Describe a variety of infectious diseases caused by pathogens, including microorganisms, macroorganisms and non-cellular pathogens, and collect primary and secondary-sourced data and information relating to disease transmission, including: (ACSBL097, ACSBL098, ACSBL116, ACSBL117)
- design and conduct a practical investigation relating to the microbial testing of water or food samples
Practical investigation relating to the microbial testing of water or food samples
- food samples (bread, yoghurt, cheese)
- Agar plates
- Inoculating loops
- Bunsen burner
- Test tubes
- Marking pen
- Sticky tape
- Wipe all surfaces down with alcohol.
- Sterilise your test tubes.
- In separate test tubes mash small amounts of each food with 2mL distilled water.
- Sterilise your inoculating loop by passing it through a flame.
- Dip the inoculating loop into your food type and wipe it gently over the surface of an agar plate.
- Sterilise the loop again and repeat the procedure twice so that three agar plates are prepared for each treatment.
- Set aside 3 agar plates to act as controls.
- Close and seal each agar plate with sticky tape, then label it with a marking pen.
- Examine the plates after 15 days and count the number of fungi colonies and the number of bacterial colonies.
- Be careful when using the Bunsen burner and hot inoculating loop.
- Only open the agar plate a little bit, to avoid mouth bacteria entering the plate.
- Wear gloves to avoid transmission of bacteria.
- Once the agar plate is sealed off, do not open it again.
- Wash hands thoroughly before leaving the laboratory.
Extract from HSC Biology Stage 6 Syllabus. © 2017 Board of Studies NSW.