Use of a Microincinerator in Microbiology Lab - P2
Microincinerator with slide tray for heat fixing bacterial smears.
Sterilizing an Inoculation Wand: To sterilize a loop, place it in the hub (opening) of the microincinerator for just a few seconds, until the portion of the inoculation wand that is being sterilized glows red. Once the loop is removed from the incinerator, it almost instantly stops glowing, and within 20 seconds or so, will be cool enough to use.
Heat Fixing Bacterial Smears: A bacterial specimen on a microscope slide is called a smear. It is prepared using a bacterial sample obtained with an inoculation loop that is then mixed with water or physiological saline in the surface of a microscope slide.
Page last updated: 2/2016
Sources & Resources
- Schauer Cynthia (2007) Lab Manual to Microbiology for the Health Sciences, Kalamazoo Valley Community College.
- Bauman, R. (2005) Microbiology. Pearson Benjamin Cummings.
So that the smear doesn’t wash away during staining, it is heat-fixed, using either the open flame of a Bunsen burner or, preferably, a slide platform affixed to the top of a microincinerator (see photo to right).
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Bacteria are very small and essentially colorless, so the bacterial smear must eventually be stained in order to be visible when viewed through a microscope.
By placing the bacterial smear slide on the hot slide platform for several minutes, the bacteria are killed and the smear is affixed to the slide so that it will not wash off during staining.
G+ & G- control smears on outside. Unknown bacteria in center.