Prevalence and persistence of select foodborne pathogens in a mid-atlantic turkey processing facility

by 1980- Stam, Christina Nicole

Stam, Christina Nicole. Prevalence and Persistence of Select Foodborne Pathogens in a mid-Atlantic Turkey Processing Facility. (Under the direction of Dr. Lee-Ann Jaykus). Listeria monocytogenes, Salmonella and Campylobacter combined are responsible for the majority of foodborne disease hospitalizations and over 1200 deaths annually in the U.S. alone. Although raw poultry has been identified as a source of these pathogens, most microbiological studies have focused on broilers with little attention given to turkey processing. The purpose of this research was to investigate the prevalence of select pathogens (L. monocytogenes, Salmonella spp., and Campylobacter spp.) and microbiological indicators (Enterococcus spp.) in the turkey processing environment. Environmental samples were collected in one Southeastern processing facility using swab methods at two month intervals over a period of 14 months. Samples were taken from conveyors, drains, walls and various food contact surfaces. Isolation and identification of bacteria was done using the USDA-FSIS Microbiology Laboratory Guidebook protocols. The prevalence of contamination was 11.5%, 7.4%, and 0.4% for L. monocytogenes, Salmonella, and Campylobacter, respectively. Enterococcus spp., an environmental indicator of fecal contamination, were isolated from over > 75% of the samples screened. Salmonella isolates were typed using pulsed-field gel electrophoresis (PFGE) and Enterococcus isolates were speciated by PCR with antibiotic resistance profiles characterized using the SensiTitre system. A diverse set of relatively nonpersistent Salmonella strains were obtained from the processing environment, as evaluated by PFGE. Thirty-nine percent of the Enterococcus isolates were speciated as E. faecium and 55% were E. faecalis. Both E. faecalis as E. faecium strains were susceptible to most antibiotics of human clinical relevance. Thirty-three L. monocytogenes strains were screened for their biofilm formation capabilities using a microtiter well assay. None of the strains formed a biofilm in monoculture; however, sixteen of the strains were able to form a biofilm in the presence of another organism. Data collected in prevalence studies such as this one can help processors identify contamination frequency and sites in an effort to control resident pathogenic bacteria in the processing environment.