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The rate of total microbial death on four bronzes varied from within 50–270 minutes at 20 °C, and from 180 to 270 minutes at 4 °C. The kill rate of E. coli O157 on copper-nickel alloys increased with increasing copper content. Zero bacterial counts at room temperature were achieved after 105–360 minutes for five of the six alloys.
The laboratory procedure involves making serial dilutions of the sample (1:10, 1:100, 1:1000, etc.) in sterile water and cultivating these on nutrient agar in a dish that is sealed and incubated. Typical media include plate count agar for a general count or MacConkey agar to count Gram-negative bacteria such as E. coli. Typically one set of ...
Run-and-tumble motion is a movement pattern exhibited by certain bacteria and other microscopic agents. It consists of an alternating sequence of "runs" and "tumbles": during a run, the agent propels itself in a fixed (or slowly varying) direction, and during a tumble, it remains stationary while it reorients itself in preparation for the next run.
The curve for E. coli is given in the figure, with the most effective UV light having a wavelength of 265 nm. This applies to most bacteria and does not change significantly for other microbes. Dosages for a 90% kill rate of most bacteria and viruses range between 2,000 and 8,000 μJ/cm 2.
Even objects with a solid silver surface (e.g., table silver, silver coins, or silver foil) have a bactericidal effect. Silver drinking vessels were carried by military commanders on expeditions for protection against disease. It was once common to place silver foil or even silver coins on wounds for the same reason. [23]
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The 2013 revised total coliform rule and the 1989 total coliform rule are the only microbial drinking water regulations that apply to all public water systems. The revised rule highlights the frequency and timing of microbial testing by water systems based on population served, system type, and source water type.
The autoclave process gives a very high pathogen and virus kill rate, although the fibrous products which come from the process are susceptible to bacteria and fungus as they are high in starch, cellulose and amino acids. When designed for sterilizing waste containing mostly liquids, a waste autoclave is known as an Effluent Decontamination System.