Principles and uses Irgasan Ticarcillin and Potassium Chlorate Broth (ITC) is recommended by ISO 10273 as a selective enrichment broth for the detection of the human pathogenic strain of Yersinia enterocolitica in food and water samples. Enzymatic casein digest provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group essential for bacterial growth. Magnesium chloride and malachite green, make the broth highly selective. Irgasan inhibits Gram-positive bacteria, Ticarcillin has bactericide on Gram-negative and Gram-positive bacteria and potassium chlorate has a disinfecting property.

Principles and uses
Sorbitol Peptone Broth And Bile Salts (PSB) is a medium recommended by ISO 10273 for the selective enrichment of Yersinia enterocolitica in food samples. Outbreaks of gastroenteritis associated with Yersinia enterocolitica are increasing. Contaminated food products such as pork, beef, and raw and processed milk have been identified as sources of infection.
Enzymatic digest of casein provides nitrogen, vitamins, minerals and amino acids essential for growth. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Potassium phosphates act as a buffer system. Sorbitol is the fermentable carbohydrate providing carbon and energy.

Preparation
Suspend 31 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Dispense into appropriate containers and sterilize in autoclave at 121°C for 15 minutes.

Principles and uses
Yersinia Select Agar Base (ISO 10273) is a selective and differential medium when used with supplements. The formula is based on the CIN Agar described by Schiemann, and is recommended by ISO 10273 for the isolation and detection of presumptive pathogenic Yersinia enterocolitica from a variety of clinical and food samples.
Antibiotics are added as a supplement in order to inhibit the accompanying flora. The growth of Yersinia is promoted by pyruvate as well as by the nutrients content in the base. Yersinia degrades the mannitol of the medium to an acid form; the colonies are turning to red color due to the neutral red indicator. Mannitol fermentation in the presence of neutral red produces a characteristic “bull’s-eye” colony, colorless with a red center.
Mannitol is the fermentable carbohydrate, source of carbon and energy. Enzymatic digest of gelatin and the enzymatic digest of casein and animal tissues provide nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group.
Sodium pyruvate is added as a source of energy and as a protective substance in order to overcome oxygen toxicity biologically produced by the organisms. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Magnesium sulphate is an ion required in a large variation of enzymatic reactions, including DNA replication. Neutral red is the pH indicator. Selective inhibition of Gram-negative and Gram-positive organisms is obtained through crystal violet, sodium desoxycholate and Irgasan (triclosan). Cefsulodin and novobiocin improve the inhibition of normal enteric organisms.

Preparation
Suspend 28,5 grams of the medium in 500 ml of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Sterilize in autoclave at 121 ºC for 15 minutes. Cool to 45 ºC and aseptically add one vial of Yersinia Selective Supplement Homogenize gently and dispense into Petri dishes.