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Title: Presence of Aerobic Microorganisms, Enterobacteriaceae and Salmonella in the Shell Egg Processing Environment

item Musgrove, Michael
item Berrang, Mark

Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/6/2008
Publication Date: 8/3/2008
Citation: Musgrove, M.T., Berrang, M.E. 2008. Presence of Aerobic Microorganisms, Enterobacteriaceae and Salmonella in the Shell Egg Processing Environment. International Association for Food Protection Proceedings. 47-48.

Interpretive Summary:

Technical Abstract: Sanitation is vital to providing safe, healthy food to consumers. Understanding the degree to which microorganisms persist on specific equipment or locations contributes to developing effective sanitation programs. Certain microbial populations may be used to determine areas within a processing plant that warrant an increased effort in achieving an acceptable level of sanitation. A survey of aerobic microorganisms (APC), Enterobacteriaceae and Salmonella contamination of 26 sites within a single commercial shell egg processing plant was conducted on two visits. Tank lids, nozzle guards, and the interior surface of the tank, spindles, brushes and belts along the processing chain, scoops, air filters, and floor drains were sampled using swabs moistened with 10 ml deactivating buffer. Samples were transported on ice to the laboratory. Each sample was stomacher blended and then duplicate plated onto plate count agar incubated for 48 h at 37oC and violet red bile glucose agar incubated overnight at 37oC to enumerate aerobic microorganisms and Enterobacteriaceae, respectively. Counts for each sample were converted to log CFU/ml and results from both visits were averaged together. Sponges for each sample were selectively enriched using conventional cultural media, incubation temperatures and times. APC levels ranged from 1.9 log CFU/ml for washer tank lid and post-wash spindles to 7.6 log CFU/ml for the pre-wash tank surface and floor drains. Enterobacteriaceae levels ranged from 0.0 log CFU/ml for wash tank nozzles, lids, post-wash spindles, and post-wash packer belt to 3.1 log CFU/ml for pre-washed egg accumulator belt, floor drains and 4.0 log CFU/ml for breaker egg diverter. Salmonella was recovered from floor drains, breaker egg diverter and breaker egg belt surfaces. High levels of APC and Enterobacteriaceae may not always provide an index of pathogen contamination but they can be used to determine locations within the processing environment where stricter hygiene is needed.