November 9, 2013 · 3:00 PM
Scientists have figured out way to identify microbes by growing them on so-called "chromogenic media", that make them turn different colors on a Petri dish.
We'd love to make a completely food-safe version of this, so we can do Microbiology 101 demos with kids. The idea is to bring in a wide variety of colored foods, use each to color some gelatin or agar gel in a Petri dish, streak a mixture of (friendly) microbes on them, and check for any color changes.
For example, plant pigments such as cabbage juice or turmeric that change color based on acidity would allow you to distinguish between yeast and bacteria that produce acid, versus those that don't. Other plant colors may be degraded by certain bacteria, or concentrated by others. We'll have some colored plants and food dyes to experiment with, but please bring some of your own to experiment with. Got some weird oil-based food dyes? Some spice or edible flower you think we may not have thought of? Bring it!
You'll be part of an international DIYbio experiment, get to play with lots of pretty colors, and learn some basic microbiology techniques along the way!