Table of Contents
- 1 Why must the agar pours be cooled to 45 before use in the pour plate technique?
- 2 Do agar plates need to be refrigerated?
- 3 What would happen to plates poured with agar that is too cool could they be used?
- 4 What happens if agar is too hot?
- 5 Why do you store agar plates upside down?
- 6 How does bacteria grow on agar plates?
- 7 How to prepare nutrient agar and Mueller Hinton Media?
- 8 What happens to culture medium during steam sterilization?
Why must the agar pours be cooled to 45 before use in the pour plate technique?
The agar is cooled to approximately 45°c before preparing pour plates because to make sure that the bacteria does not die when transferred to the agar and to make sure the agar does not to solid.
What temperature should you pour agar?
Heat in one minute intervals on low power until all of the agar is melted. Between intervals, gently swirl the bottle to make sure the agar is melting evenly. While wearing heat-protective gloves, carefully remove the hot bottle and let it cool to between 75– 55°C before pouring.
Do agar plates need to be refrigerated?
All agar on plates (Petri dishes) should be stored refrigerated and should be used within one month after receiving. To prevent contamination, keep all bottles, tubes, and Petri dishes sealed until ready to use.
How long can agar plates be stored at room temperature?
If the plates were maintained at 4C, you can use them for 2 weeks (from the date of preparation). After 2 weeks you may see some dehydration, even at 4C. 3 months is too long and I would suggest making new plates. In general practice plates poured should be used within one week of preparation.
What would happen to plates poured with agar that is too cool could they be used?
Once the agar reaches this temperature, it is ready to pour. If the agar is too hot, the bacteria in the sample may be killed. If the agar is too cool, the medium may be lumpy once solidified.
Why must agar be cooled?
Why should agar be cooled to 45 degree celcus before pouring? To reduce condensation and to provide easier handling of liquid medium. produces color changes in response to differences in reactions by bacteria such as differences in fermentation of sugars; contains fermentable sugars or other differential agents.
What happens if agar is too hot?
If the agar is too hot, the bacteria in the sample may be killed. If the agar is too cool, the medium may be lumpy once solidified.
What would happen to plates poured with agar that is too hot Could they be used?
Why do you store agar plates upside down?
Petri dishes need to be incubated upside-down to lessen contamination risks from airborne particles landing on them and to prevent the accumulation of water condensation that could disturb or compromise a culture.
How long can bacteria survive on agar plate?
| Table 1. Approximate time bacterial cultures remain viable in different storage conditions. | ||
|---|---|---|
| Condition | Temp (°C) | Time (approx.) |
| Agar plates | 4 | 4 – 6 weeks |
| Stab cultures | 4 | 3 weeks – 1 year |
| Standard freezer | -20 | 1 – 3 years |
How does bacteria grow on agar plates?
Agar is a compound that is derived from algae. It contains many nutrients, and bacteria can thrive on it. It is gelatinous, and is created by mixing powdered agar with water and adding heat. After this liquid is poured into sterile Petri dishes, it solidifies into a gel and can be used as a medium for bacterial growth.
Why is preparation of agar plate culture media important?
Discussion: In this study, we focused on preparation of agar plate culture media. In the process of preparing culture medium, there are many precautions steps to be taken. This is because to ensure the accuracy composition of nutrient so the bacteria could grow perfectly inside the culture medium.
How to prepare nutrient agar and Mueller Hinton Media?
To prepare nutrient agar and Mueller Hinton agar media. 2. To weight the media using the balance. 3. To melt the agar media following instructions on the bottle. 4. To sterilize by autoclaving for 15 min at 121oC. 5. To melt the nutrient agar and Mueller Hinton agar media.
What is the difference between nutrient broth and agar plate?
Nutrient broth is in liquid form while an agar plate is in a solid form. The nutrient broth added with agar powder so that when the suspension cools down, it will coagulate as a semi-solid medium. An agar plate is a sterile petri dish that contains agar and nutrient.
What happens to culture medium during steam sterilization?
The overcooked culture medium usually appears in dark yellowish colour. In the final step the culture medium will undergo the sterilizing process. Sterilization is defined as the complete destruction of all forms of microbial life, including bacterial spores. Steam sterilization generally refers to heating in an autoclave employing saturated steam.