Some species of Lactobacilli-food-related microorganisms-can cause red colouring when combined with tartrazine, a yellow food-colouring agent used in the manufacture of dill pickles.
The new study by Ilenys Perez-Dmaz and her colleagues from the ARS Food Science Research Unit in Raleigh, N.C., indicates that Lactobacilli can transform azo dyes into non-mutagenic substances - and could be implemented in wastewater treatment applications.
Perez-Dmaz and her colleagues isolated Lactobacilli from spoiled jars of hamburger dill pickles and used those isolates to inoculate non-spoiled jars of hamburger dill pickles. Jars that contained brines with tartrazine developed the red hue on the pickle skins; those that had turmeric or no added colouring did not.
The findings from this work have been reported in the Journal of Applied Microbiology.