Identification of Enterobacteriaceae on Vacuum Loaders in Shell Egg Processing

Authors: Jones, Deana; Musgrove, Michael

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/3/2008
Publication Date: 8/1/2008
Citation: Jones, D.R., Musgrove, M.T. 2008. Identification of Enterobacteriaceae on Vacuum Loaders in Shell Egg Processing. Poultry Science.87(8):1678-1681

Interpretive Summary: Shell egg processing plant sanitation programs have been shown to be somewhat ineffective in reducing microbial contamination on processing equipment and plant surfaces. A study was conducted to determine which organisms within the Enterobacteriaceae family were present on the vacuum loader cups in both off line and mixed operation facilities. Vacuum loader cups are utilized to transfer nest run eggs (transported from laying house to processing facility on egg flats) to the egg processing line. A total of 442 Enterobacteriaceae isolates from the combined facilities were identified in this study. The genera associated with egg spoilage isolated during the study include: Pseudomonas, Acinetobacter, Proteus, Aeromonas, Serratia and Citrobacter. The potential human pathogens of Escherichia, Klebsiella, Shigella, Yersinia, Aeromonas, Enterobacter and Leclercia were also isolated. While previous research has shown washed eggs to have very low incidence of Enterobacteriaceae contamination, care should be taken to remove these organisms from the processing environment to prevent potential product contamination. The results from the current study can be utilized to target cleaning and sanitation programs to reduce bacterial levels on processing equipment.

Technical Abstract: Cleaning and sanitation is paramount in food processing. Gaining an understanding of the microbial populations present in a processing facility can help in the development of effective and efficient cleaning. The current study was undertaken to gain a better understanding of the Enterobacteriaceae present on vacuum loader cups utilized in shell egg processing to transfer nest run eggs to the processing line. Twenty cups were rinsed on each of three visits to both an off line and a mixed operation. A total of 442 Enterobacteriaceae isolates were identified from vacuum loader cup rinses. The predominant genera isolated from the two facilities were: Enterobacter, Klebsiella, Escherichia, Citrobacter and Serratia. The primary organisms from the off line facility were: Klebsiella oxytoca, Enterobacter amnigenus 2 and Klebsiella pneumoniae. The isolates found in the greatest proportion from the mixed operation were Enterobacter cloacae and Klebsiella oxytoca. A total of eighteen genera were recovered from the two facilities with nine being present in both processing facilities. The findings of this study can be utilized to aid in the assessment of the sources of bacterial contamination in egg processing and to develop more effective cleaning programs for the processing equipment and facilitie