Fly food for vials and bottles

Fly food for vials and bottles. (Recipe from the Abmayr lab)
{Modified 6/16/07 according to Graham Thomas' protocol. Addition of propionic acid serves as a bacteriacide to inhibit formation of the shiny slime that sometimes forms on the food. The slight reduction in Agar might keep the food from pulling away from the sides of bottles. Monitoring the temperature with a thermometer might help prevent the food from being over cooked and assure that the food is not too hot when the Tegosept and propionic acid are added.}

Things to do in the lab (underlined items are notable changes from the Thomas lab):

In a large plastic container, which has a lid, combine the following ingredients:

1100 g Table sugar (sucrose from the grocery store, not reagent grade, stored in the fly room)
274 g Saf or Fleishmen's baking yeast (stored in fly room)
520 g Cornmeal (stored in the fly room)
70 g Agar (Sigma A-7002, USB 10654, usually stored under the balance, do not use Bactoagar or agarose)

Snap the lid in place and thoroughly mix the dry ingredients by inverting the container many times.

Prepare a solution of Tegosept in a flask (also called Lexgard):

92 ml of 95% Ethanol (usually stored near the hood)
23.8 g of Tegosept (usually stored in a small container under the balance or in a large white canister near the doorway to 450 N. Frear)

Measure out 15 ml of propionic acid (this could be the most important modification since it should inhibit bacterial growth)

In addition to the dry ingredients, the Tegosept solution, and the propionic acid, transport the following items on a cart to the fly kitchen: rayon or cotton balls (rayon is preferred but are no longer available through VWR), vials and bottles, Bottle caps, tubing to use with Monostat pump.

Things to do in the kitchen (172 N. Frear):

Rinse the kettle with water and let the water drain through the bottom. Close the valve.

Put 8.5 liters of water in the steam kettle.

Turn on the stirrer. Open the steam valve and, with a autoclave glove for protection, open the valve to purge condensate from the steam line. There will be a loud noise as the condensate is purged. Once steam is emitted, the purging valve can be released.

Turn on the stirrer at a setting sufficiently high to get good mixing without splattering the food (setting between 2 and 3). Bring the water to a boil.

Shut off the steam and slowly add dry ingredients. Avoid having the ingredients form into lumps.

Mix for several minutes until the food is uniform. Shut-off the stirrer and measure the depth of the food with the yard stick. Remember this depth as water will be added later to compensate for evaporation.

Start the stirrer and continue to cook the food for 1 minutes. Turn steam on and off intermittently to keep the solution around 92 degress C.

After 15 minutes of cooking, stop the stirrer and measure the depth. Add water to return the depth to its original level.

Start the stirrer again and adjust the food to 80 degrees centigrade either by heating or allowing it to cool. Then add the tegosept/ethanol solution and the propionic acid {it is important not to add these ingredients when the temperature is above 80 degress because they evaporate}.

Mix for 5 minutes.

Turn off the stirrer. Pump the food into vials and bottles. Turn on the steam and mix as necessary to keep the solution from becoming too thick to dispense.

The following settings on the Monostat pump could be appropriate (these may need to be altered):

Dwell Dispense Flow

Vials 2 1 2

Plastic Bottles 2 2.5 3

****Thoroughly clean the kitchen and lab when finished****

Cap the vial with Rayon (or cotton) balls and the bottles with cardboard caps.

Store in bins in the cold room.