2. Methods


2.1 Equipment List

Item
Quantity
Medium-sized eggs
12
Egg tray
1
Tap water
-
Beaker
1
Oticide cleaner
2-3 drops
Fridge
1
Agar Plate
8
Cotton swab
8
Para flims
8 pieces
Incubation Chamber
1
Gloves
3 (per session)  

2.2 Diagrams of experimental setup  

Figure 1: Diagrams of the procedures

Step 1


Wash, dry and store the egg according to prescribed wash time, dry method and storage time.


                                       Fig 1.





Step 2


Using a cotton swab, swab the outer surface of each egg shell by rolling the cotton swab on the shell in all direction for 5 seconds. (to ensure all sides of the cotton swab have bacteria



Fig 2.


Step 3


Swipe the surface of the agar with the cotton swab. Be careful to not tear the agar.


             
                Fig 3.


Step 4


Seal the agar plate with the parafilm tightly. Remember to label every plate.

              Fig 4.


Step 5




Fig 5.
Incubate the agar plates for 1-2 days at in the incubation chamber. Remember to place the agar plates inverted in to incubation chamber.

Step 6: Record data into Table 2.3.

The above diagram is a visual representation of the procedures of our experiments.


2.3 Procedures

  1. Wash, dry and store the egg according to the below table.

Table 1: Shows how we stored our eggs according to.              
Time Washed
Drying Method
Storage Location
Sample Name  
Not washed
-
Fridge (24 hours)
1A
Not washed
-
Fridge (24 hours)
1B
10 seconds
Naturally
Fridge (24 hours)
2A
10 seconds
Naturally
Fridge (24 hours)
2B
20 seconds
Naturally
Fridge (24 hours)
3A
20 seconds
Naturally
Fridge (24 hours)
3B
50 seconds
Naturally
Fridge (24 hours)
4A
50 seconds
Naturally
Fridge (24 hours)
4B



Figure 7 above shows the washed eggs being stored in the lab fridge at 7 degrees Celsius.

2. Using a cotton swab, swab the outer surface of each egg shell by rolling the cotton swab on the shell in all direction for 5 seconds.  (to ensure all sides of the cotton swab have bacteria)    



Figure 8 above shows us swabbing the egg shell with the disposable cotton swab.

3. Swipe the surface of the agar with the cotton swab. Be careful to not tear the agar.







                         Figure 9 above shows us swabbing the agar after swabbing the egg shell.

4. Seal the agar plate with the parafilm tightly. Remember to label every plate.
Figure 10 above shows a agar plate sealed with parafilm and labelled with masking tape.
 
5. Incubate the agar plates for 1-2 days at in the incubation chamber. Remember to place the agar plates inverted in to incubation chamber.
Figure 11 above shows the inverted agar plates in the incubator.

6. After 3 days, take out the bacteria and observe them carefully. (Record the observations in Table)
  1. Count the number of bacteria colonies.
  2. Look at the shape of the bacteria colonies.
  3. Look at the characteristics of the bacteria colonies.
  4. Draw an inference or conclusion from the bacteria colonies.  


2.4 Risk Assessment and Management  

What is the Risk
Assessment
How to Resolve?
Spilled water (When washing the egg) may be a slip hazard and can cause us to be injured (to a certain extent).
Medium
Be careful to not splash the water while washing eggs and be sure to wipe any spills.
We might accidentally come into contact with the oticide cleaner which may cause skin irritation and allergies.
Low
Handle the oticide cleaner with care. Always wear gloves when dealing the the oticide cleaner and at all time in the experiment.
When handling the drill for drilling holes into the egg tray, we might get injured.
Medium
Handle it with care and ask for help if needed.
We might accidentally come into contact with the bacteria, which causes us to get sick.
Medium
Wear gloves at all times of the experiment and make sure that the egg shell does not come into contact with any bodily fluids. Rinse with water thoroughly if contacted.


2.5 Data Analysis

  1. Rank the agar colonies to determine the bacteria present. We have adopted a scale of 1 to 10. This is done based on observation. We will also describe the shape and characteristics of bacteria growth. After that, we will take a picture and keep records.

  1. After that, we will also use Adobe Photoshop CC to determine the RGB level for each photograph. We selected the area of the petri dish to determine the RGB levels. The greater the total value of R and G, which is yellow, the more bacteria is there.

Below image shows the RGB levels of 1A. To get the RG value of 1A, simply add up the R and G values, which in this case is 162 and 157 respectively. The RG value of 1A is 162 + 157 = 319. Screen Shot 2017-03-04 at 19.49.19.png


  1. We then plot 4 graphs. Two graphs (Set A and B) for bacterial count vs washing time and another two (Set A and B) graphs for GR value vs washing time. With this, we can compare the graphs to determine whether the washing time has an impact on the growth of bacteria.

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