Microbial Quality of Cool Water Washed Shell 
 Eggs

The current project was conducted to determine the microbial quality of commercially processed shell eggs during extended storage. Unwashed eggs were collected at the accumulator before entering the processing line. Washed eggs were retrieved after placement in flats. All eggs were stored on pulp flats at 4°C for 10 weeks. Twelve eggs from each treatment were rinsed on the day of collection and during each week of storage. After rinsing, eggs were sanitized in ethanol, and contents were aseptically collected. Total aerobes, yeasts and molds, Enterobacteriaceae, and pseudomonads were enumerated from shell rinses and pooled egg contents. During storage, no differences were found between unwashed and washed eggs for Enterobacteriaceae and pseudomonads in either shell rinses or contents. No differences were found between treatments for population levels of total aerobes or yeasts and molds in the egg contents throughout the storage period. Significant differences between treatments were found at each week of storage for external shell contamination by total aerobes. The highest unwashed egg contamination occurred at week 8 of storage and the lowest was at weeks 0 and 1 of storage. The highest shell contamination with aerobic bacteria on the washed eggs was found at week 0 of storage and the lowest was at week 7. Yeast and mold contamination determined by shell rinses was also significantly different between treatments at each week of storage. Commercially washed eggs were significantly less contaminated than were unwashed eggs for the populations monitored.

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Microbial Quality of Human Wastes and Treatment Plant Effluent

Water Science & Technology ◽

10.2166/wst.1986.0297 ◽

1986 ◽

Vol 18 (7-8) ◽

pp. 257-265 ◽

Cited By ~ 3

Author(s):

K. Kawamura ◽

M. Kaneko

Keyword(s):

Staphylococcus Aureus ◽

Vibrio Cholerae ◽

Treatment Plant ◽

Microbial Quality ◽

Chlorination Process ◽

Fecal Streptococci ◽

Human Wastes ◽

Micro Organisms ◽

Spore Forming Bacteria

In order to evaluate the microbial quality of human wastes and effluents from treatment processes, the microbial flora of samples was examined. Total coliforms, fecal coliforms and fecal streptococci were used as indicator micro-organisms, and Vibrio cholerae non O-1, Salmonella, Staphylococcus aureus and Welchii (Clostridium perfrigens) were selected as pathogenic organisms. Salmonella was detected in only the water samples from the night soil treatment plant, while Staphylococcus aureus was detected in the night soil and the samples from the night soil purification tanks. Vibrio cholerae non 0-1 was not detected in any samples, but Welchii existed in almost all samples. Generally, the density levels and distribution patterns of the indicator micro-organisms were similar to those in the raw wastewaters. The microbial flora was not changed remarkably after the primary sedimentation process and the biological treatment process. After the chlorination process, total colonies, spore-forming bacteria, Welchii, moulds and fecal streptococci could survive, and spore-forming bacteria formed the majority of the total colonies in the well-chlorinated effluents. Welchii at the level of 103/100 ml can be used as the indicator micro-organism to ensure a sanitary safe discharge, because it can survive at the level of 103−104/100 ml even if other indicators and pathogenic micro-organisms are inactivated completely by the chlorination process.

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