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Why did the petri dishes have to be put in a dark location for several days?
Place the Petri dishes in a warm, dark place. Leave the Petri dishes in a warm, dark place where the bacteria can develop, undisturbed, for several days. Remember to store the dishes upside down, so the bacterial growth remains undisturbed by any water droplets.
Why are culture plates placed in the dark?
It does not prevent contamination, but slows its growth. Consequently contamination may go undetected until the cultures are incubated. It is much better to store media at room temperature and detect contamination before the medium is used.
Where should the petri dishes be disposed of?
Dispose of unused plain agar in plastic plates directly into a trash can. Agar with any additives are biohazards and should be sterilized before disposal. Scrape unused agar out of glass petri dishes and throw it away.
Why does bacteria grow better in warm temperatures?
Bacteria, single celled eukaryotes and other microbes, can only live and reproduce within a certain range of environmental conditions. As the temperature increases, molecules move faster, enzymes speed up metabolism and cells rapidly increase in size.
What temperature does bacteria grow?
Some bacteria thrive in extreme heat or cold, while others can survive under highly acidic or extremely salty conditions. Most bacteria that cause disease grow fastest in the temperature range between 41 and 135 degrees F, which is known as THE DANGER ZONE.
Can I grow bacteria without agar?
Plain agar won’t work because it contains no ‘food’ for the bacteria. You have to buy NUTRIENT agar because that has sugars, salts, nitrogen source, etc that bacteria need to grow.
Why are agar plates incubated upside down?
Petri dishes need to be incubated upside-down to lessen contamination risks from airborne particles landing on them and to prevent the accumulation of water condensation that could disturb or compromise a culture.
How can a streak plate become contaminated?
How can a streak plate become contaminated? If the loop is not sterilized. If you drop the plate.
Can you pour agar down the sink?
Do not pour melted agar down the sink drain! Some agar media may have boiled over during autoclaving and will solidify in the pipes, clogging the sink drain, once cooled.
Can you autoclave plastic petri dishes?
When paired with the correct autoclaving accessories, the autoclave sterilization method for plastic agar plates/Petri dishes can be both effective in deactivating harmful microorganisms and preventing a large mess.
Why does bacteria grow better in the dark?
In the light, both strains of bacteria take in more organic carbon, including sugars, metabolize them faster. In the dark, those functions are reduced, and the bacteria increase protein production and repair, making and fixing the machinery needed to grow and divide.
What temp kills bacteria?
The only way to kill bacteria by temperature is by cooking food at temperatures of 165 degrees or more. Bacteria also die in highly acidic environments like pickle juice.