title: Antimicrobial effects of silver nanoparticles against bacterial cells adhered to stainless steel surfaces.
abstract: Given the increasing number of antibiotic-resistant bacteria and the need to synthesize new antimicrobials, silver has attracted interest in the scientific community because of its recognized antimicrobial activity. This study aimed to evaluate the antimicrobial effects of silver nanoparticles  (NP) obtained by a new method and tested at concentrations of 6 μg/ml and 60 μg/ml against the species Staphylococcus aureus, Listeria innocua, Salmonella Choleraesuis, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus. The ability of these nanoparticles  to remove or kill vegetative cells adhered to stainless steel surfaces was also evaluated. We observed that the NP obtained with the new method, concentrated silver nanoparticles (CNP), and silver nanoparticles with added sodium chloride (NPNaCl) had high antimicrobial activities (P  < 0.05). We also verified that the most effective condition for the removal of P. aeruginosa cells on stainless steel coupons (10 by 10 mm) was immersion of the surfaces in CNP. The CNP treatment produced a 5-log reduction of the microbial population after 30 to 60 min of immersion.  The CNP treatment also performed better than water and sodium carbonate, a compound commonly applied in clean-in-place procedures in the food industry, in removing adherent B. cereus cells from stainless steel cylinders. Therefore, these results suggest that NP synthesized by a new  procedure may be used as antimicrobials in the food industry, for example, for the sanitization of utensils that come into contact with foods.
authors.affiliation: Food Technology Department, Federal University of Viçosa, 36570-000, Viçosa, Minas Gerais, Brazil.
authors.forename: Emiliane A
authors.initials: EA
authors.lastname: Araújo
authors.forename: Nélio J
authors.initials: NJ
authors.lastname: Andrade
authors.forename: Luis Henrique M
authors.initials: LH
authors.lastname: da Silva
authors.forename: Patrícia C
authors.initials: PC
authors.lastname: Bernardes
authors.forename: Alvaro V N
authors.initials: AV
authors.lastname: de C Teixeira
authors.forename: João Paulo N
authors.initials: JP
authors.lastname: de Sá
authors.forename: José Felício Q
authors.initials: JF
authors.lastname: Fialho
authors.forename: Patrícia E
authors.initials: PE
authors.lastname: Fernandes
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D001422:Bacterial Adhesion / Q000187:drug effects*; D018407:Bacterial Physiological Phenomena; D015169:Colony Count, Microbial; D004203:Disinfection / Q000379:methods; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D004866:Equipment Contamination / Q000517:prevention & control*; D005506:Food Contamination / Q000517:prevention & control; D006801:Humans; D053768:Metal Nanoparticles; D012834:Silver / Q000494:pharmacology*; D013193:Stainless Steel
chemical_list: D000900:Anti-Bacterial Agents; D013193:Stainless Steel; D012834:Silver