PSB Broth, Modified is recommended for primary enrichment and enumeration of Yersinia enterocolitica from food in accordance with ISO/DIS 10273:2017. This medium is a modification of PSB Broth and is recommended by ISO Committee for primary enrichment and enumeration of Yersinia enterocolitica from foods. Supplementation of phosphate buffer with sorbitol and bile salts appears to be better for cold enrichment. Bile salts are added to make the medium selective for Yersinia species by inhibiting accompanying gram-positive bacteria.