What is a disadvantage of the streak plate technique?
Streak plating is a microbiology laboratory method that has two major disadvantages. Firstly, users will not be able to grow obligate anaerobes using this method. Secondly, only organisms that were viable in the original sample are able to be grown.
How do you know if a streak plate method was performed correctly?
If you streaked correctly, you will see isolated colonies in the third sector. The heaviest growth will be in the first sector. There will be less growth and some isolated colonies in the second sector. The third area should have the least growth with isolated colonies.
What factors would account for an absence of growth on a streak plate?
Streak Plate – should appear near or in a vaccinity of streak lines and sections. E9 – What factor(s) could accunt for an absence of growth on a pour plate? The lack of oxygen, poor/ bad bacteria smear, or difference in temperature that prevents optimal growth, within media.
What are the advantages and disadvantages of spread plate method?
Advantages and Disadvantages of Spread Plate Technique
- The optimum method for aerobes while microaerophilic tends to grow slower.
- The dilutions should be Accurate.
- The volume of inoculum greater than 0.1 mL on the nutrient agar not soak well and may result in colonies to coalesce as they form.
What are the advantages and disadvantages of pour plate method?
Advantages of Pour Plate Technique
- Easy to undertake.
- Will detect lower concentrations than surface spread method because of the larger sample volume.
- It requires no pre-drying of the agar surface.
- The most common method for determining the total viable count is the pour-plate method.
How can you tell if a streak plate is 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 is the disadvantage of pour plate?
Disadvantages of Pour plate method Preparation for the pour plate method is time-consuming compared with the streak plate/and or spread plate technique. Loss of viability of heat-sensitive organisms coming into contact with hot agar. Embedded colonies are much smaller than those which happen to be on the surface.
What are some reasons for not getting isolated colonies from a streak plate?
The culture plate has colonies that do not look like most of the colonies, or there are colonies where nothing was streaked. Reason: The plate has become contaminated with bacteria or fungi from the environment. is pure (free of any contaminants).
How would your streak plate technique be improved?
How could your streak plate method be improved? Because the purpose of a streak plate is to obtain isolated cultures from an inoculum, consider using a fourth quadrant to further increase the probability of isolated cultures.
When streaking a plate the loop should be flamed?
1. Flame the inoculating loop until it is red hot and then allow it to cool. 2. Remove a small amount of bacterial growth (either a loopful from a broth culture or a single colony from a plate or slant) with the sterile inoculating loop.
What is a successful 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 the principle of streak plate method?
Principle of Streak Plate. The streak plate method is a rapid qualitative isolation method. The techniques commonly used for isolation of discrete colonies initially require that the number of organisms in the inoculums be reduced. It is essentially a dilution technique that involves spreading a loopful of culture over the surface of an agar plate.
What are the disadvantages of streak plate?
If you are not skilled enough, then you would end up tearing through the agar, especially if you apply too much pressure on the agar. A wrong streaking method can ruin your plate. The streak plate method can be time-consuming, especially if you are going to prepare a large sample size.
What is the difference between streak plate method and microbiological culture?
If the agar surface grows microorganisms which are all genetically same, the culture is then considered as a microbiological culture. Streak Plate Method is done by diluting a comparatively large concentration of bacteria to a smaller concentration.
How to handle specimen streaked on plate?
The specimen streaked on a plate could come in a variety of forms, such as solid samples, liquid samples, and cotton or foam swabs. Material containing possibly infectious agents should be handled appropriately in the lab using bio safety procedure.