The Truth About Tea

1. The Truth About Tea The Antibacterial Effects of Green Tea: Bottled vs. Brewed

2. Background Research • Green tea has been shown to help with heart disease, oral health, arthritis, weight loss, stress, flu, food poisoning, colds, and other bacterial illnesses • It can also help promote helpful bacteria in the intestines • Sweetened, flavored, bottled, and old green teas have been shown to retain less antibacterial effects as they are very processed • Escherichia coli (E. coli) • Gram negative • Bacteria found in intestines of warm blooded animals and people • Causes food poisoning and can be from consuming undercooked or raw meat and vegetables, water, or anything that comes in contact with animal manure • Can cause diarrheaand eventually HUS/kidney failure • Most documented outbreak of O157:H7 • Similar to Salmonella • Streptococcus mutans • Gram positive • Bacteria found in teeth and mouth area • Creates acid which causes tooth decay, and also damages gums and roots • Feeds on refined carbohydrates in milk, sugar, fruit, etc.

3. Question • Which type/brand of green tea has the most antibacterial effects?

4. Hypothesis • The brewed green tea made from Chinese tea leaves will have the most antibacterial effects.

5. Materials • Brewed Chinese green tea • Trader Joe’s unsweetened bottled green tea • AriZona sweetened honey ginseng bottled green tea • Just Tea unsweetened bottled green tea • Gold Peak unflavored bottled green tea • Sterile water • Twenty-four sterile paper disks • Six Petri dishes with tryptic soy agar • Six empty Petri dishes • Streptococcus mutanspurchased from a catalog • Escherichia colipurchased from a catalog • Ruler (in centimeters) • Sterile tweezers • Incubator • Sterile swabs • Goggles • Lab coat • Gloves • Permanent marker • Tape

6. Procedure • Petri dishes with agar were labeled with three tests for each type of bacteria, and type of tea on outside • Empty Petri dishes were each filled with one of the types of tea and sterile water, and the sterile disks were put in to soak • Sterile swabs were used to spread E. coli over its three Petri dishes • One disk soaked in each type of tea was put into each test of E. coli • The Petri dishes were incubated at 37 °C for approx. 48 hours, then the zones of inhibition were observed • Freeze dried strep mutans cultures were hydrated using sterile technique, and the bacteria was incubated for approx. 24 hours • Steps 2 – 5 were repeated for strep mutans tests

7. Variables • Independent • The types of green tea; the types of bacteria • Dependent • The size of the zones of inhibition • Control • The sterile water tests • Constants • The two different types of bacteria, the types of green tea and water, the length of incubation

8. Data (1)

9. Data (2)

10. Data (3)

11. Possible Sources of Error • For the E. coli test, the time between when the brewed green tea was made and when it was tested was larger than in the strep mutans test • In the strep mutans test, the zones of inhibition were very faint and may have been inaccurately measured for any of the teas

12. Conclusion • All teas except for AriZona had at least a small amount of antibacterial effects • The flavored, sweetened, more processed teas had less effects • Because of the range of data for brewed green tea, it can’t be said whether it had a greater effect than any others except AriZona • The hypothesis was rejected – Trader Joe’s had the most effects overall and was very consistent in the data, but may be slightly more effective on E. coli • Unsweetened, unflavored bottled green tea or brewed green tea from loose leaves are still the best choices

13. Works Cited • About E. coli. (2011). Retrieved from Marler Clark LLP, PS website: http://www.about-ecoli.com/ • All about antioxidants. (n.d.). Retrieved from AriZona Beverage Co. website: http://www.drinkarizona.com/‌index_national.html#health_anti_ox • Baker, S. L. (2010, August 17). Scientists discover how polyphenols in green tea may protect health of diabetics. Retrieved from Natural News Network website: http://www.naturalnews.com/‌029496_polyphenols_green_tea.html • Bottled green tea and canned drinks: Why more harmful than healthy. (2006-2010). Retrieved from http://www.amazing-green-tea.com/‌bottled-green-tea.html • Chinese tea health benefits. (2005-2010). Retrieved from http://www.goldenteahouse.com/‌health_benefits.php#bac • Cold tea vs hot tea health benefits: How long can you keep or steep? (2006-2010). Retrieved from http://www.amazing-green-tea.com/‌cold-tea.html • Compestine, Y. C. (2000). Introduction. In Cooking with green tea (pp. 2-3). New York, NY: Avery Books. • Cup of green tea to keep the bacteria away. (2007, January 16). ScienceDaily. Retrieved from http://www.sciencedaily.com/‌releases/‌2007/‌01/‌070116132946.htm • Green tea. (2007). In B. Baver (Ed.), Mayo clinic book of alternative medicine (p. 56). New York, NY: Time. • Herbal remedies. (2010). Retrieved from Resort health products website: http://www.resorthealth.com/‌herbs/‌green_tea.html • Lash, R. (2007). The legend of green tea keeps a-growin. Discover. Retrieved from http://discovermagazine.com/‌2007/‌oct/‌the-legend-of-green-tea-keeps-a-growin/‌?searchterm=health%20&%20medicine%20nutrition%20te • Learn all about the history of green tea. (2010). Retrieved from Adagio Teas website: http://www.green-teas-guide.com/‌history-of-green-tea.html • LIPTON® green tea with citrus flavor. (2010). Retrieved from Unilever website: http://www.liptont.com/‌our_products/‌iced_tea/‌ice_green_citrus.aspx • Strep mutans. (2010). Retrieved from http://www.dentist.net/‌strep-mutans.asp • Tai, J. (2006-2010). The truth about tea: A t-volution is quietly steeping away. Retrieved from http://www.amazing-green-tea.com/‌index.html Thank you!