HiTouch™ Flexi Plate™ - VR

Principle And Interpretation

Hitouch Flexi Plates are specially developed for the microbial testing in food, pharmaceutical, cosmetic, dairy, hospitals, water works, environmental testing etc. These plates are handy and ready to use sterile media supplied in flexible disposable plates, 55 mm in diameter. It is grid scored on the base and is irradiated to ensure perfect sterility. Medium is filled aseptically and each plate is packed in pre-sterilized plastic bag. Hitouch Flexi Plateis then packed in plastic pouch wrapping. The unique flexible plate configuration ensures close contact even with uneven surfaces. where not only counts are obtained but it is also possible to select and differentiate between groups of microorganisms like coliforms (both E. coli and non E. coli ). These plates are specially developed for microbial testing, The Flexi plate medium formula is suitable for enumeration of Enterobacteriaceae and the grids enable direct reading on the plates of the number of colonies per cm2.

Violet Red Bile Agar, a modification of MacConkeys original formulation (1) is used for the enumeration of coli-aerogens bacterial group. Violet Red Bile Glucose Agar w/o Lactose, was designed for the enumeration of Enterobacteriaceae (2). It employs the selective inhibitory components crystals violet and bile salts and the indicator system glucose and neutral red. Sought bacteria will dissimilate glucose and produce purple zones around the colonies (3). ISO committee has also recommended this medium (4). Selectivity of VRBGA can be increased by incubation under anaerobic conditions and/ or at elevated temperature, i.e. equal to or above 42°C (5-7).

Peptic digest of animal tissue and yeast extract serve as sources of carbon, nitrogen, vitamins and other essential growth nutrients. Glucose is the fermentable carbohydrate, utilization of which leads to the production of acids. Neutral red indicator detects the acidity so formed. Crystal violet and bile salts mixture help to inhibit the accompanying gram-positive and unrelated flora. Sodium chloride maintains the osmotic equilibrium. Further biochemical tests are necessary for positive identification (8).