title: Inactivation of foodborne microorganisms using engineered water nanostructures (EWNS).
abstract: Foodborne diseases caused by the consumption of food contaminated with pathogenic microorganisms or their toxins have very serious economic and public health consequences. Here, we explored the effectiveness of a recently developed intervention method for inactivation of microorganisms on fresh produce, and food production surfaces. This method utilizes Engineered Water Nanostructures (EWNS) produced by electrospraying of water vapor. EWNS possess unique properties; they are 25 nm in diameter, remain airborne in indoor conditions for hours, contain Reactive Oxygen Species (ROS) and have very strong surface charge (on average 10 e/structure). Here, their efficacy in inactivating representative foodborne bacteria such as Escherichia coli, Salmonella enterica, and Listeria innocua, on stainless steel surfaces and on organic tomatoes, was assessed. The inactivation was facilitated using two different exposure approaches in order to optimize the delivery of EWNS to bacteria: (1) EWNS were delivered on the surfaces by diffusion and (2) a "draw through" Electrostatic Precipitator Exposure System (EPES) was developed and characterized for EWNS delivery to surfaces. Using the diffusion approach and an EWNS concentration of 24,000 #/cm3, the bacterial concentrations on the surfaces were reduced, depending on the bacterium and the surface type, by values ranging between 0.7 to 1.8 logs. Using the EPES approach and for an aerosol concentration of 50,000 #/cm3 at 90 min of exposure, results show a 1.4 log reduction for E. coli on organic tomato surfaces, as compared to the control (same conditions in regards to temperature and Relative Humidity). Furthermore, for L. innocua, the dose-response relationship was demonstrated and found to be a 0.7 and 1.2 logs removal at 12,000 and 23,000 #/cm3, respectively. The results presented here indicate that this novel, chemical-free, and environmentally friendly intervention method holds potential for development and application in the food industry, as a "green" alternative to existing disinfection methods.
authors.affiliation: †Center for Nanotechnology and Nanotoxicology Center, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, United States.
authors.forename: Georgios
authors.initials: G
authors.lastname: Pyrgiotakis
authors.affiliation: ‡Laboratory of Applied Microbiology, Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.
authors.forename: Archana
authors.initials: A
authors.lastname: Vasanthakumar
authors.affiliation: †Center for Nanotechnology and Nanotoxicology Center, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, United States.
authors.forename: Ya
authors.initials: Y
authors.lastname: Gao
authors.affiliation: §European University Cyprus, The School of Sciences, Nicosia 1516, Cyprus.
authors.forename: Mary
authors.initials: M
authors.lastname: Eleftheriadou
authors.affiliation: †Center for Nanotechnology and Nanotoxicology Center, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, United States.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Toledo
authors.affiliation: ‡Laboratory of Applied Microbiology, Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.
authors.forename: Alice
authors.initials: A
authors.lastname: DeAraujo
authors.affiliation: †Center for Nanotechnology and Nanotoxicology Center, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, United States.
authors.forename: James
authors.initials: J
authors.lastname: McDevitt
authors.affiliation: ∥Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States.
authors.forename: Taewon
authors.initials: T
authors.lastname: Han
authors.affiliation: ∥Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States.
authors.forename: Gediminas
authors.initials: G
authors.lastname: Mainelis
authors.affiliation: ‡Laboratory of Applied Microbiology, Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.
authors.forename: Ralph
authors.initials: R
authors.lastname: Mitchell
authors.affiliation: †Center for Nanotechnology and Nanotoxicology Center, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, United States.
authors.forename: Philip
authors.initials: P
authors.lastname: Demokritou
mesh_terms: D001419:Bacteria / Q000187:drug effects; D011232:Chemical Precipitation; D015169:Colony Count, Microbial; D004058:Diffusion; D005516:Food Microbiology; D018551:Solanum lycopersicum / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D013193:Stainless Steel / Q000494:pharmacology; D055672:Static Electricity; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D013193:Stainless Steel