When preparing a bacterial smear the slide is airdried first

When preparing a bacterial smear, the slide is air-dried first, and then heat-fixed. Why is it necessary to air-dry first? After all, heating would evaporate the water, and do it quicker than the slide warmer.

Solution

D. To fix the bacteria to the slide; so that they don’t wash off.

During the staining experiment, we should make a smear on the glass slide, smear could be small one to size of a coin. Before we can heat fix the smear we should allow the smear to be air dry, since if we don’t do that there may be chance of bacteria to be forced into air, by which can cause infections.