Technical Data
Lactobacilli MRS Broth, Defined, w/o Thymine, Folic Acid (Powder)
Microbiological Grade
Storage 4°C    Shipping RT
Formulation g/Liter
Inorganic Salts
Ammonium Citrate, Dibasic2.0
Ascorbic Acid 0.5
Cobalt Sulfate0.5
Glucose 10.0
Calcium Lactate1.0
Magnesium Sulfate•7H2O0.5
Manganese Sulfate•H2O0.02
Tween (Polysorbate) 801.0
Potassium Acetate10.0
Potassium Phosphate Dibasic3.1
Potassium Phosphate Monobasic1.5
Sodium Chloride0.02
Amino Acids
DL-Aminobutyric Acid0.1
L-Aspartic Acid0.3
L-Glutamic Acid0.3
L-Histidine HCl0.2
L-Lysine HCl0.2
p-Aminobenzoic Acid (PABA)0.0002
Nicotinic Acid0.01
Calcium Pantothenate0.01
Pyridoxal HCl0.01
Folic AcidAbsent
This is a special chemically-defined medium without Thymine, Thymidine or Folic Acid.

Suitable for use in the cultivation of Lactobacilli from dairy products and other materials. Lactobacilli MRS Broth is based on the formulations of deMan, Rogosa and Sharpe (MRS). This medium supports luxuriant growth of Lactobacilli from oral, fecal, dairy and other sources.

Animal tissue digest, beef extract and yeast extract, normally the carbon, nitrogen and vitamin sources used to satisfy general growth requirements in Lactobacilli MRS Broth, are absent and replaced with supplements and vitamins.

Dextrose is the fermentable carbohydrate. Potassium acetate and ammonium citrate act as selective agents as well as energy sources. Potassium phosphate is the buffering agent. Magnesium sulfate and manganese sulfate provide cations used in metabolism. Polysorbate (Tween) 80 is a surfacant, facilitating uptake of nutrients by Lactobacilli.

Directions per Liter: Dissolve 33.69g in 800-900ml of ddH2O stirring gently until completely solubilized. If required, add sodium bicarbonate. Adjust pH of the medium to the desired level. Add additional water to bring the solution to1L Filter-sterilize using a 0.22 micron membrane filter. Aliquot into sterile containers. Do not autoclave. Contains heat-labile compounds that can be damaged with autoclaving.

Storage and Stability: Store powdered media at 4ºC. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4°C and used within a short period of time.Test procedure: Samples can be inoculated directly into Lactobacillus MRS Broth. Incubate broth tubes at 35°C for 3 days, or at 30°C for 5 days in an aerobic atmosphere. Subculture growth in broth tubes to appropriate solid media.Results: Growth of Lactobacillus spp. appear turbid. Growth can be subcultured onto appropriate media for use in additional procedures. Refer to appropriate references for recommendation on the identification of Lactobacillus spp.Limitations: Due to varying nutritional requirements, some strains may be encountered that grow poorly or fail to grow on this medium. Organisms other than lactobacilli may grow in this medium. Isolates must be confirmed as lactobacilli by appropriate biochemical testing.

Appearance: White to light tan, homogeneous,, free flowing powder.

Solubility: Yellow to golden yellow, clear after sterile filtering

pH: As Reported

Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.

1. J. Applied Micro., 88:695-703 (2000) 2. deMan, J. C., M. Rogosa and M. E. Sharpe, 1960. A medium for the cultivation of lactobacilli. J. Bacteriol. 23:130. 3. MacFaddin, J. F. 1985. Media for the isolation, cultivation, identification and maintenance of medical bacteria, vol. 1 Williams & Wilkins, Baltimore, MD. 4. Vanderzant, C. and D. F. Splittstoesser (eds.). Compendium of methods for the microbiological examination of foods, 3rd ed. American Public Health Association, Washington, D. C. 5. Murray, P. R., E. J. Baron, M. A. Pfaller, F. C. Tenover and R. H. Yolken (eds.). 1995. Manual of clinical microbiology, 6th ed. American Society for Microbiology, Washington, D. C.