Synthesis and isolation of citric acid anhydride

✍ Scribed by A. J. Repta; T. Higuchi

• Publisher: John Wiley and Sons
• Year: 1969
• Tongue: English
• Weight: 196 KB
• Volume: 58
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.2600580434

✦ Synopsis

Keyphrases 0 Microbiological assay-seed layer dye 0 Dye incorporation-agar plate seed layer 0 Seed layer detectionaye method

Sir:

Microbiological assays by agar plate methods use a seed layer containing the test organism. This seed layer is usually poured onto a base layer, which has been solidified. Under normal conditions it is difficult to observe whether a particular plate has received the seed layer or not. To solve this problem, food dyes were evaluated for coloring the seed layer to permit visual assurance that a seed layer has been added to each plate.

FD & C Blue No. 1' was used for coloring the seed layer in penicillin assays. A 0.1 % stock solution was prepared in sterile distilled water and used 1 m1./100 ml. of seed layer. The assays were done by the standard FDA procedure2 except that all six cylinders in each of the three plates was filled with 0.05 unit/ml. of potassium 1 H . Kohnsramm & Co., Inc.