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This is a base medium to which can be added selective supplements of choice for the presumptive identification and enumeration of Clostridium perfringens in food products using poured plate techniques. Sodium metabisulphite and Ferric ammonium citrate are included in the base and together provide an indicator of sulphite reaction by Clostridium perfringens, which produces black colonies on the medium. It is recommended that this medium be used with an overlay otherwise cultures may not grow as black colonies. NB: This is a base medium only and contains no selective supplements. -
Originally intended for use in surface counting and pour plating techniques this medium can be used as a general purpose medium for the cultivation of most organisms particularly those that are less fastidious in their nutritional requirements. Can also be used as a maintenance medium for stock cultures. -
Tryptone Soya Broth (Modified) with Novobiocin (20mg/L) This is a selective enrichment broth for the isolation of Escherichia coli 0157, primarily from food and food products, and is capable of detecting the organisms even when they are present in small numbers. It is also increasingly being used in clinical laboratories when screening faecal samples. Based on Tryptone Soya Broth it is made selective for Escherichia coli 0157 by the addition of bile salts and Novobiocin and is also buffered to maintain the pH during incubation. This medium is generally used in conjunction with selective agar subculture (e.g. Sorbitol MacConkey Agar with Cefixime Tellurite – (CT-SMAC)).
