What is solid culture media?

What is solid culture media?

Solid media is used for the isolation of bacteria as pure culture. ‘Agar’ is most commonly used to prepare solid media. Agar is an ideal solidifying agent as it is : (a) Bacteriologically inert, i.e. no influence on bacterial growth, (b) It remains solid at 37°C, and (c) It is transparent.

What is an example of solid media?

Agar is used as a solidifying agent in most culture media. By varying the concentration of agar, it is possible to make the medium solid or semisolid. Other examples of solid media include blood agar, chocolate agar, MacConkey agar, etc.

What is the difference between solid and liquid media?

The key difference between solid and liquid media is that solid media contain agar while liquid media do not contain agar. But, liquid media are used for various purposes such as propagation of a large number of organisms, fermentation studies, and various other tests.

How are media solidified?

Liquid media are often mixed with agar and poured via a sterile media dispenser into Petri dishes to solidify. These agar plates provide a solid medium on which microbes may be cultured. Bacteria grown in liquid cultures often form colloidal suspensions.

What is solid media used for?

Solid media is used for the isolation of bacteria as pure culture. ‘Agar’ is most commonly used to prepare solid media. Agar is polysaccharide extract obtained from seaweed.

How do you make bacteria stab?


  1. Fill airtight, autoclavable vials with rubber or teflon caps 2/3 full of stab agar.
  2. Inoculate with a single colony repeatedly poking the inoculating loop into the agar.
  3. Incubate at 37°C for 8-12 hrs until cloudy tracks of bacteria become visible.
  4. Seal tightly and store in the dark at room temperature (15-22°C)

What is a loop made of?

The tool consists of a thin handle with a loop about 5 mm wide or smaller at the end. It was originally made of twisted metal wire (such as platinum, tungsten or nichrome), but disposable molded plastic versions are now common.

How are inoculating loops and needles heated?

Heat the inoculating loop in the Bunsen burner until it is red hot. Heat several inches of the loop, since that much of it will contact the inside of the tubes. Allow the loop to cool for a few seconds while you hold it in your hand. Do not put it down or allow the loop to touch any surface after it is sterile.

How could you tell if your plate was contaminated?

Checking for Contamination Look for signs of fungal contamination. Fungal contamination will appear as fuzzy, filamentous, or hair-like growths, and should be visible to the unaided eye. Fungal contamination often occurs right along the edge of an agar plate.

What does clamshell the plate mean?

the first streak inoculates large numbers of bacteria into a small section of the plate. when opening as agar plate always (clamshell) keep it partially closed on one side to protect the agar from bacteria drifting down from overhead. you do this every time between flaming.

What is the goal of a streak plate?

A streak plate involves the progressive dilution of an inoculum of bacteria or yeast over the surface of solidified agar medium in a Petri dish. The result is that some of the colonies on the plate grow well separated from each other. The aim of the procedure is to obtain single isolated pure colonies.

What is a pour plate?

: a plate prepared by mixing the inoculum with the cooled but still fluid medium before pouring the latter into the petri dish.