Materials:
 

Procedure:
Prepare media:

• Melt nutrient agar deeps in a hot water bath.
• Pour 8 petri dishes of media.

• Divide each plate into 4 sections.
• Label 4 of the plates’ sections as 1, 2, 3, and C.
• Label the other 4 plates’ sections as 4, 5, 6, and C.

•  Take approximately 2 grams of each of the six spices.
•  One spice at a time, add 5 ml of distilled water and make a paste using the mortar and pestle.
• .Place 4 disks per sample into the paste and then transfer to a petri dish to dry  (WARNING:Make sure disks are dry prior to placing on agar).
•  Also, soak 8 disks in distilled water to use as controls.

•  Take the 4 known bacteria samples and spread 2 petri dishes with .25 ml of each sample(make sure the 2 plates contain sections 1, 2, 3, and C and 4, 5, 6, and C (Control).
•  Use the glass rod to make a proper lawn.

Incubating plates:
    Incubate plates at room temperature for 24 hours.

Recording results:

•  Make a table to record the zones of inhibition for each bacterium’s interaction with the spice.

 Measure the distance from the disk to the edge of the zone of clearing.

Data:
 

 
Inhibition of Bacterial Growth by Spice Extracts

Zone of Inhibition (in mm)	Bacillus subtilis	Staphylococcus epidermidis	Eschericia coli	Serratia marcescens
Control 1	0	0	0	0
Control 2	0	0	0	0
Curry	0	1	3	0
Red pepper, dried	0	1	3	0
Jalapeno, fresh	0	2	2	0
Garlic, fresh	14	0	10	1.5
Cinnamon	4	0	5	0
Oregano	0	0	2	0

Conclusion:

All spices tested exhibited varying degrees of inhibition of growth on some bacteria.  Four of the spices showed minimal or no inhibition of growth.  Garlic and cinnamon, however, demonstrated significant inhibition on B.subtilis and E. coli, with garlic showing a zone of inhibition two to three times greater tahn that of cinnamon.

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