. The medium should always be cultured by streaking one loopful on CIN agar.