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Bacteria on Restaurant Lemon Wedges

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Presentation on theme: "Bacteria on Restaurant Lemon Wedges"— Presentation transcript:

1 Bacteria on Restaurant Lemon Wedges
What’s On My Water? Bacteria on Restaurant Lemon Wedges

2 Problem Are restaurant lemon wedges free from bacteria? If not what is it that humans are ingesting?

3 Background Information
In 2008 Anne LaGrange Loving conducted an experiment with lemon wedges at restaurants to determine what exactly is on them 53 out of 76 lemons that she swabbed were infested with bacteria Lemon pulp is acidic; it registers with a pH of 4. This could possibly kill bacteria Coliform bacteria is found in warm-blooded animals Pathogenic bacteria tags along closely to coliform bacteria Coliscan Easy Gel plates shows coliform bacteria as either blue or pink colonies

4 Hypothesis If lemon wedges from restaurants are tested for bacteria and coliforms and are compared to clean lemons, the restaurant lemons will have bacteria present.

5 Materials 15 lemon wedges: 10 from 2 restaurants ; 5 from a control lemon 30 Coliscan Easy Gel plates 30 cotton tipped sterile swabs Bunsen burner Gloves, lab coat, protective glasses

6 Procedure Lemons were collected from 2 restaurants
Lemons were swabbed using aseptic technique Swabs were inserted and swirled in the liquid form of Coliscan Easy Gel Set dishes were placed in the incubator for 96 hours at 37⁰ Celsius Colonies were counted by using a grid. 8 sample blocks were counted, and the sum was multiplied by 4 All dishes were disposed by autoclave

7 Variables Control: clean washed lemon Independent: the restaurants
Dependant: the count of bacteria per wedge Constants: temperature of incubator, amount of time in incubator, area of swabbing




11 T-test between Restaurants and Control Lemon
Restaurant 1 and Control Rind Restaurant 2 and Control Rind

12 Conclusion “If lemon wedges from restaurants are tested for bacteria and coliforms and are compared to clean lemons, the restaurant lemons will have bacteria present.”- was supported No coliforms were found, so half of the hypothesis was rejected.

13 Sources of Error The incubator may have been opened for long periods of time thus causing a temperature change Some condensation was found on the plates In only one plate, spores of mold were found; this plate was discounted

14 Further Research A more comprehensive survey of restaurants
What exactly is on lemon wedges? What type of soap kills the most bacteria?

15 Works Cited Growth. (1999). Introduction to Bacteria [Fact Sheet]. Retrieved from University of Missouri- Saint Louis website: Instructions. (n.d.). Retrieved November 12, 2010, from Micrology Laboratories website: Media/‌Coliscan_Easygel/‌Instructions Loving, A. L., & Perz, J. (2007, December 1). Microbial flora on restaurant beverage lemon slices. Journal of Enviromental Health. Retrieved from rage+lemon+slices-a Morton, J. F. (n.d.). Lemon. Retrieved October 6, 2010, from Perdue University website: pH Panel. (n.d.). The pH Factor. Retrieved October 21, 2010, from Miami Science Museum database.

16 Works Cited Continued Reynolds, G. (2007, March 21). Bacteria effective against fresh cut fruit contamination. Food Production Daily. Retrieved from Safety/‌Bacteria-effective-against-fresh-cut-fruit- contamination Stone, A. H. (1966). Chemistry of a Lemon. Englewood Cliffs, New Jersey: Prentice Hall. Wassenaar, T., Dr. (2009, January 6). Food Safety [Virtual Museum]. Retrieved October 7, 2010, from Safety/‌food-safety.html

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