We cannot argue that micro-organisms are as important to our lives as photosynthesis. We shouldn't describe bacteria simply as harmful or beneficial, because our relationship with micro-organisms is complex, our lives and those of the bacteria we host are deeply intertwined. There are perhaps more non-human prokaryote cells in a human body than there are human cells.

However there are some essential measures which have to be taken when working in the lab with microorganisms.  A teachers we have a duty to protect our students from the risk of danger.

• Use the safest practicable methods, with the facilities you have.  Sterile technique if possible.
• Write a risk assessment
• Include preparation, experimental techniques, cleanup and disposal as well as emergency procedures for spills and first aid.
• All microorganisms should be treated as potential pathogens, samples known to be harmless may become contaminated.
• The number of cultures should be kept to a minimum
• Incubation Temperature should not be above 30°C  to reduce the probability of culturing pathogens adapted to human body temperature.
• Anaerobic conditions should be avoided è don't tape around the petri dish.
• Bacteria cultured from the environment should not be opened following inoculation and they should never be sub-cultured.
• Enforce strict lab rules about eating, drinking, other hand to mouth movements.
• Students with broken skin protected by plasters, gloves etc.
• Lab coats should be worn and not removed from the lab
• Desks should be cleaned afterwards with a suitable sterizing solutions.
• Hands should be washed at the end of the lesson with soap and water.

http://file.southernbiological.com/Assets/Products/Specimens/Microbiological_Specimens/MicrobiologySafetyConsiderations.pdf

http://www.nuffieldfoundation.org/practical-biology/incubating-and-viewing-plates

www.microbiologyonline.org.uk/sgmprac.htm
Society for General Microbiology – source of Basic Practical Microbiology, an excellent manual of laboratory techniques and Practical Microbiology for Secondary Schools, a selection of tried and tested practicals using microorganisms.

www.microbiologyonline.org.uk
MiSAC (Microbiology in Schools Advisory Committee) is supported by the Society for General Microbiology (see above) and their websites include more safety information and a link to ask for advice by email.