Description
Use and description:
This medium recommended by USP and APHA is used to count aerobic bacteria in water, milk and other food products.
Composition per litre:
Yeast extract……………………………. 2.5 g
Tryptone……………………………………5.0 g
Glucose……………………………………..1.0 g
Agar…………………………………………15.0 g
Final pH of the ready to use medium: 7.0 ± 0.2
Medium preparation:
Add 23.5 grams of dehydrated culture medium to 1 litre of distilled water. Bring to the boil with frequent stirring to dissolve. Dispense into tubes and sterilise by autoclaving for 15 min at 121°C. Cool to 44-46°C for not more than 3 hours prior to use. Incubate at 32-35°C for 48 hours.
Quality specifications:
Dehydrated medium: homogeneous, cream coloured fine powder.
Ready to use medium: light amber agar, very slightly opalescent.
Microbiological response:
| Organism | Result |
| Staphylococcus aureus ATCC 25923 | Good growth |
Storage:
Dehydrated medium should be stored between 10 to 25°C. Once opened, place the container in a dark, dry place. The dehydrated medium should not be used if there is any lump or if the colour has changed from the original.
500g wrapped pots