Proving the antimicrobial spectrum of an amphoteric surfactant-sol-gel coating: a food-borne pathogen study.
An antimicrobial coating was evaluated in this work for its antimicrobial efficacy against common food-borne pathogens. Dodecyl-di(aminoethyl)-glycine, an organic disinfectant, was immobilized in a silicon oxide matrix to generate thin films over surfaces by means of the sol-gel process. Tetraethoxysilane was used as the polymeric precursor. No alteration of optical transparency on the covered surfaces was observed. Topographic images obtained with atomic force microscopy showed a homogeneous film with no additional roughness added by the polymer to the surface. The attenuated total reflectance-Fourier transform infrared spectral data showed the presence of dodecyl-di(aminoethyl)-glycine in the silicon oxide network after a normal cleaning procedure. The antimicrobial efficacy test was performed by exposing coated slides to suspensions of common food-borne pathogens: Escherichia coli, Staphyloccocus aureus, E. coli O157:H7, Salmonella typhi, S. cholerasuiss, Listeria innocua and L. monocytogenes. The coating activity was not only bacteriostatic but also bactericidal. The percent reduction of viable microorganism exposure over 24 h to the coated surface ranged between 99.5%, for the more resistant gram-positive bacteria, and over 99.999%, for most gram-negative bacteria. The silicon matrix itself did not account for any reduction of viable microbial, even more an increase was observed.
Copello
G J
GJ
Cátedra de Química Analítica Instrumental, Universidad de Buenos Aires (UBA), Facultad de Farmacia y Bioquímica, Junín 956 - Piso 3 masculine (1113), Buenos Aires, Argentina.
Teves
S
S
Degrossi
J
J
D'Aquino
M
M
Desimone
M F
MF
Díaz
L E
LE
D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D015169:Colony Count, Microbial; D004202:Disinfectants / Q000737:chemistry / Q000494:pharmacology*; D019649:Food Industry / Q000379:methods; D005516:Food Microbiology; D005782:Gels / Q000737:chemistry / Q000494:pharmacology*; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D018625:Microscopy, Atomic Force; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology*
D000890:Anti-Infective Agents; D004202:Disinfectants; D005782:Gels; D013501:Surface-Active Agents; C004206:dodicin; D005998:Glycine