In this video, we're going to begin our lesson on dry heat as a physical method for controlling microbial growth. Dry heat is simply heat that has no moisture or liquid content, which is why it's called dry heat. Incineration is a type of dry heat that refers to the destruction by burning with a direct flame. This process turns the cell components into ashes.
Hot air ovens are another way to deliver dry heat. As their name implies, these ovens kill microbes with dry heat by destroying cell components and denaturing or inactivating proteins. Dry heat generally requires a higher temperature and more time to kill microbes than moist heat does.
We'll delve more into moist heat in our next lesson video. Moist heat can kill microbes faster and at lower temperatures than dry heat. However, an advantage of using dry heat over moist heat is that dry heat can be used on moisture-sensitive items that do not work well with moisture. For example, powders and oils, which cannot be used with moist heat because it can change their composition and are not compatible. However, dry heat can be used on them.
If we look at our image below, notice on the left-hand side we're showing you a laboratory tool being burnt with a direct flame. This is a form of incineration of a laboratory tool to help control the microbial growth on this tool. On the right, we're showing you a hot air oven. This hot air oven kills microbes on laboratory instruments. Laboratory instruments that are not sensitive to heat can be placed inside this hot air oven, and the microbial growth can be controlled with these hot air ovens.
This concludes our brief lesson on dry heat as a physical method for controlling microbial growth. We'll be able to get some practice and learn more about other physical methods of controlling microbial growth as we move forward in our course. So, I'll see you all in our next video.
