Date of Award

8-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

John J. Gaynor

Committee Member

Julian P. Keenan

Committee Member

Robert W. Meredith

Abstract

Standard microbiological methods were utilized to assess the microbial diversity and abundance in the hot dog water found in mobile food carts. Since we could not directly assay the water, we devised a method of washing hot dogs with sterile water to indirectly assess the presence of microorganisms both growing in the water and on the hot dogs. Plating on LB-agar and LB-agar supplemented with antibiotics was used to isolate microbes from hot dog water from randomly selected vendors in twenty-six Manhattan neighborhoods and the Bronx. In addition, five major hot dog brands were similarly tested as store-bought controls. As expected, on-street hot dog water contained culturable microbes, ranging from 0 to more than 1.25 x 105 Colony Forming Units (CFU’s) per hot dog (X = 8,000 CFU’s/hot dog). Control hot dogs had considerably fewer culturable microorganisms (from 0 to to 2.5 x 103 CFU’s per hot (X = 1,100 CFU’s/hot dog). We have also discovered antibiotic resistant bacteria at 5 of our 26 sites (20%), including Ampicillin, Chloramphenicol, Kanamycin and Tetracycline resistance. In addition, our data suggests a possible correlation between CFU’s and serving temperature of hot dogs. Those served at temperatures of 145 F or greater had a mean of 33.9 CFU’s/hot dog, whereas those below 145 F had a mean of 9,897 CFU’s/hot dog. PCR-based amplification using the 16S locus for DNA barcoding was utilized to identify isolated colonies. We identified 22 different microbial species in on-street hot dogs, and 10 different species in store-bought (control) hot dogs. In summary, the hot dog water microbiome is complex and shows greater diversity than that associated with control hot dogs.

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