TT (Tetrathionate) Broth Base, Hajna is used for enriching Salmonella from food and dairy products prior to isolation procedures.
TT Broth Base, Hajna is used as a selective enrichment for the cultivation of Salmonella spp. Salmonella organisms can be injured in food-processing procedures. These procedures include exposure to low temperatures, sub-marginal heat, drying, radiation, preservatives and sanitizers.1 Although injured cells may not form colonies on selective media, they can cause disease if ingested.2 Salmonella spp., in particular, cause many types of infections from mild self-limiting gastroenteritis to life-threatening typhoid fever.3 The most common form of Salmonella disease is self-limiting gastroenteritis with fever lasting less than 2 days and diarrhea lasting less than 7 days.3
TT Broth Base, Hajna conforms to the formulation of Hajna and Damon.4 The medium is a modification of the enrichment described by Kauffmann5 and Knox.6 Hajna and Damon4 developed a new broth containing yeast extract, peptone, carbon sources and the selective agents, sodium desoxycholate and brilliant green (replacing bile salts).
TT Broth Base, Hajna is used in testing Salmonella in egg processing plants.7 It is included in procedures for the isolation and identification of Salmonella from meat and poultry as well as egg products.8
Peptone provides nitrogen and amino acids. Yeast extract supplies growth factors and vitamins. Dextrose and mannitol are fermentable carbohydrates. Selectivity is accomplished by the combination of sodium thiosulfate and tetrathionate, suppressing coliform organisms.6 Tetrathionate is formed in the medium by the addition of a solution containing iodine and
potassium iodide. Organisms containing the enzyme tetrathionate reductase will proliferate in this medium.
Sodium desoxycholate and brilliant green are selective agents that suppress coliform bacteria and inhibit gram-positive organisms. Sodium chloride maintains the osmotic balance of
the medium. Calcium carbonate is a neutralizer that absorbs toxic metabolites.
TT Broth Base, Hajna
Approximate Formula* Per Liter
Yeast Extract................................................................. 2.0 g
Tryptose..................................................................... 18.0 g
Dextrose...................................................................... 0.5 g
D-Mannitol.................................................................... 2.5 g
Sodium Desoxycholate................................................... 0.5 g
Sodium Chloride............................................................ 5.0 g
Sodium Thiosulfate...................................................... 38.0 g
Calcium Carbonate....................................................... 25.0 g
Brilliant Green.............................................................. 0.01 g
*Adjusted and/or supplemented as required to meet performance criteria.
Identity Specifications
TT Broth Base, Hajna
Dehydrated Appearance: Beige to very light green, free-flowing, homogeneous.
Solution: 9.15% solution, partially insoluble in purified water upon boiling. Solution is light green, slightly opalescent with a heavy white precipitate.
Prepared Appearance: Light green, slightly opalescent with a heavy white precipitate.
Reaction of 9.15%
Solution at 25°C: pH 7.6 ± 0.2 (after addition of the iodine solution)
Cultural Response
TT Broth Base, Hajna
Prepare the medium per label directions. Inoculate and incubate at 35 ± 2°C for 18-24 hours. After incubation, plate the inoculated broth onto MacConkey Agar and incubate at 35 ± 2°C for 18-24 hours.
ORGANISM | ATCC™ |
INOCULUM |
RECOVERY | COLONY COLOR ON MACCONKEY AGAR |
Escherichia coli | 25922 | 102-103 | None to poor | Pink with bile precipitate |
Salmonella enterica subsp. enterica serotype Typhimurium |
14028 | 102-103 | Good | Colorless |
1. Suspend 91.5 g of the powder in 1 L of purified water. Mix thoroughly.
2. Heat to boiling. DO NOT AUTOCLAVE. Cool to below 50°C.
3. Add 40 mL iodine solution (5 g iodine crystals and 8 g potassium iodide dissolved in 40 mL of purified water) and mix well.
4. Dispense into sterile tubes while keeping suspension well mixed. Do not heat the medium after adding iodine.
5. Test samples of the finished product for performance using stable, typical control cultures.
After preparation, add 1-3 g of fecal specimen to each tube (heavy inoculum). Incubate tubes for 12-24 hours at 35 ± 2°C in an aerobic atmosphere.
Growth is indicated by turbidity in the medium. Subculture to selective and differential enteric plating media for further investigations.
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