Milk is an important food for people in many countries, but adulteration is all too common.  Suppliers of fraudulent milk might add water to increase the volume of their product, and then put in sugars, urea, or starch to restore the density, taste, and appearance of the milk.  In a recent publication, Notre Dame graduate student Jamie Luther describes how to catch these food frauds using a paper test card. The chemicals and enzymes needed to detect specific adulterants were stored in dry form on reaction areas of the test card. When drops of milk are added to the reaction areas, they dissolve the reagents and if the adulterant is present, a color change is caused. The user can compare the color to a standard sample or use an image analysis program to read the result from the card.   In laboratory tests, the cards detected more than 90% of the adulterated milk samples.  Next the technology must be tested in field settings.