The small size of microbes and the consequent need to deal with cultures that contain many millions of microbial cells require special procedures for their safe use.
Activities involving microbes are controlled by the Control of Substances Hazardous to Health (COSHH) Regulations and teachers and technicians have a duty under the Health and Safety at Work Act to comply with any safety instructions given by their employers. These include using model risk assessments for which it is necessary to refer to appropriate publications such as CLEAPPS Laboratory Handbook (2006), section 15.2, Topics in Safety, 3rd edition (ASE 2001), Microbiology: an HMI Guide (DES, 1990) and Safety in Science Education (DfEE, 1996). The guidelines are straightforward and largely common sense and, as such, are not an obstacle to conducting interesting microbiological investigations in a school laboratory.
Planning ahead is essential when embarking on practical microbiology investigations. There are five areas for consideration:
- Preparation and sterilization of equipment and culture media
- Preparation of microbial cultures as stock culture for future investigations and inoculum for the current investigation
- Inoculation of the media with the prepared culture
- Incubation of cultures and sampling during growth
- Sterilization and safe disposal of all cultures and decontamination of all contaminated equipment