1. By: 1. Teo Boon Boon 2. Khor Mei Ann 3. Ooi Shu YU

2. Introduction ECSHERICHIA COLI Benefits of E. coli  improve immune response  boost digestion  prevents the accumulation of waste in the body Disadvantages of E. coli  cause illness E. coli can be eliminated by using detergent or through food that has microbial effect

3. GARLIC (allium sativum)  good antimicrobial agent which acts effectively against many gram-negative and gram-positive bacteria  enzyme alliinase will be released to catalyse the formation of sulfenic acids  sulfenic acids react with each other to form a thiosulfinate known as allicin  allicin functions as an antimicrobial agent

4. Materials and Methods Apparatus  Micropipette, pestle and mortar, conical flasks (100ml, 250ml), universal bottle, incubating loop, measuring cylinder, micropipette tips, microcentrifuge tips, scott bottle, weighing boat, glass rod, spatula, cotton bud, autoclave bag, beaker (100ml, 250ml), aluminium foil, hockey stick, pasteur pipette, petri dish, parafilm, filter paper, filter funnel, autoclave tape.

5. Materials  Electronic balance, fridge, incubator, autoclave, microcentrifuge, Bunsen burner, igniter, sealer. Chemical  Distilled water, nutrient broth, nutrient agar.

6. Procedure Part A: Isolation of Escherichia coli 1. Swab the water from the toilet bowl by using sterilized cotton bud. 2. Place the sample in the sterilized universal bottle containing nutrient broth. 3. Streak the plate by using inoculating loop. 4. Incubate the culture overnight for 16 hours at 37 °C.

7. Part B: Preparing The Garlic Juice 1. Measure 3.00g of the garlic by using electronic balance. 2. Mash the fresh garlic by using the mortar and pestle. 3. Add 5.0mL of distilled water to get fresh garlic extract juice. 4. Repeat the above steps by using 6.00g, 9.00g, 12.00g, and 15.00g of garlic.

8. Part C: Effect of Various Mass of Garlic on Antimicrobial Effect on the Culture 1. Culture the colony in 60mL nutrient broth. 2. Incubate the colony overnight. 3. Aliquot 10mL culture from the incubated culture. 4. Repeat step 3 for 4 times. 5. Add 5 mL of garlic juice prepared from each set in Part B into each of the culture. 6. Shake the mixture gently. 7. Incubate all of the mixture for 3 days.

9. Part D: Cell Counting 1. Label the petri dishes with A, B, C, D and E by using marker pen. 2. Place the petri dish A on the gridded background. 3. Count the cell in each grid move in a methodical pattern through the entire cell. 4. Mark the counted colonies on the back of the petri dishes by using marker pen. 5. Repeat step 2 to 4 for petri dish B, C, D and E. 6. Record down all the counting in Table 1.

10. VARIABLES  Manipulated variable: Mass of the garlic extract  Responding variable: The colony counting of Escherichia coli in petri dish  Constant variable: The temperature of the Escherichia coli, pH value of Escherichia coli, the volume of distilled water, the volume of nutrient broth