Effect of garlic and mint on bacterial growth

Independent: Presence garlic/mint

Dependent: Zone inhibition around disc

Control: Conc. plant material Lawn bacteria on petri dish Contamination petri dish by other microbes Same vol. plant material on each disk

Method: Make plant extract, crush 3g plant material w/ 10cm3 industrial denatured alcohol. Shake 10mins. Pipette 0.1cm3 extract onto sterile paper discs. Allow draw on sterile petri dish. Meanwhile label agar plates with date & split into 3 sections. 2 for each type of plant extract & 1 for control with distilled water on disc. Place 1 disc of each extract in each quadrant agar plate, close & tape w/ hazard tape. Leave incubate overnight & observe zone of inhibition.

Outcome: Control discs completely covered w/ bacteria, some plant extract create larger zone inhibition than others, meaning more effective at lower conc.

Evaluation issues: Growth unwanted microbes on agar plates due bad aseptic techniques. Not shaking extract enough ensure enough active ingredient. Inconsistency when add plant extract to paper discs. Contaminating controls Using wrong species bacteria for lawn.

Method