Comparing TiO2 photocatalysis and UV-C radiation for inactivation and mutant formation of Salmonella typhimurium TA102

Abstract

Salmonellosis is one of the most common causes of foodborne bacterial human disease worldwide, and the emergence of multidrug-resistant (MDR) strains of Salmonella enterica serovar Typhimurium (S. typhimurium) was associated to the incidence of invasive salmonellosis. The objective of the present work was to investigate the effects of the TiO photocatalysis process in terms of both bacteria inactivation and the emergence of mutants, on S. typhimurium TA102 water suspensions. The TiO photocatalysis was compared with a conventional disinfection process such as UV-C radiation. In spite of the faster bacterial inactivation obtained in UV-C disinfection experiments (45, 15, and 10 min for total inactivation for initial cell density 10, 10, and 10 CFU mL, respectively), photocatalytic disinfection (60, 30, and 15 min) was more energy efficient because of a lower energy requirement (2-20 mWs cm) compared to the UV-C disinfection process (5-30 mWs cm). During the photocatalytic experiments, the mutation frequency increased up to 1648-fold compared to background level for a 10 CFU mL initial bacterial density, and mutants were inactivated after 1-10-min treatment, depending on initial bacterial cell density. In UV-C disinfection experiments, the mutation frequency increased up to 2181-fold for a 10 CFU mL initial bacterial cell density, and UV-C doses in the range of 0.5-4.8 mWs cm were necessary to decrease mutation frequency. In conclusion, both disinfection processes were effective in the inactivation of S. typhimurium cells, and mutants released into the environment can be avoided if cells are effectively inactivated.

Impact of grazing around industrial areas on milk heavy metals contamination and reproductive ovarian hormones of she-camel with assessment of some technological processes on reduction of toxic residue concentrations

“…There are several categories of contaminants such as industrial chemicals, heavy metals, persistent organic pollutants (POPs), natural toxins, endocrine disruptors, and pesticides [ 49 , 50 ]. Another name for endocrine-disrupting chemicals is endocrine-disrupting compounds (EDCs).…”

Reproductive toxicity of combined effects of endocrine disruptors on human reproduction

“…These hormones play a crucial role in maintaining homeostasis and regulating developmental processes (Kavlock et al, 1996). Several notable EDCs include antibiotics such as amoxicillin, penicillin, sulfonamides, and tetracycline, antidepressants such as citalopram and fluoxetine, non-steroidal anti-inflammatory drugs (NSAIDs) like naproxen, diclofenac, ibuprofen, contraceptive pills, various household and industrial chemicals such as alkyl phenol detergents, dioxins, fire retardants, polychlorinated biphenyls (PCBs), phthalates, and phthalate esters (PAEs) (Christensen et al, 2006;Caliman and Gavrilescu, 2009;Pal et al, 2010;Fiorentino et al, 2017).…”

Impact of Endocrine Disrupting Chemicals (EDCs) on Reproductive Health of Human

“…Human actions have introduced wide varieties of contaminants into the environment globally. These types of contaminants include different categories of organic and inorganic chemical compounds which are endocrine disruptors, natural toxins, disinfection by products (Fiorentino et al 2017), industrial chemicals, persistent organic pollutants (POPs), lifestyle compounds such as caffeine, brominated flame retardants (BFRs),artificial sweeteners and pesticides which damage human health and biota (Khan et al 2020). Endocrine-disrupting compounds (EDCs) are also known as endocrine-disrupting chemicals.…”