Award Date

May 2016

Degree Type

Thesis

Degree Name

Master of Public Health (MPH)

Department

Environmental and Occupational Health

First Committee Member

Mark Buttner

Second Committee Member

Patricia Cruz

Third Committee Member

Timothy Bungum

Fourth Committee Member

Vernon Hodge

Number of Pages

52

Abstract

When food establishments make ice for consumption, it is important to use water free of pathogens and to employ hygienic practices. Freezing can reduce the number of culturable microorganisms present in water but does not eliminate them completely. Coliform bacteria are used as an indicator of water quality and are used to test for fecal contamination. The U.S. Environmental Protection Agency (EPA) establishes standards for drinking water, and has set a goal for zero total coliforms. Another commonly used tool to measure water quality is the heterotrophic plate count (HPC). The EPA limit for HPC is 500 colony forming units (CFU) per milliliter. The objective of this study was to determine the microbial contamination of ice at food establishments in Las Vegas, NV. Ice and water samples were collected from local food establishments and analyzed using EPA standard methods. A convenience sample was collected from 14 food establishments near the main campus of the University of Nevada, Las Vegas. Samples were processed and analyzed for the presence of E. coli, total coliforms, and HPC using culture analysis. A molecular method, Polymerase Chain Reaction (PCR) was also used to test for E. coli. A total of 19 of the 28 (67.9%) samples collected exceeded the EPA limit for HPC. Coliform and E. coli analysis showed 10 of the 14 ice samples (71.4%) contained coliforms, and two out of 14 (14.3%) ice samples also contained E. coli. The current methods for inspecting ice at food establishments are insufficient for determining microbial contamination. Contaminated ice can contain pathogens and is a public health concern. Further research should be conducted to reduce the public health risk of ice and drinking water contamination in food establishments.

Keywords

Coliform; Heterotroph; MI agar; R2A agar; Real-time polymerase chain reaction

Disciplines

Microbiology | Public Health

Language

English


Share

COinS