The U.S. Department of Agriculture Agricultural Research Service (ARS) discovered that Lactobacilli that spoil dill pickles may also break down azo dyes (some of which are mutagenic) in wastewater. Microbiologist Ilenys Pérez-Diaz was looking for the culprit responsible for causing dill pickles to have a reddish spoilage. She discovered that pickle brine with tartrazine (a yellow food-coloring agent) caused the red blight on pickle skins. Since the Lactobacilli could break down tartrazine, it may also be able to break down azo dyes in wastewater, which impart colors such as red, orange and yellow to fabric. If food-grade microorganisms can degrade azo dyes, they could become the microbe of choice for wastewater plants that receive water from fabric dyeing operations.