Identification of enterobacteriaceae on vacuum loaders in shell egg processing

Cleaning and sanitation are 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 used in shell egg processing to transfer nest run eggs to the processing line. Twenty cups were rinsed on each of 3 visits to both an off-line operation and a mixed operation. A total of 442 Enterobacteriaceae isolates were biochemically identified from vacuum loader cup rinses. The predominant genera isolated from the 2 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 18 genera were recovered from the 2 facilities, with 9 being present in both processing facilities. The findings of this study can be used in assessing the sources of bacterial contamination in egg processing and in developing more effective, targeted cleaning programs for processing equipment and facilities.