Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2007
Publication Date: 7/28/2008
Citation: Jones, D.R., Musgrove, M.T. 2008. Assessment of Microbial Contaminants Present on Vacuum Loaders in Shell Egg Processing Facilities. Journal of Food Safety.28(3):346-354.
Interpretive Summary: Vacuum loader cups have previously been determined to be reservoirs for high bacterial levels in shell egg processing facilities. The current study was conducted to determine the prevalence of pathogens on the cup surface. High levels of aerobic bacteria were found again and Enterobacteriaceae levels recovered were higher than those previously reported. Campylobacter and Salmonella were both recovered, but at low prevalence (1.6% and 3.3%, respectively). Salmonella isolates were determined to be S. Anatum and S. Heidelberg. A high prevalence of Listeria was detected (72%). Isolates were determined to be L. innocua (98.8%) and L. monocytogenes (1.2%). Findings of this research can be utilized to develop more effective cleaning and sanitation procedures for vacuum loader cups in shell egg processing facilities.
Technical Abstract: Previous studies have shown vacuum loader cups in shell egg processing facilities to be a reservoir of high levels of bacteria. This study was conducted to determine the prevalence of pathogens on the surface of the vacuum loaders cups. An off-line and a mixed operation shell egg processing facility were sampled three times each (weekly). Twenty vacuum loader cups were randomly rinsed with sterile saline each visit. Total aerobic populations and Enterobacteriaceae were enumerated and the prevalence of Salmonella, Campylobacter and Listeria was determined. Aerobic populations were similar to those previously reported (~5 log cfu/mL), being greatest in the mixed operation. Enterobacteriaceae levels were greater that those previously reported (2.5 log cfu/mL) and were higher in the off-line facility. Campylobacter was detected in 1.6% of the samples. Salmonella was detected in 3.3% of the samples with the isolates being S. Anatum and S. Heidelberg. There was a high incidence of Listeria (72%). Biochemical tests confirmed isolates to be L. innocua (98.8%) and L. monocytogenes (1.2%). Identification of the populations present on the cup surface will allow for a more targeted approach to the development of cleaning and disinfection programs.