Related Experiment Video
Updated: Aug 9, 2026

Oral Biofilm Formation on Different Materials for Dental Implants
Published on: June 24, 2018
Food-grade titanium dioxide can affect microbiota physiology, adhesion capability, and interbacterial interactions: A
F Bietto1, R Scardaci1, M Brovia1
1Laboratory of Microbial Biochemistry and Proteomics, Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Torino, Italy.
Abstract:
Food-grade titanium dioxide (TiO2-FG) is a widespread metal oxide used in the food industries. Recently, the European Food Safety Authority concluded that TiO2-FG cannot be considered safe for consumption due to its genotoxicity; however, its effect on the gut microbiota has not yet been completely unraveled. We studied the effects of TiO2-FG (0.125 mg/mL) on Lactobacillus rhamnosus GG (LGG) and Enterococcus faecium NCIMB10415 (Ent), in particular some physiological and phenotypic traits (growth kinetics, bile salts, and ampicillin resistance) and their interactions with the host (auto-aggregation, biofilm formation, and adhesion on Caco-2/TC7 monolayers) and other gut microorganisms (antimicrobial activity towards pathogens). The results obtained revealed that TiO2-FG alters both LGG and Ent growth and lowers bile resistance (62 and 34.5%, respectively) and adhesion on Caco-2/TC7 monolayers (34.8 and 14.16%, respectively). The other outcomes were strictly species-specific: Ent showed a lower ampicillin sensitivity (14.48%) and auto-aggregation (38.1%), while LGG showed a reduced biofilm formation (37%) and antimicrobial activity towards Staphylococcus aureus (35.73%). Overall, these results suggest an adverse effect of TiO2-FG on both the endogenous and exogenously administered probiotics, contributing to the argument against using TiO2-FG as a food additive.
Related Concept Videos
Microbial Corrosion
Introduction to the Human Microbiota
The Oral Microbiota
Functions of the Gut Microbiota
Dysbiosis of the Gut Microbiota
Microbiota Modulation by Antibiotics

