Exploring the Antimicrobial and Biofilm Activities of Common Food Dyes

Karla Ortiz

Co-Presenters: Individual Presentation

College: Hennings College of Science Mathematics and Technology

Major: BA.BIOLOGY

Faculty Research Mentor: Bendaoud, Meriem  

Abstract:

Synthetic dyes are widely used in the food industry to enhance the visual appeal of processed products, yet their interactions with microorganisms remain underexplored. While some dyes are biodegradable, azo dyes in particular can persist in wastewater and soil, leading to ecological consequences that threaten soil quality and aquatic ecosystems. This study evaluated the effects of commonly used synthetic food dyes, red, blue, and green, on microbial growth and biofilm formation using 96-well plate assays against multiple bacterial strains and one fungal strain. Red dye had little effect on the growth of most tested microorganisms, though it slightly inhibited Staphylococcus aureus. It also promoted biofilm formation in S. aureus, Enterococcus faecalis, and Staphylococcus epidermidis. Blue dye enhanced growth in several Gram-negative bacteria and in Candida albicans, although overall growth was minimal. In contrast, green dye consistently inhibited microbial growth, with most activity observed against Streptococcus oralis, E. faecalis, Listeria monocytogenes, and S. aureus at different concentrations. These findings highlight the diverse and sometimes opposing effects of synthetic food dyes on microbial physiology, which emphasize the importance of further research into their implications for human and environmental health.