Laboratory evaluation showed a similarity between prepared ready-for-use triple sugar iron agar (TSI) medium and the Oxoid form with reference to the enumeration of five test organisms related to the family Enterobacteriaceae. Storage of the prepared ready-for-use TSI medium at 20-22 degrees C should not exceed 6 months. Lowering the storage temperature to 10 degrees C raised the period of storage to two years. Combination of darkness and low temperature (10 to 20 degrees C) represents the best conditions for storage of the TSI medium in laboratories. Dark colour ampoules can extend the expiration date of the product.