GROWING BACTERIA

GROWING BACTERIA The action of antibiotics and disinfectants can be

investigated using cultures of microorganisms (populations of microorganisms that have been grown for a purpose). It is important that the cultures are uncontaminated by other microorganisms, so sterile conditions are needed:

the Petri dishes, nutrient agar jelly and other culture media must be sterilised

the inoculating loops used to transfer microorganisms must be sterilised (usually by passing the metal loop through a Bunsen burner flame)

the lid of the Petri dish is sealed with sticky tape to stop microorganisms from the air getting in and contaminating the culture.

TESTING DISINFECTANTS

You may grow bacteria to test disinfectants. First you’d need to sterilise all the equipment you’ll be using like inoculating loop etc. Only open the Petri dish a bit when you put the disinfectants in because you don't want to let in unwanted micro organisms into the Petri dish as this will contaminate. So you would place a disinfectant into an area of the Petri dish. Then you leave it for a while. Then if you look at the Petri dish again you will be able to see the area of bacteria that disinfectant has killed

SAFETY

Bacteria reproduce and grow quicker. If you grew the pathogens at body temperature (37c). The maximum temperature used in school is about 25c because if you grow them at body temperature then the bacteria you grow might be harmful to health but in laboratories they may grow bacteria at body temperature depending on what they wanted the bacteria for.

http://www.youtube.com/watch?v=LSZE6WofLAs

Special thanks to my friend Leon Chan. Without

whom this video would not be available on this PowerPoint