Science Buddies: "Ask an Expert"

I am doing an experiment on which energy drink molds quicker.
Red Bull is an example and I can only use two types of drinks.
I started the experiment on 3/10/2006 and it is due on 3/21/2006.
This was too late I am afraid.

My mom knows they mold but could not remember how long
it took to mold.

Both energy drinks have sugar. Will they mold? If so, how
long will it take? Does the sugar in the energy drink prevent
it from molding?

If a sugar-free drink is used and I think that is the one my
mom noticed that molded - how long might it take?

Is there any way to speed up the molding process?

Is it possible to get results before 3/21/2006?

Help!

Thank you!

Kyle Collett

Mold can grow just about anywhere, but it might be a long shot to try to grow visible colonies on an energy drink in 11 days. When the concentration of sugar is very high, it is actually a preservative:
See table 3 in:
http://textbookofbacteriology.net/control.html

For quicker results, you could try to modify this experiment by subsituting energy drinks for the water, sugar water, and lemon juice.
http://www.microbe.org/experiment/nightmares.asp

Hi!

Thank you for your prompt reply and great information!

I sure know why the sugar energy drinks are not molding.

What about sugar free energy drinks. My mom knows
they do mold.

How long would the molding process be for the sugar free
ones?

Would there be a way to speed that process up?

Thank you again!

p.s. I may have sent this reply already - sorry for the inconvenience

Kyle Collett

I would guess it will take a very long time to grow on a sugar free drink, unless there are some other organic additives. How many calories in the drink? If it is zero, then there is no source of energy for the mold to grow.

Thanks again for your help!

Red Bull Sugarfree has 10 calories.

Ingredients:

Sodium 200 mg
Total carb 3 g
Niacin 100%
Vitamin B 12 80%
Vitamin B6 250%
Pantothenic Acid 50%

Carbonated water, sodium citrate, taurine, glucuronolactone,
caffeine, acesulfame K , aspartame, inositol, xanthan gum,
niacinamide, calcium pantothemate, pyrodoxine HCL, vitamin
B12, phenylalamine.

What do you think? Are any of these organic additives?

Thanks!

Kyle Collett

That contains some carbohydrates which could support growth, but it also has sodium citrate which can serve as a food preservative to prevent microbial growth.
http://www.answers.com/topic/sodium-citrate

If you need quick results, I'd suggest continuing your current experiment, just in case it works out, and also considering another approach such as the modified bread mold experiment.

Kyle,

I recommending posting on the Life Science section of the Science Buddies Expert Forum. You will be reaching biologiest who may be able to help you better.