1. The antimicrobial effect of garlic extract on Escherichia coli.

2.   LEE KE YIN  LIM KHAI LI  LIAW SZE YING Present by:

3.   To study the antimicrobial effects of garlic extract on the growth of Escherichia coli (E.coli). Purpose

4.   The longer the time taken for garlic extract mix with the environment of Escherichia coli (E.coli), the lesser the amount of the bacterial colonies Hypothesis

5. I NTRODUCTION

6.   Food borne pathogen and found in human’s intestine and animals.  Most E.coli are harmless but some strains of E.co li like E.coli 0157:H7 can lead severe illness such as bloody diarrhea and vomiting.(Mayo Clinic Staff,2014.) Escherichia coli(E.coli)

7.   Mostly human easily get the E.coli 0157:H7 through eating food like meat or drinking the unpasteurized milk.(Department of Health,2006.) Escherichia coli(E.coli)

8.   E.coli can killed by detergent or food containing antimicrobial effects such as ginger or garlic. Figure 1: E.coli(Escherichia coli)(Centers of disease Control and Prevention,2015) Escherichia coli(E.coli)

9. Figure 2: The E.coli bacterium (The Power,2011)

10.  Garlic

11.   Garlic is known as allium sativum act as anti-bacterial properties to kill bacteria.  Usually be a traditional medicine treatment in various forms of infections. Garlic

12.   Anti-bacterial properties of garlic is form the sulphur-containing organic compounds.  The number of sulphur atoms increase,the antimicrobial effects increases. Garlic

13.   Organosulfur compounds in the garlic can penetrate the cell membrane of the bacteria.  It combines with specific in the garlic enzyme or protein to alter the structure of pathogen.(Compound Interest,2014)  Organosulfur compunds can classified to two classes: y-glutamylcysteines and cysteine sulfoxides in garlic. Garlic

14.   Allylcysteine sulfoxide (alliin) is almost 80%of the cysteine sulfoxides in the garlic. Figure 3 : Structure of Alliin(The garlic-center,2014) Garlic

15.   Formation of sulfenic acids is catalyzed by alliinase enzyme from cysteine sulfoxides. Figure 4 : Sulfenic-acid-2D (Lookfordignosis,2014) Garlic

16.   Sulfenic acid will react with another to form compound called thiosulfinates.  Alliin resulting sulfenic acids react with each other to form a thiosulfinate is known as allicin. Figure 5: Structure of Allicin (The garlic-center,2014) Garlic

17.   S-allylcysteine is water-soluble organosulfur compounds, this are formed from y-glutamylcysteine with incubation of garlic extract. Figure 6:Structure of S-allylcysteine (Chemnet,n.d.) Garlic

18.   Allicin is as an antimicrobial agent in the garlic.  Allicin is break down to form fat-soluble organosuflur compounds.  Diallyl disulfide(DADS), Diallyl trisulfide(DATS), and Diallyl sulfide (DAS) are the substance in the organosulfur compounds. Garlic

19.  Figure 7 : The Organosulfur Compounds Derived From the Decomposition of Allicin. (Higdon.J,2005)

20.   5 nutrient agar plate  Cotton bud  10ml nutrient broth  Garlic  Escherichia coli (E.coli). Materials

21.   Micropipette  Pestle and Mortar  Conical flask  Universal bottle  Inoculating loop  Measuring cylinder. Apparatus

22.  Part A: Isolation of Escherichia coli (E.coli). 1. Swab the water from the toilet bowl by using sterilized cotton bud. Procedure Cotton bud

23.  Procedure(Part A) 2. Place the sample in the sterilized universal bottle. 3. Streak the plate by using inoculating loop. Cotton bud Universal bottle Inoculating loop Agar plate

24.  4. Incubate the culture overnight for 16 hours at 37oC. Procedure(Part A) Culture Conical flask

25.  Part B: Preparing the garlic juice. 1. Measure 10g of the garlic by using electronic balance. Procedure Garlic

26.  2. Mash the fresh garlic by using the mortar and pestle to get fresh garlic extract juice. Procedure(Part B) Garlic

27.  3. Measure 5ml of garlic extract by using measuring cylinder and pour into test tube. Procedure(Part B) Garlic extract

28.  Part C: Effect of the garlic juice on the culture 1. Take a single colony of Escherichia coli (E.coli) from the streaked plate by using inoculating loop then put into 10ml of nutrient broth. Grow it overnight at 37oC to make a culture. Procedure Agar plate with E.coli

29.  2. Add 5 ml of the garlic juice into the culture and incubate for 1 hour. Procedure (Part C)

30.  3. Label the agar plate A, B, C, D, and E by using marker pen. Procedure(Part C)

31.  4. After 1 hour, 1 ml of the culture is aliquot to the agar plate A by using the micropipette. Repeat at intervals of 1 hour over 5 hours. Procedure(Part C)

32.  5. By using the spread plate method, the agar plate is put overnight at 37oC. micropipette Culture Agar plate

33.  Part D: Cell counting 1. Place the agar plate A on the gridded background. Procedure Agar plate

34.  2.Count all the cell in each grid cell, move in a methodical pattern through the entire cell. 3.Mark the counted colonies on the back of the agar plate by using marker pen. 4.According with agar plate B, C, D,and E. Procedure (Part D)

36.  4. Record down all the counting in table 1. Procedure(Part D) Time taken for E.coli to grow Amount of E.coli in agar plate 1 2 3 4 5

37.  THE END