Items that do not come into direct contact with microorganisms do not need to be sterilized, but they need to be disinfected. You will use disposable, plastic, inoculating tools (loops and transfer pipettes) sterilized by the manufacturer, typically using radiation. The media provided in the lab kit has been sterilized. Media is typically sterilized by autoclaving which uses temperature and pressure to kill microorganisms. The media must be sterile (free of all forms of microorganisms). Today, most media are available commercially in powdered form and only need to be rehydrated with water. Tryptic soy and nutrient agar support the growth of a wide range of microorganisms. In this lab exercise, you will be using two different complex media, tryptic soy (broth and agar slant) and nutrient agar (plate). Melted agar is poured into a Petri plate for a plate. M elted agar is poured into a test tube and then allowed to solidify at a n angle for an agar slant.

A solid medium may come in a tube (agar slant), or in Petri dish (agar plate).

Media can be in liquid form, known as broth or a solid form called agar, referring to the solidifying ingredient. The potato served as a growth medium for the bacteria. He prepared slices of boiled potatoes and smeared them with samples from diseased animals. Robert Koch was a German physician who pioneered many microbiological techniques that are still used today. Early microbiologists prepared their own media using available materials at the time, such as beef extract and vegetable slices. Nutrient material suitable for the cultivation of microorganisms is called media. Paste these photos into the Aseptic Technique Questions Document introduction Take a photo with your photo ID during the lab exercises when you see this icon

Two types of aseptic technique