Microbiological contamination of packer head brushes in United States commercial shell egg processing plants

Authors: Musgrove, Michael; Jones, Deana

Submitted to: European Poultry Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/14/2006
Publication Date: 9/11/2006
Citation: Musgrove, M.T., Jones, D.R. 2006. Microbiological contamination of packer head brushes in United States commercial shell egg processing plants. European Poultry Conference Proceedings.p.565.

Interpretive Summary:

Technical Abstract: In the United States, eggs are washed, checked for cleanliness, defect eggs are culled, and are then packed into cartons or flats based on weight. One of the last parts of egg washing machinery to come into contact with the eggs prior to packaging is packer head brushes. A sanitation study of shell egg processing plants reported aerobic microorganisms and Enterobacteriaceae could be recovered from these brushes. Packer head brushes (14) were sampled on three visits to a commercial shell egg processing plant. Sterile gauze pads were moistened with 10 mL of phosphate buffered saline (PBS) and wiped across the surface of the brushes before being placed on ice and transported back to the laboratory. Aerobic microorganisms and Enterobacteriaceae were directly enumerated from each sample while typical enrichment methodologies were performed for Salmonella, Listeria, and Campylobacter. Aerobes and Enterobacteriaceae were detected on every sample and population levels averaged 4.9 and 1.7 log CFU/mL, respectively. Salmonella was recovered from a single sample during one visit, Listeria was recovered from a single sample on two of the visits, and Campylobacter was recovered from a single sample on one visit. On each of the 3 visits, eggs that had been washed and packaged were collected from 2 of the 14 packer head lanes (randomly selected) and analyzed for the five microbial populations. While aerobes and Enterobacteriaceae were recovered from egg shells (2.9 and 0.2 log CFU/mL, respectively), none of the pathogens were recovered from these samples. Pathogen populations were only occasionally recovered from brushes and were not demonstrated to contaminate washed eggs. However, these data suggest that packer head brush sanitation could be improved.