Document Type


Date of Award



College of Science, Engineering, and Technology (COSET)

Degree Name

Ph.D. in Environmental Toxicology

Committee Chairperson

Mahmoud Saleh Fawzia Abdel-Rahman, Desiree Jackson, Bobby Wilson

Committee Member 1

Fawzia Abdel-Rahman

Committee Member 2

Desiree Jackson

Committee Member 3

Bobby Wilson


Chronic toxicity, egg laying, lifespan, nematode, progeny, Synthetic food coloring dyes


Food coloring dyes are substances known to enhance the appearance of food or drink by imparting color when it is added. They have been in large commercial food production as well as in its use in domestic food applications and non-food applications. The toxic effects of food coloring dyes have been seen in the enzymatic breakdown of the azo linkage of the dye molecule by enzyme; azo reductase. The degradation of such food dye products give rise to increased toxic effects that affect the nervous system.

Caenorhabditis elegans is a bacterial feeder, free-living soil nematode used as a model organism to investigate the chronic effects of the exposure of food coloring dyes on its biological life functions. C. elegans have closely related genetics to that of humans, with 60 to 75% of human genes identified as disease-related and possess C. elegans analogs. Research studies have shown that children exposed to different food coloring dyes exhibited ADHD as result of exposures to food coloring dyes (Boris M, et al). The different food coloring dyes used for this analysis contain the active food dye ingredients; Allura Red, Brilliant Blue, Tartrazine in varying compositions and are evaluated for their chronic effects.

This study aimed to determine the toxicological endpoints of food coloring dyes; Red coloring dye, Yellow coloring dye, Green coloring dye, Orange coloring dye on the biological life functions of C. elegans such as locomotion, egg laying, egg hatching, progeny size, lifespan, pharyngeal pumping, generation time. In these analyses, toxicity evaluation of the food coloring dyes in C. elegans showed the presence of reproductive toxicity in the egg-laying, egg-hatching and brood size assays with results showing Red food coloring dye with main active dye ingredient, Allura Red having the highest reproductive toxicity. These data show that treatment of C. elegans in the early stages of growth is also detrimental in bringing about damage to reproductive organs. Behavioral changes as a result of chronic exposure to Red coloring dye, Yellow coloring dye, Green coloring dye, Orange coloring dye were seen in the locomotion and esophageal pumping assays with significant statistical differences between the treatment groups and the control group.

The lifespan of C. elegans suffered detrimental effects with Orange food coloring dye showing the lowest life span, having main active dye ingredient, Tartrazine. Thus, the reproductive changes and behavioral modifications that occurred due to the exposure of C. elegans to Red coloring dye, Yellow coloring dye, Green coloring dye, Orange coloring dye resulted in detrimental effects to the biological life functions of the C. elegans.


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