prior to staining bacteria for viewing under the microscope a bacterial smear must be made to make a microscope stain of bacteria the bacteria must be placed on the slide in a thin smear smears are prepared differently for solid and liquid cultures begin by cleaning each slide put some cleanser on your finger and then spread the cleanser across the slides rinse the slides with to remove the cleanser and blot the slides dry label each slide with the type of microbe you will be transferring and make a dime-sized circle on the underside of both slides we will start with the liquid culture flame your loop by holding it in the hottest part of the flame notice where the wire is red-hot this is the hottest part of the flame to sterilize the loop hold the loop so the entire wire gets red hot allow the loop to cool so the bacteria are not overheated and distorted and so you don't create an aerosol spreading bacteria in the air cooling takes about 30 seconds remember you can't touch the loop or set it down if you need to set the loop down use a rack or stand so that the loop doesn't touch the counter obtain the liquid culture and gently flick the tube to suspend the bacteria notice the sediment in the tube moving into suspension hold the tube at an angle hold the loop like a pencil remove the cap with your ring and pinky finger of the hand holding the loop past the mouth of the tube through the flame quickly the hot air will keep airborne contaminants out of the tube use your loop to pick a loop full of broth flame the tube and replace the cap pick up one of the slides and spread the loop full of bacteria in the circle you don't have to stay within the lines repeat this procedure to place two or three loop folds of culture on the slide flame the loop and let it cool using your ring and pinky finger remove the cap of the tube quickly pass the tube through the flame obtain a loop full of broth pass the tube back through the flame and recap the tube spread the loop full of broth on the slide let the smear air dry do not blow on the slide or heat the slide now we will make a smear using the solid culture when pulling a sample from a plate or a slant very little sample is needed if you pull too much you may make a smear that is too thick flame the loop and put a loop full of water in the circle on the other slide flame the loop and let it cool with the cooled loop gently scrape some bacteria off the surface of the agar remove the cap from the tube pass the tube through the flame and then use the loop to scrape the surface of the agar pass the tube through the flame and recap the tube add the loopful of agar to the water on the slide spread to make a milky looking emulsion flame your loop before setting it down let both smears air dry do not blow on or heat the slides when the smears are completely dry they can be fixed so the cells adhere to the slide fixing denatures enzymes preventing them from digesting the cell fixing also preserves the size and shape of the cell during staining a smear can be heat fixed by passing it quickly through a flame two or three times alternately chemical fixing can be done with methanol cover the smear with methanol for one minute let the alcohol run off and let the slide air dry remember to fix a smear after it has air dried completely and use either heat fixing or chemical fixing