Why autoclave plates

On solid media, a single microbe will grow and divide to produce a "colony," a spot of identical descendants. Different types of microbes produce colonies with different characteristics-shape, color, texture-which help microbiologists determine if a culture is pure, or identify the types of microbes in a mixed sample.

A number of biological supply companies sell pre-made plates, but making your own is much less expensive. With a little practice, you will find that it is very easy to make your own plates, and you will have the added flexibility of being able to customize recipes to suit your needs. Choose a recipe from the Media Recipes page or use one of your own. Decide how many plates you will need. Our recipes will make 1 L mL of media, enough to fill approximately forty mm plates, but they can be scaled up or down as needed.

Plan on using about 25 mL per mm plate. Use a glass container ideally an Erlenmeyer flask that will hold at least twice the volume of your media. Make sure the agar dissolves completely.

The media may look cloudy, or you may see small, translucent lens-like objects floating in it. Continue boiling until the media is completely clear; this may take longer than 15 minutes. Incompletely dissolved agar will leave your media squishy or fragile. Some supplies for preparing plates with media. Procedure Preparing the media Label a clean glass autoclavable mL autoclavable bottle with media name, date, and initial. Note: only fill bottle halfway, to avoid overflow during the heating process in the autoclave.

For a mL bottle, calculate the needed weight of powdered media to make mL. Subtract that from to determine the volume of water to add. Stir or shake until fully mixed and check that there are no lumps. Add a piece of autoclave tape to the cap or bottle and loosen the cap a half-turn. If using a container with no cap, then cover loosely with aluminum foil.

Setting up the autoclave Place the prepared media bottles into a metal tray. Add distilled water until it covers the bottom of the tray; about cm deep. Place into the autoclave. Autoclave at o C for 15 minutes at 15 psi. Once the cycle is complete, wear heat-resistant gloves to remove the tray and bottles from the machine. Allow bottles to cool to approximately 60 o C. Prepping the workspace: To keep as sterile of an environment as possible to avoid contaminating the media and plates, don a lab coat and gloves, and use a disinfecting agent or wipes to wipe down all surfaces.

This includes tabletops and edges, gloves, scissors, permanent markers, etc. Make sure to clean your gloves if they have touched another surface that is not disinfected eg. If available, use Bunsen burners and carefully pour near the open flame to better prevent airborne contaminants.

Once the area is disinfected, bring out the sterile Petri dishes. Keep the sterile dishes closed. DoaneX Open Learning Academy. Graduate Education. Doane at a Glance. Crete Grand Island Lincoln Omaha. Schedule a Visit. Visit Apply. Agar and Plate Preparation. Schedule a Visit Apply Today. If the chemical indicators fail on two consecutive loads, notify your Department Safety Manager. Biological indicator vials contain spores from B.

Autoclaves used to treat biological waste will be evaluated with a biological indicator by EHS on a quarterly basis. Autoclave Use Autoclaves provide a physical method for disinfection and sterilization. They work with a combination of steam, pressure and time. Autoclaves operate at high temperature and pressure in order to kill microorganisms and spores. They are used to decontaminate certain biological waste and sterilize media, instruments and lab ware.

Regulated medical waste that might contain bacteria, viruses and other biological material are recommended to be inactivated by autoclaving before disposal. Increased cycle time may be necessary depending upon the make-up and volume of the load. The rate of exhaust will depend upon the nature of the load. Dry material can be treated in a fast exhaust cycle, while liquids and biological waste require slow exhaust to prevent boiling over of super-heated liquids.

Plastic Polypropylene is an inexpensive resin that can resist autoclave temperatures. Polypropylene containers are often used as secondary containers to hold materials that are autoclaved. Polycarbonate can also withstand high temperatures. Gloves Gloves must be placed inside of an autoclavable biohazard bag and exposed to a steam setting; gloves will melt slightly but will not burn when autoclaved in this manner. Stainless steel Most metals are designed for extreme conditions and are intended to be sterilized.

Make sure to remove any plastics, liners and other items that may melt or combust.