Sorry, what a shame.

It's got to be the culture medium?

What kind of water are you using?

What temp are the cultures kept in ?

Is the mix home-made?

I use this /never had a problem Repashy "super fly".
Repashy Superfoods :: RETAIL SALES :: By Product Name :: SuperFly :: SuperFly 16 oz BAG (one pound) - Repashy Ventures - Distributor Center
Spare supply is kept in the frig.

Every home-made recipe I've tried has had some little issue I've decided to leave it up to the experts!
2 other brands I've tried had issues s well.
I got sick of wasting the $$ trying. Plus, the risk of being left without food for the frogs is really scary
I finally solved the hydei problem ( they take longer to culture) by simply adding MUCH more culture medium and make it more watery. I purchase my excelsior form Josh's Frogs...It's nice and thick/ the craft store stuff breaks down.
I store spare excelsior is stored in the freezer.

I heat my cultures on a seeding/ starter mats /turned on during the night/in these colder months.
purchased here: http://www.sunflowersupplies.com/pro...TION-SEED.html
they work like a charm!

The cinnamon is a great idea Gwen ! I can't imagine it causing a problem?
http://www.education.com/science-fai...old-inhibitor/

Here is a recipe ( i've never tried it ) It does however have methyl paraben added as well

Fruit Fly Culturing,
Making your own fruit fly cultures will save money and is easy to do. We recommend making a couple of cultures once a week for a pair of frogs.
This is the recipe we use.

1 cup of powdered sugar
4 teaspoons Methyl Paraben (to prevent mold)
8 cups potato flakes
1 cup fruit flavored baby cereal
1 cup brewers yeast
1 teaspoon cinnamon

Add 1/3 cup of mixture to a container and enough water to make it the consistency of apple sauce. Lightly sprinkle fresh baker's yeast on top, add excelsior or crumpled up coffee filters. Add some flies from a previous culture. Keep in a place that is not too dry and room temperature. Melanogaster's generally take 10-14 days to hatch out and hydei take a bit longer and don't yield as many flies.

above recipe found on : http://www.carolinadartfrogs.com/frog-care.html

Hang in there !!!
There's got to be a better way to culture FF ! Right !