Submitted to: International Journal of Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/15/2005
Publication Date: 12/31/2005
Citation: Jones, D.R., Musgrove, M.T., Caudill, A.B., Curtis, P.A., Northcutt, J.K. 2005. Microbial quality of cool water washed shell eggs. International Journal of Poultry Science. 4(12):938-943. Interpretive Summary: Cool water washing of shell eggs has the potential of assisting in the quick reduction of internal egg temperature post-processing. Fast reduction of internal egg temperature has been identified as an important step in reducing the ability of potential Salmonella Enteritidis organisms present from multiplying. Furthermore, the faster an egg is cooled, the greater the egg quality. A study was undertaken to determine the microbial quality of shell eggs processed at cool temperatures. The naturally occurring aerobic bacterial levels were lowest for eggs processed according to the current USDA warm water recommended temperature. Eggs processed in a combination of warm (48.9C) and cool (23.9C or 15.6C) also had lower levels of aerobic organisms present on the shell surface during cold storage. All temperature schemes examined were able to remove inoculated Salmonella Enteritidis to the same degree. Therefore, it is recommended that commercial application studies be conducted to determine if cool water washing can beneficially affect microbial populations associated with eggs and egg quality when conducted on the larger scale.
Technical Abstract: A study was conducted to examine the effects of cool water washing on the microbial quality of shell eggs. Six dual tank wash water temperature schemes were examined for their ability to reduce naturally occurring aerobic bacteria and artificially inoculated Salmonella Enteritidis (SE). The wash water schemes were: T1 – 48.9C; T2 – 48.9C, 23.9C; T3 – 48.9C, 15.6C; T4 – 23.9C; T5 – 15.6C; and T6 – 23.9C, 15.6C. All wash water tanks were maintained at 10.5-11.5 pH throughout all replicates of the study. Eggs were exposed to the wash water temperature schemes in a pilot egg washer with recirculating wash water tanks. The total amount of time eggs were exposed to the wash water combinations was 60 s. All eggs were sprayed with a 48.9C, 200 ppm chlorine rinse solution. Eggs were stored and sampled for 9 wks. External aerobic populations were lowest for T1 (typical U.S. wash water configuration), followed by T2 and T3. The greatest level of aerobic surface contamination was found in T5 eggs. All treatments reduced SE levels in a similar manner as detected in shell and membrane emulsion and egg contents pools after enrichment. Commercial application of cool water shell egg processing will be investigated to determine the potential of this technology to enhance the safety and quality of shell eggs.