The Effects of Black Tea on the Growth

The kernels of dimmed teatimetime on the growth of E. coli bacteria cultures Kierstin Barker, genus Melissa Bischak, Jackie Tyszkiewicz, Errin En all folk 25, 2012 Abstract This study was carried out in order to investigate whether dusky tea has antimicrobic properties as stated in Steven Johnsons The speck Map. If tea does have antimicrobic properties, then it could back up in warding reach waterborne diseases. We believed that if black tea is steeped in change state water, then the substance of bacteria subject to this firmness of purpose would decrease. We expected to see no difference in the amount of bacteria exposed to the black tea origin.Tannic venomous, black tea, stewed water, and a tetracycline antibiotic were time-tested for their partition offs of suppression in order to determine disinfectant properties. Our results stated that tea does not contain tannic acid save does contain tannin and therefore does not have antimicrobic properties that cont ain tannic acid found on the results of this test. Introduction In the novel The Ghost Map, written by Steven Johnson, Johnson refers to the idea that tea has antimicrobial properties and that it could possibly have influenced peoples risk of contracting infectious diseases such as epidemic cholera (Johnson, 2006).Traditionally, people drank tea to improve blood flow, eliminate toxins, and to improve resistance to diseases (Dufresne and Farnworth, 2000). teatime has been shown to have a wide range of physiological and pharmacological feats such as having antimicrobial properties, inhibiting malignant cells, and simply leaving the drinker feeling refreshed (Hamilton-Miller, 1995). Black tea contains amounts of tannic acid.Tannic acid is a commercial type of tannin, which is a bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids and has antimicrobial properties which could possibly aid i n warding off waterborne diseases (Yildirim, 2000). Could some people in the city of capital of the United Kingdom really have been saved from the fatal cholera disease due to their preferred drink of tea? If tea actually does have antimicrobial properties, then it could possibly provide some explanation as to why some people were not affected by this waterborne disease as earnestly as others.So, our primary question is, Does black tea decrease the amount of live bacteria in a solution? In order to test this question, we have devised hypotheses and experiments to see if black tea actually does stunt bacterial growth and whether tannic acid helps aid in this process. While making observations, exploitation questions, designing an experiment to test hypotheses, and analyzing data, we also want to demonstrate our proficiency in using the scientific method throughout this study. We believe that if black tea is steeped in stewed water, then the amount of bacteria exposed to this so lution will decrease.We expect to see no difference in the amount of bacteria exposed to the black tea solution. If we are equal to accept our alternative hypothesis, then the claims that Steven Johnson makes in The Ghost Map could be plausible and tea with tannic acid could have possibly helped ward off waterborne diseases during this particular outbreak in London. By testing antibiotic, tannic acid, and black tea solutions on prepared agar plates covered in E. coli bacteria, we predict to observe the different effects that each solution emits based on the district of prohibition for each type of solution.Materials and Methods This experiment was carried out on September 11, 2012. In order to carry out such an experiment, many different materials were used. Two 200 mL beakers were each filled with 200 mL of deionized water. Using a Bunsen burner, both beakers of water were het up(p) until boiling at 100? C. Three agar plates were prepared with 100 microliters of E. coli bacteri a. This amount was measured using a micropipette. The bacteria were then spread around the entire surface area of each plate. each(prenominal) agar plate was then labeled fit inly (figure 1).Plate 1Plate 2Plate 3 Antibiotic (Tetracycline- 30 micrograms/disc) Antibiotic (Tetracycline- 30 micrograms/disc) Boiled water Boiled water Tea Tea 0. 5% tannic acid 0. 5% tannic acid 2% tannic acid 2% tannic acid Figure 1 Labeling of agar plates. The arrows represent the side in which the solution was placed. for each one half of the plate contained 3 discs doused with the appropriate solution. After the water was boiled, a black tea radix was then placed into one of the beakers and steeped for 4 minutes. This time was monitored using a stopwatch.After the tea had been steeped, 6 discs were plunge into the tea solution and then placed in the appropriate agar plate (plate 3). The discs were fairly partake distances apart. The same procedure was done with the other beaker of boiled water, t he antibiotic, and the different percentages of tannic acid. A total of 6 discs were placed on each plate (ex 3 dipped in boiled water, 3 in antibiotic in plate 1). These agar plates with added discs were then placed in an incubator set to 37? C for 48 hours and then placed in a refrigerator at 4? C.After the deal out time, the agar plates were taken out of storage and the bacterial reactions to the different solutions were observed and the regularise of inhibition on each disc was measured in centimeters using a caliper measuring tool. Results T fitted 1. median(a) diameter in centimeters of the zone of inhibition of the discs soaked each solution. Diameter of Zone of Inhibition answer Average (cm) Boiled body of water 0. 0 Black Tea 0. 0 Tannic caustic (0. 5%) 0. 27 Tannic Acid (2%) 0. 63 Antibiotic 1. 0 Table 1. Average diameter in centimeters of the zone of inhibition of the discs soaked each solution.Diameter of Zone of Inhibition Solution Average (cm) Boiled Water 0. 0 B lack Tea 0. 0 Tannic Acid (0. 5%) 0. 27 Tannic Acid (2%) 0. 63 Antibiotic 1. 0 After measuring the zone of inhibition for each type of solution, we were able to conclude which solution had the most antimicrobial properties based on its zone of inhibition. The solution that had the most antimicrobial properties (stunted the growth of the bacteria the most) would have the greatest average zone of inhibition. According to our data, the solution with the greatest zone of inhibition was the antibiotic (table 1).This parsimony was then compared to the rest of the solutions activity towards the bacteria. The higher tannic acid concentration had a greater zone of Figure 2. Average zone of inhibition in centimeters of each solution tested. For tannic acid solutions, the percentage in the parentheses is the concentration of the tannic acid. Figure 2. Average zone of inhibition in centimeters of each solution tested. For tannic acid solutions, the percentage in the parentheses is the concentr ation of the tannic acid. inhibition but a lower zone of inhibition than the antibiotic (table 1).Therefore, the more concentrated the tannic acid is, the greater the zone of inhibition. The black tea reacted to the bacteria in the same way as our boiled water control. These both had a zone of inhibition of zero. To bring out reinforce the differences in zones of inhibition, a saloon graph was constructed (figure 2). Through this we were able to see the varying zone of inhibition and therefore could conclude the amount of bacteria growth on the different plates based on which solution was used. Discussion In this lab, we tested black tea in order to see if it would produce a zone of inhibition in response to E. oli bacteria. What we observed after applying discs to our agar plates was that no apparent zone of inhibition on the tea discs was reached. Our control of boiled water had the same response to the E. coli as did the tea. The tetracycline antibiotic contained the greatest z one of inhibition because it was our control and was known to have antimicrobial properties. Tetracycline is primarily bacteriostatic and exerts its antimicrobial effect by the inhibition of protein synthesis (Anderson, 2012). The tannic acid also had antimicrobial properties based on the zone of inhibition.The greater amount of concentration, the more of an effect it had on stunting bacteria growth. Because the reaction to the bacteria in the tea and water solutions was similar and the reaction to the bacteria in the tea and the antibiotic was so different, this showed that tea does not have any antimicrobial properties based on this experiment. Because of the difference in reactions in the tannic acid versus the tea solutions, tea does not contain tannic acid or the amount of tannic acid in tea is so little that it does not produce a significant effect on bacteria.We expected to see no difference in the amount of bacteria exposed to the black tea solution. Therefore, we accepted o ur null hypothesis. We must reject our alternative hypothesis because no zone of inhibition was observed on the tea agar plate. We also did this experiment to see if tannic acid had and the black tea had a similar reaction to the bacteria. We observed that the results actually worked in reverse the tea showed no significant signs of inhibition while the tannic acid did. With further research, we were able to conclude that tea does not contain tannic acid, but it does contain tannin (Richardson, 2012).Tannic acid is a form of commercial tannin and has antimicrobial properties, but it is not found in tea (Post, 2009). Through further research we were able to find a similar experiment that received positive data to support that tea has antimicrobial properties. In this experiment, they attempted to describe the synergistic antimicrobial activity of tea and antibiotics against enteropathogens. Antimicrobial activity of boiled water tea extract and organic solvent extract were studied ag ainst Salmonella typhimurium to determine minimum inhibitory concentration.Both green tea and black tea extracts effectively inhibited the growth of S. typhimurium and E. coli (Tiwari et al. , 2005). The difference in this experiment was that they added another alternative to test the tea the tea was steeped in water at room temperature and in boiled water. According to their results, the zone of inhibition was greater in the tea at room temperature than the boiled water and the E. coli had a lower zone of inhibition than the S. typhimurium (Tiwari et al. , 2005). Not adding these factors into our own experiment could have make a significant difference in our figures and the zones of inhibition.Some areas of human error could have been that the tea was steeped for too picayune of a time to show any significant results or the forceps that handled the discs were not adequately sterile. Black tea did not have tannic acid as previously thought. Through research we were able to better our knowledge and accept our null hypothesis. Tea does have tannins which can be defensive compounds that counteract bacteria and fungi by interfering with plants surface proteins (McGee, 2006). This could have aided in the preservation of health during cholera outbreaks, but tannic acid was not a culprit in this investigation.Tea did not show any significant zone of inhibition and therefore does not have significant antimicrobial properties against E. coli bacteria according to this experiment. Literature Cited Dufresne, C. and Farnworth, E. 2000. 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