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Biochemical Reagents

Sector: Industrial

`CALGON’ RINGERS TABLETS

Code: BR0049

Formula

gm/litre

Sodium chloride

2.25

Potassium chloride

0.105

Calcium chloride 6H2O

0.12

Sodium bicarbonate

0.05

Sodium hexametaphosphate (’Calgon’)

10.0

One tablet makes 10ml of quarter-strength Ringer Solution containing 1% of `Calgon’. (Sodium hexametaphosphate.)

Directions
To prepare a solution containing 1% sodium hexametaphosphate in quarter-strength Ringers Solution, dissolve 1 tablet in 10ml of distilled water. Sterilise by autoclaving at 121° C for 15 minutes.

Description
Higgins1 showed that bacteriological swabs prepared from calcium alginate wool will dissolve completely in `Calgon’ Ringers Solution, thus releasing all the organisms taken up on the swab and giving a more accurate quantitative recovery. She concluded that the use of this material in place of cotton-wool for the preparation of swabs, seemed justified in quantitative work since the recovery of organisms was much greater.
This principle was successfully applied to the bacteriological examination of tableware2 and also of crockery and kitchen utensils3.
Trimarchi4 found that calcium alginate swabs were superior to raw cotton swabs for the bacteriological examination of eating utensils.

Also see:
BR0048     Thiosulphate Ringers Tablets
BR0052     Rngers Solution Tablets

Technique
Prepare swabs, using approximately 25-50 milligrams of alginate wool to each wooden applicator. Sterilise, in plugged tubes, by autoclaving at 121° C for 15 minutes. After swabbing, aseptically break off the swab end and drop into a screw- top bottle containing 10ml of sterile `Calgon’ Ringer Solution. Close the bottle and shake vigorously for 10-30 minutes to disperse the alginate wool completely. The suspension may then be examined quantitatively or qualitatively in the usual manner.

References
1 Higgins M. (1950) Mon. Bull. Min. Hlth Pub. Hlth Lab Serv. 9. 50-51.
2 Higgins M. and Hobbs B. C. (1950) Ibid. 38-49.
3 Higgins M. (1950) Ibid. 52-53.
4 Trimarchi G. (1959) Igiene Moderna 52. 95-111.

 
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