Preparing and Sterilizing Media Experiment

Intermittent sterilization

Is the "exposure to a temperature of 100°C (flowing steam) for a definite period, usually an hour, on each of several days; at each heating, the developed bacteria are destroyed; spores, which are unaffected, germinate during the intervening periods and are subsequently destroyed.

Dry heat sterilization

What is best used for sterilizing culture media, liquids and heat-sensitive items?

moist heat

The sample is placed in the steam sterilizer or boiled to introduce ________ for 10- 20 minutes, which kills the vegetative cells and mist spores will likely remain.

15-30 minutes

Sterilization takes only ________ and during this time the cell membranes of the microbes hydrolyse and the proteins coagulate and denature, killing the microbial cells.

Nutrient broth

What has already been adjusted by the manufacturer to a specific pH and also contains buffering agents to maintain it?

fastidious bacteria

As the media is nutrient- rich, it provides the optimal environment for ________ like streptococcus pneumoniae, that need specific conditions and nutrients to grow.

concept of boiling

The ________ is based upon the idea that spores are resistant to most sterilization procedures, hence the only way to get rid of them is to give them the opportunity to grow out and kill the cells before they reproduce their endospores.

Dry heat sterilization

________ involves exposing a sample for sterilization in an oven at approximately 170°C for 2 to 3 hours under atmospheric pressure.

Complex media

________ contain many animal or plant tissue- derived compounds such as yeast extract, peptones from plants or albumin serums whose quantity and concentrations are unknown.

MEDIA MIX

Table 1: TABLE SHOWING THE AMOUNT OF WATER AND ________ REQUIRED TO MAKE THE CORRECT AMOUNT OF MEDIUM.

Amount of agar used

(Agar % ÷ 100) × Water

Percentage of media that is agar

Agar ÷ Water

Amount of water present in the media

Media mix ÷ Bottle label

Amount of media mix present in the media

Bottle label × water

Correct media proportions on the bottle label

Media mix ÷ water

The same as the water volume

What is the final volume?

Defined media

What is media has all the chemicals known and none of the components is microbial or animal-derived?