In California, we take it for granted that beans, lentils and nuts in the bulk aisle of the grocery store are dried properly to avoid being exposed to toxins from mold.
That's thanks to food safety technology and consumer safeguards that are largely absent in developing nations, according to Beth Mitcham, Director of the UC Davis Horticulture Innovation Lab, which works on improving people's livelihoods and nutritional health through horticulture.
"To store something safely it has to be dried to a low enough moisture content to prevent the growth of fungi," says Mitcham.
One of the major challenges to the health and nutrition status of people in developing countries is exposure to fungi (specifically mycotoxins) in foods that haven't been dried properly, according to the Food And Agriculture Organization of the United Nations. Livestock are also vulnerable to fungal toxins in animal feed.
That's where DryCard comes in.
It's a small paper card with a Cobalt Chloride strip on the back.
"The paper changes color as the relative humidity changes," explains Mitcham.
The DryCard invention was developed by Mitcham's colleagues, UC Davis scientists Michael Reed and Jim Thompson, while they were working on a research project on better strategies for drying vegetable seeds.
"It's a very inexpensive tool that can allow the farmer to know if the product has been dried sufficiently so that it can be safely stored," says Mitcham.
You slip the card into a bag of grains and 20 minutes later, a color-coded moisture reading appears.
Small-holder farmers can use DryCard to assess whether their grain, beans and produce (often dried in the sun) are sufficiently dry to sell at market.
Mitcham says consumers could use it to see if goods they are buying are dry enough to be safely stored and consumed.
The DryCard prototype costs 25 to 50 cents.
Researchers at the UC Davis Horticulture Innovation Lab want to keep the cost low. They are looking to team up with donors who can help developing countries start producing and distributing DryCard locally, starting in Bangladesh and Guinea.