Food Science and Technology Department


Date of this Version



A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In partial Fulfillment of Requirements For the Degree of Master of Science, Major: Food Science and Technology, Under Supervision of Professor Jayne Stratton. Lincoln, Nebraska: November, 2010
Copyright 2010 Yulie E. Meneses


Salmonella is one of the leading causes of foodborne illness worldwide, and it is estimated that 1.4 million infections occur annually in the U.S. alone. The Premi®Test Salmonella (PTS), is a potential tool for rapid detection and identification of Salmonella serovars. The objective of this project was to evaluate the use of the PTS system as a serotyping tool to identify pork and poultry isolates obtained from vertically integrated operations and to characterize their antibiotic resistance. Two hundred isolates were evaluated. All isolates were serotyped using the traditional Kaufmann-White scheme and the PTS system. Among the isolates 63 different serotypes were represented, 36 of which were included in the PTS database and 27 were not present in it. CDC pulsed field gel electrophoresis protocol was used to characterize the relatedness among isolates and their antibiotic resistance was determined using the Kirby-Bauer disc diffusion test. Serotype identification using the PTS system was reproducible independently of the source (pork or chicken) or replication. Sixty three percent of the serotypes present in by the PTS database were successfully indentified as Salmonella and matched traditional serotyping. Thirty seven percent of the isolates were identified as Salmonella but did not match results from traditional serotyping. Close relatedness among isolates was not responsible (in most of the cases) for the mismatches between KW and PTS system from serotypes present in the data base. Tetracycline resistance was observed mainly in pork isolates (S. Anatum, S. Heidelberg, S. Mbandaka and S. Johannesburg). Two multidrug resistance patterns were detected in S. Typhimurium and S. Bovis –morbificans (G-AM-C and Te-G-AM respectively).