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 ProblemAre 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 them53 out of 76 lemons that she swabbed were infested with bacteriaLemon pulp is acidic; it registers with a pH of 4. This could possibly kill bacteriaColiform bacteria is found in warm-blooded animalsPathogenic bacteria tags along closely to coliform bacteriaColiscan Easy Gel plates shows coliform bacteria as either blue or pink colonies
4 HypothesisIf lemon wedges from restaurants are tested for bacteria and coliforms and are compared to clean lemons, the restaurant lemons will have bacteria present.
5 Materials15 lemon wedges: 10 from 2 restaurants ; 5 from a control lemon30 Coliscan Easy Gel plates30 cotton tipped sterile swabsBunsen burnerGloves, lab coat, protective glasses
6 Procedure Lemons were collected from 2 restaurants Lemons were swabbed using aseptic techniqueSwabs were inserted and swirled in the liquid form of Coliscan Easy GelSet dishes were placed in the incubator for 96 hours at 37⁰ CelsiusColonies were counted by using a grid. 8 sample blocks were counted, and the sum was multiplied by 4All dishes were disposed by autoclave
7 Variables Control: clean washed lemon Independent: the restaurants Dependant: the count of bacteria per wedgeConstants: temperature of incubator, amount of time in incubator, area of swabbing
11 T-test between Restaurants and Control Lemon Restaurant 1 and Control RindRestaurant 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 supportedNo coliforms were found, so half of the hypothesis was rejected.
13 Sources of ErrorThe incubator may have been opened for long periods of time thus causing a temperature changeSome condensation was found on the platesIn 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 CitedGrowth. (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/InstructionsLoving, A. L., & Perz, J. (2007, December 1). Microbial flora on restaurant beverage lemon slices. Journal of Enviromental Health. Retrieved from rage+lemon+slices-aMorton, 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 ContinuedReynolds, G. (2007, March 21). Bacteria effective against fresh cut fruit contamination. Food Production Daily. Retrieved from Safety/Bacteria-effective-against-fresh-cut-fruit- contaminationStone, 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