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Pouring Plates from Prepared
Bottled Media
Primary Hazard Considerations
Never purchase living specimens without having a disposition strategy in place.
When pouring bottles, agar is HOT! Burning can occur. Always handle hot agar bottles with heat-protective gloves.
For added protection wear latex or nitrile gloves when working with bacteria, and always wash hands before and after
with hot water and soap.
Availability
Agar is available for purchase year round.
Information
• Storage: Bottled agar can be stored at room temperature for about six months unless otherwise specified.
Never put agar in the freezer. It will cause the agar to breakdown and become unusable. To prevent contamination
keep all bottles and Petri dishes sealed until ready to use.
Pouring Plates
Materials Needed:
• Draft-free enclosure or Laminar flow hood
• 70% isopropyl alcohol
• Petri dishes
• Microwave or hot water bath or autoclave
1. Melt the agar using one of the following methods:
a) Autoclave: Loosen the cap on the agar bottle and autoclave the bottle at 15 PSI for five minutes. While wearing
heat-protective gloves, carefully remove the hot bottle and let it cool to between 75 – 55°C before pouring. This
takes approximately 15 minutes.
b) Water Bath: Loosen the cap on the agar bottle and place it into a water bath. Water temperature should remain at
around 100°C. Leave it in the water bath until the agar is completely melted. While wearing heat-protective gloves,
carefully remove the hot bottle and let it cool to between 75 – 55°C before pouring.
c) Microwave: Loosen the cap on the agar bottle before microwaving. Heat in one minute intervals on low power
until all of the agar is melted. Between intervals, gently swirl the bottle to make sure the agar is melting evenly.
While wearing heat-protective gloves, carefully remove the hot bottle and let it cool to between 75 – 55°C
before pouring.
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