Explain the Inoculating Loops and Needles?

These are most commonly used tools for inoculation. The inoculating loop consists of insulating handle at the end of which inoculating wire is present. Inoculating wire is about 3 inches long and made of nichrome or platinum. It is a straight wire in case of inoculating needle but in inoculating loop end of the wire is bent round to form loop.

Figure illustrates the inoculating needle and loop. During inoculation, inoculating wire is sterilized by heating in blue (hottest) portion of the flame till it becomes red hot followed by cooling either by touching to petri dish cover or inner surface of culture tube to avoid killing of microbial cells. Only a small amount of culture is used for inoculation. This can be accomplished by touching a single colony on agar surface by inoculating needle or by taking a loopful of culture from broth medium. After inoculation, inoculating wire is again sterilized to destroy remaining microorganisms.