APT Broth

Intended Use

Recommended for the cultivation of heterofermentative lactic acid bacteria requiring high thiamine content.

Composition**

Final pH ( at 25°C): 6.7±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 46.2 grams in 1000 ml purified/distilled water. Heat if necessary to dissolve the medium completely. Dispense in tubes or flasks as desired. Sterilize by autoclaving at 15lbs pressure (121°C) for 15 minutes. AVOID EXCESSIVE HEATING.

Principle And Interpretation

APT (All purpose Tween 80) Broth is formulated as per Evans and Niven (1) for cultivation and maintenance of Lactobacillus viridescens ATCC 12706 used in the microbiological assay of thiamine. APT Broth is recommended for the cultivation of hetero fermentative lactic acidbacteria requiring high thiamine content. The composition of APT Broth is similar to APT Agar, which is formulated as recommended by APHA for the microbiological examination of cured meats, sauerkraut, except agar (4). APT Broth is used for growing Weissella viridescens ATCC12706 (formerly Lactobacillus viridescens) and also for preparing the inoculum for thiamine assay.

Although this medium was devised for Lactobacilli, it is rich due to nutrients like Tryptone, yeast extract, dextrose, polysorbate 80 and hence can support growth of commensal microflora including coliform bacteria. The metallic salts are essential for the replication of Lactobacilli or lactic Streptococci. Polysorbate 80 acts as fatty acid source.

Type of specimen

Food samples- cured meat products, tinned foods, fruit juices.

Specimen Collection and Handling

For food samples, follow appropriate techniques for sample collection and processing as per guidelines (4). After use, contaminated materials must be sterilized by autoclaving before discarding.

Warning and Precautions

Read the label before opening the container. Wear protective gloves/protective clothing/eye protection/ face protection. Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per established guidelines should be followed while handling specimens. Safety guidelines may be referred in individual safety data sheets.

Limitations :

1. Further biochemical and serological tests must be carried out for further identification.

Performance and Evaluation

Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.

Quality Control

Appearance: Cream to yellow homogeneous free flowing powder

Colour and Clarity of prepared medium: Yellow coloured clear solution in tubes

Reaction: Reaction of 4.62% w/v aqueous solution at 25°C. pH : 6.7±0.2

pH: 6.50-6.90

Cultural Response: Cultural characteristics observed after an incubation at 35-37°C for 18-24 hours.

Key : (*) Corresponding WDCM numbers. (#) Formerly known as Lactobacillus viridescens

Storage and Shelf Life

Store between 10-30°C in a tightly closed container and the prepared medium at 15-25°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated area protected from extremes of temperature and sources of ignition. Seal the container tightly after use. Product performance is best if used within stated expiry period.

Disposal

User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow established laboratory procedures in disposing of infectious materials and material that comes into contact with sample must be decontaminated and disposed of in accordance with current laboratory techniques (2,3).

Reference

1. Evans and Niven, 1951, J. Bact., 62:599.
2. Isenberg, H.D. Clinical Microbiology Procedures Handbook 2nd Edition.
3. Jorgensen, J.H., Pfaller, M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W. (2015) Manual of Clinical Microbiology, 11th Edition. Vol. 1.
4. Salfinger Y., and Tortorello M.L. Fifth (Ed.), 2015, Compendium of Methods for the Microbiological Examination of Foods, 5th Ed., American Public Health Association, Washington, D.C.