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1995 Special Awards Winners
State Science and Engineering Fair of Florida
April 5-7, 1995
Manatee Civic Center, Palmetto
Awards Given By The Florida Department of Agriculture and Consumer Services
Nicole Junelle Young
Awards Given By Florida Agriculture in the Classroom
Cassandra L. Quave
The researcher's purpose is to determine the effect of varied dosages of X-ray irradiation on the micro flora of raw ground beef.
The researchers' hypothesis is that the dosage of 120 Gy will eradicate all of the bacterial growth in the raw ground beef.
Collect 30 samples of gound beef. Emulsify the beef into a semi-liquid broth. lace the samples into 5ml test tubes. Add 20 drops (1ml) of low concentration saline solution to the tubes. Mix the tubes in a Vortex Genie Mixer. Remove 10 drops (1/2) ml of the broth and inoculate a blood agar plate. Subculture the plates. Place in the incubator. Monitor the plates for 48 hours then run identification tests on them. irradiate the samples at 4 dosages of 30 Gy, 60 Gy, 90 Gy, and 120 Gy. Repeat the culturing and identification procedures used for the control Use all proper safety procedures.
The researcher has found that the majority of the micro flora that inhibited the samples of raw ground beef consisted of a variety of gram-positive bacteria such as Staphylococci and Bacilli; the gram-negative Escherichia coli. Serratia Liquefaciens, Salmonella Enteritidis, and Hafnia Alvei. The most predominant bacterial strain was beta-hemolytic Staphylococci. The most noticeable difference in growth is shown after 30 Gy of irradiation. The growth remained fairly constant and low after 30 Gy, 60 Gy, 90 Gy, and 120 Gy.
The researcher's hypothesis proved to be incorrect. There was still a substantial amount of bacterial growth in the samples irradiated at 120 gy. Although these dosages did not eradicate all of the bacterial growth - there was still a large decrease of growth in most of the samples starting at 30 Gy.
Bradford, A. et al. "Too Fast Food: Bloody Diarrhea and Death from Escherichia coli 0157:H7" Clinical Microbiology Newsletter. 16 vols. No. 3. Reprinted by the U.S. Dept. of Health and Human Services, CDC. 1 February 1994 ed.: 17-19.
Martin, D.M. et al. "The Epidemiology and Clinical Aspects of the Hemolytic Uremic Syndrome in Minnesota." New England Journal of Medicine. 323 vols. Minnesota De pt. of Health. Reprinted by the U.S. Dept. of Health and Human Services, CDC. 25 October 1990 ed.: 1161-1167.
Synge & Reilly. "Possible Link between cattle and E. coli infection in a human." The Veterinary Record. 133 vols No. 20. 13 November 1993 ed.: 507.