NEUTRALIZING BROTH CAT Nº: 2003 For the detection of microorganisms on surfaces of sanitary interest FORMULA IN g/l Dextrose 10.00 Yeast Extract 2.50 Lecithin 7.00 Sodium Bisulfite 2.50 Sodium Thiosulfate 6.00 Sodium Thioglycollate 1.00 Casein Peptone 5.00 Bromocresol Purple 0.02 Polysorbate 80 5.00 Final pH 7.6 ± 0.2 at 25ºC PREPARATION Suspend 39 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. Distribute into appropriate containers and sterilize in autoclave at 121ºC for 15 minutes. The prepared medium should be stored at 2-8°C. The color is violet. The dehydrated medium should be homogeneous, free-flowing and green-blue in color. If there are any physical changes, discard the medium. USES NEUTRALIZING BROTH is used to cultivate a broad range of microorganisms while neutralizing disinfectants and antimicrobials which have inherent bacteriostatic properties. Peptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Dextrose is the fermentable carbohydrate providing carbon and energy. Five neutralizers inactivate a number of disinfectant and antiseptic chemicals. Sodium bisulfite neutralizes aldehydes. Sodium thioglycollate neutralizes mercurials. Sodium thiosulfate neutralizes iodine and chlorine. Lecithin neutralizes quaternary ammonium compounds. Polysorbate 80, a non- ionic surface active agent, neutralizes substituted phenolics. Bromocresol purple is used as an indicator for dextrose utilization. The organisms that ferment dextrose will turn the medium from a purple to yellow color. Inoculate and incubate at 35±2°C and observed after 18-24 hours. MICROBIOLOGICAL TEST The following results were obtained in the performance of the medium from type cultures after incubation at a temperature of 35±2°C and observed after 18-24 hours. Microorganisms Growth Escherichia coli ATCC 25922 Good Bacillus subtilis ATCC 6633 Good Pseudomonas aeruginosa ATCC 27857 Good Staphylococcus aureus ATCC 25923 Good Salmonella typhimurium ATCC 14028 Good 1 LABORATORIOS CONDA, S.A. www.condalab.com BIBLIOGRAPHY Downes and Iro(ed), 2001. Compendium of method for the microbilogical examination of foods, 4th ed. American Public Health Association, Washitong, D.C. Association for the Advancement of Medical Instrumentation. 1984. Process control guidelines for gamma radiation sterilization of medical devices. AAMI, Arlington,VA STORAGE 25ºC Once opened keep powdered medium closed to avoid hydration. 2ºC 2 LABORATORIOS CONDA, S.A. www.condalab.com