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students investigating mould and bacterial growth on food items

Submitted by sat on 11 March 2015

Guidelines for investigating microorganisms in schools: There are many considerations regarding the use of microorganisms in school laboratories. Science ASSIST is currently consulting authorities in order to make nationally consistent sensible and workable recommendations for best practice in school microbiology.   The activity you are describing has a low level of risk, provided safe operating procedures are followed, principally for containment of mould spores.

The Australian and New Zealand Standard AS/NZS 2243.3:2010 sets out requirements, responsibilities and general guidelines relating to safe handling and containment of microorganisms in laboratories.

Most school laboratories are classified as Physical Containment Level 1 (PC1), if they conform to the requirements set out in Section 5 of Australian and New Zealand Standard AS/NZS 2243.3:2010 Safety in Laboratories. This means they are suitable for work with microorganisms where the hazard levels are low and require no special containment equipment, and is suitable for work with microorganisms from Risk Group1i. Work at this level might, for example, include investigations with brewer’s or baker’s yeast and certain algae, protozoa or moulds.

The basic approach to working with microorganisms is to regard them all as potential pathogens i. It is the strict observance of correct procedures which enables students and staff to work safely with microorganisms. Aseptic technique is a fundamental skill in microbiology to maintain pure cultures whilst subculturing, to prevent microbes from being accidently released into the environment and infecting others in the laboratory.

Safe work practices: Behavioural management processes in science laboratories and practical work areas should ensure that staff and students are aware of any potential hazards for the particular activity to be undertaken.

Making sure safety issues are addressed and adjustments are made to meet the learning needs and maturity of students with adequate precautions in place will minimise any hazards.

It is important to conduct a site-specific risk assessment prior to the activity. Science Assist has developed a one-page risk assessment template that may be useful. See Risk Assessment Template.

Potential hazards: The release of Aerosols is the main hazard to consider during this activity. Aerosols are fine suspended particles of liquid containing microbial cells or spores, which can easily contaminate the laboratory. They are carried by air currents and increase the risk of infection by inhalation. Aerosols can be generated by spills.

Although the risks are very low for this activity, individuals who suffer from asthma, allergies or are immunosuppressed, may be more sensitive to exposure to spores and aerosols.

 Here is a link to a fact sheet on moulds and health concerns:

What safety measures and PPE have to be followed for this activity?

Is double bagging of food items enough?

Are students allowed to drop bread on various surfaces, then bag the slice of bread and see what grows on it?

How long should the bread be allowed to spoil in the bag at room temperature?

How to dispose of the contaminated food in the bags?

Clean up procedure

Information for growing mould on bread and other foods can be found in the links below:


i  Australian Standards AS NZS 2243.3-2010. Safety in Laboratories. Microbiology safety and containment