The Antibacterial Effects of Carrots, Garlic, Kale, and Broccoli on Escherichia Coli

     This experiment tested the antibacterial effects of carrots, garlic, kale, and broccoli on Escherichia coli; whether or not they prohibited the growth of the bacteria, and which one was the most effective in doing so.

     These vegetables were juiced and tested along with various extracts or supplements (independent variable) and their resistance to the E. coli was meausured in millimeters (dependent variable). The hypothesis was "if carrots, broccoli, kale, or garlic possess antibacterial properties or agents, then they can cease or resist the growth of E. coli bacteria, and carrots will have the greatest effect because they contain polyacetylenes, which protect it from pests, diseases, fungi, and bacteria."

     Using the disc diffusion method, small discs were impregnated in the prepared solutions, then placed on nutrient agar that had been labeled into different sections for each solution and swabbed with E. coli. The petri dish was incubated at 37 degrees for 45 hours. If the solution was adequate, then a clear ring surrounds the disc, and no ring meant no resistance. This 'ring' is called the zone of inhibition. 

     The results revealed that juiced garlic is the most effective and resistant to the E. coli. The average diameter was 31 millimeters for it. The rest of the solutions either had rings that were not visible unless observed under a magnifying glass, or had no rings at all. This experiment demonstrates an alternative to man-made medicine; without the unwanted side effects, and that natural substances can be beneficial and as effective.

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