Hardy Diagnostics HUGO

LACTOSE BROTH MEDIA

Cat. no. K137 Lactose Broth, Double Strength (DS), 20x125mm Tube with Durham Tube, 10ml 20 tubes/box
Cat. no. K223 Lactose Broth, 16x125mm Tube with Durham Tube, 10ml 20 tubes/box
Cat. no. U92 Lactose Broth, 180ml Wide Mouth Jar, 99ml 12 jars/box
Cat. no. U136 Lactose Broth, 180ml Wide Mouth Jar, 90ml 12 jars/box
Cat. no. U145 Lactose Broth, 500ml Polycarbonate Bottle, 225ml 10 bottles/box
Cat. no. U146 Lactose Broth, 12oz. Wide Mouth Jar, 225ml 12 jars/box
Cat. no. U105 Lactose Broth with Lecithin and Tween® 80, 8oz. Wide Mouth Jar, 90ml 12 jars/box

INTENDED USE

Hardy Diagnostics Lactose Broth and Lactose Broth with Lecithin and Tween® media are used to detect coliforms in food, dairy products, and water. These formulations can also be used to pre-enrich samples for the recovery of Salmonellaspecies.

This product is not intended to be used for the diagnosis of human disease.

SUMMARY

Lactose Broth is frequently used as a pre-enrichment broth during testing of foods and dairy products for Salmonella. In processed foods, Salmonella species can be present in low concentrations and the cells may be found in a debilitated condition. Lactose Broth provides an environment favorable for the recovery of Salmonella. The media allows damaged cells to recover, dilutes toxic substances that may be present, and favors growth of Salmonella over other species.(2) Lactose Broth is included in many procedures for testing foods, dairy products, and other materials.(1-4)

A pre-enrichment medium provides a higher ratio of Salmonella to non-Salmonella bacteria after incubation. Most non-Salmonella bacteria ferment lactose, while Salmonella does not. When lactose-fermenting bacteria metabolize lactose in the medium, the pH decreases, creating a bacteriostatic effect on competing microorganisms.

Lactose Broth is also used to detect coliforms in food, dairy products, and water.(1-4) The concentration of ingredients in Lactose Broth, when used to detect coliforms in samples, must remain the same after addition of the sample being tested. Lactose Broth with lecithin and Tween® formulations aid in neutralizing disinfectants or preservatives that may inhibit bacterial cells. Neutralization of these residues reduces their inhibitory effects and aids in the recovery of sub-lethally injured cells.

FORMULA

Ingredients per liter of deionized water:*

Pancreatic Digest of Gelatin 5.0gm
Lactose 5.0gm
Beef Extract 3.0gm

In addition, Cat. no. U105 contains:

Lecithin 0.7gm
Tween® 80 5.0ml

Final pH 6.9 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.

STORAGE AND SHELF LIFE

Storage: Upon receipt store media at 2-8ºC. (store Cat. no. U146 at 2-30ºC.) away from direct light. Media should not be used if there are any signs of deterioration (discoloration), contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat and freezing.

PRECAUTIONS

PROCEDURE

Allow media to warm to room temperature before inoculation.

1. Transfer a 25.0gm, or 25ml, sample of test material into a container. Add 225ml of sterile Lactose Broth. Mix as necessary to make a homogeneous suspension. Incubate at 35ºC. for 24 hours.

2. Transfer 1ml of suspension to appropriate enrichment broths, such as Tetrathionate Broth (Cat. no. K65) and Selenite Cystine Broth (Cat. no. K69). Incubate at 35ºC. for 24 hours.

3. Transfer a loopful of suspension to appropriate selective agar media, such as Hektoen Enteric Agar (Cat. no. G63), XLD Agar (Cat. no. G65) and Bismuth Sulfite Agar. Incubate at 35ºC. for 24 hours.

INTERPRETATION OF RESULTS

Pre-enrichment, selective enrichment and selective plating increase the likelihood of isolating Salmonella from foods and other materials.(1-5)

LIMITATIONS

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, etc., are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Escherichia coli
ATCC ® 25922
A 18-48hr 35°C Aerobic Growth; acid and gas production**
Salmonella enterica
ATCC ® 14028
A 18-48hr 35°C Aerobic Growth; no acid or gas production**

**When Durham tube present.

User Quality Control

PHYSICAL APPEARANCE

Lactose Broth media should appear clear, and light to medium amber in color.

REFERENCES

1. American Public Health Association. Standard Methods for the Examination of Dairy Products, APHA, Washington, D.C.

2. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the Microbiological Examination of Foods, APHA, Washington, D.C.

3. U.S. Food and Drug Administration. Bacteriological Analytical Manual. AOAC, Arlington, VA.
http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm2006949.htm.

4. American Public Health Association. Standard Methods for the Examination of Water and Wastewater, APHA, Washington, D.C.

5. The Official Compendia of Standards. USP-NF. United States Pharmacopeial Convention, Rockville, MD.


ATCC is a registered trademark of the American Type Culture Collection.
Tween is a registered trademark of ICI Americas, Inc.

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