MKTTn Broth EMD Chemicals Inc.

MKTTn Broth

Cat. No. 1.05878.0500
(500 g)
Product available February 2005

For the selective enrichment of salmonellae from food and animal feed according to ISO 6579.

Mode of Action	Preparation
Typical Composition (g/liter)	Quality Control
Additives/Reagents	Experimental Procedure and Evaluation
Literature

Mode of Action
Tetrathionate is produced from thiosulfate by adding iodine to the culture medium. Tetrathionate suppresses the growth of coliform and other enteric bacteria. Salmonella, Proteus, and some other species of bacteria can reduce tetrathionate and are not inhibited. Calcium carbonate buffers the sulfuric acid, which is liberated when tetrathionate is reduced. Bile promotes the growth of Salmonella, but largely inhibits the accompanying bacteria. Brilliant green and novobiocin primarily inhibit the growth of Gram-positive bacteria.

Typical Composition (g/liter)
Meat extract 4.3; peptone from casein 8.6; sodium chloride 2.6; calcium carbonate 38.7; sodium thiosulfate water free 30.5 (equivalent to 47.8g sodium thiosulfate pentahydrate); ox bile 4.78; brilliant green 0.0096; novobiocin 0.040.
Also to be added:
Potassium iodide 5.0; iodine 4.0; dissolved in 20 ml water

Preparation
Suspend 89.5 g in 1 liter of purified water, heat briefly (5 min.) by boiling and cool rapidly. A sediment of calcium carbonate is formed on the bottom of the tubes in the turbid broth. Adjust the pH, if necessary, to 8.2 ± 0.2 at 25°C.

DO NOT AUTOCLAVE!

The basal medium without iodine/potassium iodide solution has a shelf life of up to 4 weeks at 2-8°C.

Preparation of the iodine/potassium iodide solution: Completely dissolve 5g potassium iodide in 2 ml of water, then add 4 g iodine and dilute to 20 ml distilled water.

Prior to use add 20 ml iodine/potassium iodide solution to 1 liter of base medium. Aseptically transfer the medium into sterile flasks of suitable capacity to obtain the portions necessary for the test. Avoid further heating.

The ready-to-use broth must be prepared and used the same day.

The medium is turbid and green with a white sediment (calcium carbonate).

Experimental Procedure and Evaluation
Directly suspend approximately 1 ml of culture into 10 ml Muller-Kauffmann Tetrathionate-Novobiocin Broth according to ISO 6579.

Incubation: 21-27 hours at 36-38°C.

Streak material from the resulting cultures onto selective media according to ISO 6579.

Quality control

Test strains	Inoculum	Growth after 24 hours
Salmonella typhimurium ATCC 14028	approx. 1%	> 95%
Escherichia coli ATCC 25922	approx. 99%	< 5%
Proteus mirabilis ATCC 29906	approx. 99%	< 5%

Additives

EMD Cat. No.	Product	Pack Size
1.04761.0100	Iodine resublimed	100 g
1.05043.0250	Potassium iodide	250 g

Literature

B�NFFER, J.R.: Comparison of the isolation of Salmonellae from human faeces by enrichment at 37°C and at 43°C. - Zbl. Bakt. I. Orig., 217; 35-40 (1971).
ISO 6579 2002 International Standardization Organization. Microbiology of Food and animal feeding stuffs - Horizontal method for the detection of Salmonella spp.
EDEL, W., a. KAMPELMACHER, E.H.: Salmonella isolation in nine European laboratories using a standardized technique. - Bull. Wld. Hlth. Org., 41; 297-306 (1969).
KAUFFMANN, F.: Ein kombiniertes Anreicherungsverfahren f�r Typhus- und Paratyphusbazillen. - Zbl. Bakt. I. Orig., 119; 148-152 (1930).
KAUFFMANN, F.: Weitere Erfahrungen mit dem kombinierten Anreicherungsverfahren f�r Salmonellenbacillen. - Z. Hyg. Infekt.-Krkh., 117; 26-32 (1935).
MULLER, L.: Un nouveau milieu d'enrichissement pour la recherche du bacille typhique et des paratyphiques. - Comp. rend. Soc. biol., 89; 434-437 (1923).