STERILE TECHNIQUE AND AGAR CULTURE

The air we breathe is a living sea of microscopic organisms that ebbs and flows with the slightest wind currents. Fungi, bacteria, viruses and plants use the atmosphere to carry their offspring to new environments. These microscopic particles can make sterile technique difficult unless proper precautions are taken, [f one can eliminate or reduce the movement of these organisms in the air, however, success in sterile technique is assured. 

There are five primary sources of contamination in mushroom culture work  

The immediate external environment The culture medium The culturing equipment The cultivator and his or her clothes The mushroom spores or the mycelium 

Mushrooms—and all living organisms—are in constant competition for available nutrients. In creating a sterile environment, the cultivator seeks to give advantage to the mushroom over the myriad legions of other competitors. Before culture work can begin, the first step is the construction of an inoculation chamber or sterile laboratory. 

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Sterile Technique media (agar and grain) preparation, spore germination, tissue culture and spawn-making. 

Suspended in the air is an invisible cloud of contaminants. These airborne spores are the primary source of contamination during agar and grain culture, and they are the major force defeating beginning cultivators. To control contamination, the cultivator must start with a sterile laboratory. Without pure culture spawn, the prospect for a good crop is slight, no matter how refined one s other techniques. 

The ability to transfer microorganisms from one container to another without contamination is crucial to success in the microbiology laboratory. These techniques serve as the basis for subsequent work such as starter culture preparation or maintaining viable cultures in long-term storage. Transfer loops are normally used to transfer to the surface of agar (Petri plates and slants), whereas transfer needles are used to prepare stab cultures. Both implements are sterilized by heating in an open flame until red hot (Fig. 13.1). 

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