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.
摘要：
食品级二氧化钛(TiO2-FG)是食品工业中广泛使用的金属氧化物。最近,欧洲食品安全局得出结论认为，由于其遗传毒性，TiO2-FG不能被认为是安全的消费;然而，它对肠道微生物群的影响尚未完全阐明。我们研究了TiO2-FG（0.125mg/mL）对鼠李糖乳杆菌GG（LGG）和屎肠球菌NCIMB10415（Ent）的影响，特别是一些生理和表型性状(生长动力学，胆汁盐，和氨苄青霉素抗性)及其与宿主的相互作用(自动聚集，生物膜的形成，和对Caco-2/TC7单层的粘附）和其他肠道微生物（对病原体的抗微生物活性）。获得的结果表明，TiO2-FG改变了LGG和Ent的生长并降低了胆汁抗性（62％和34.5％，分别)和在Caco-2/TC7单层上的粘附(34.8%和14.16%，分别)。其他结果是严格的物种特异性：Ent显示较低的氨苄青霉素敏感性（14.48％）和自动聚集（38.1％），而LGG显示出减少的生物膜形成（37％）和对金黄色葡萄球菌的抗菌活性（35.73％）。总的来说,这些结果表明，TiO2-FG对内源性和外源性施用的益生菌都有不利影响，有助于反对使用TiO2-FG作为食品添加剂的论点。
