Abstract
An evaluation of methods for monitoring the quality of water used to wash eggs at grading stations was undertaken to improve maintenance of bacterial viability during overnight sample transport. Bacterial content of samples at analysis would then better reflect conditions at the time eggs were washed. The interactive effects of temperature and the highly alkaline water conditions upon viability were the subjects of this study. Nine transport methods were examined for their efficacy in recovering total and coliform bacteria from recycled water used to wash eggs, and these were compared with samples analyzed at two commercial egg grading stations. Samples were shipped under test to the laboratory for analysis the following day. The survival of Staphylococcus aureus and Escherichia coli was also examined, but in a synthetic washwater matrix under various combinations of temperature (6 to 32 degrees C) and pH (9.5 to 10.5) to determine whether there was likely to be a different response to variations in transport treatment among gram-positive and -negative bacteria. S. aureus was much more resistant to the lethal effects of high pH and moderate temperature than E. coli. These results indicated that samples of high pH should be held (transported) at less than or equal to 13 degrees C to optimize bacterial survival. Considering cost, ease of manipulation, and the ability to protect both coliforms and the bacterial population as a whole, the method of choice for transport of industrial samples was the direct addition of washwater to containers in which powdered KH2PO4 and Na2S2O3 had been placed to yield final concentrations, when dissolved, of 0.2 and 0.05% (wt/vol), respectively.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brodsky M. H., Ciebin B. W., Schiemann D. A. Simple bacterial preservation medium and its application to proficiency testing in water bacteriology. Appl Environ Microbiol. 1978 Mar;35(3):487–491. doi: 10.1128/aem.35.3.487-491.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Holley R. A., Proulx M. Use of egg washwater pH to prevent survival of Salmonella at moderate temperatures. Poult Sci. 1986 May;65(5):922–928. doi: 10.3382/ps.0650922. [DOI] [PubMed] [Google Scholar]
- Kotula A. W., Pierson M. D., Emswiler B. S., Guilfoyle J. R. Effect of sample transport systems on survival of bacteria in ground beef. Appl Environ Microbiol. 1979 Nov;38(5):789–794. doi: 10.1128/aem.38.5.789-794.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]