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.

A Critical Review of in Vitro Dosimetry for Engineered Nanomaterials

“…The growing number of engineered nanomaterials (ENMs) utilized in a wide variety of consumer products and biomedical applications has led to increasing concerns of environmental and occupational exposures [1][2][3][4][5][6][7]. The unique physicochemical properties that distinguish ENMs from their micron-sized counterparts (reactive surface area, surface energy, mobility, quantum size effects, etc.)…”

Nanotechnology to the rescue: using nano-enabled approaches in microbiological food safety and quality

“…[82] Their high surface charge makes possible the targeted delivery of the EWNS on the surface of interest, maximizing their efficiency. [24,83] In recent studies their antimicrobial potential was assessed on a representative panel of food-related microorganisms reaching inactivations up to 4 logs (99.99% reduction) without affecting sensory quality of food or leaving chemical traces making it an ideal technology for chemical free applications. [83] In addition, it has very low power demands and has been shown by an acute inhalation toxicological study to possess no apparent health effects to humans when EWNS are inhaled.…”

Effects of engineered nanomaterial exposure on macrophage innate immune function

“…A large and increasing variety of engineered nanomaterials (ENMs) are now common components of many industrial and consumer products [1–3], and more are being designed for novel diagnostic, antimicrobial, and therapeutic applications [4–11]. As such, the potential for workplace or environmental exposure to ENMs during their production and the life-cycle of products containing them, and for intentional exposure to therapeutic ENMs, is great [12–14].…”