Date of Award

6-2025

Degree Name

MS in Agriculture - BioResource and Agriculture Systems

Department/Program

Bioresource and Agricultural Engineering

College

College of Agriculture, Food, and Environmental Sciences

Advisor

Peter Livingston

Advisor Department

Bioresource and Agricultural Engineering

Advisor College

College of Agriculture, Food, and Environmental Sciences

Abstract

ABSTRACT

Evaluating nanobubble-enriched water treatments for cleaning stainless steel winery tanks at the Gallo winery research station in Livingston, California.

Edgar A. Godoy-Garcia

Sanitation of stainless steel wine storage tanks is a critical component of quality control in commercial winemaking operations. Ineffective cleaning can lead to microbial contamination, product spoilage, and safety concerns. Traditionally, wineries rely on manual scrubbing, chemical cleaning agents, and extensive water rinsing cycles to maintain sanitary tank conditions. However, these methods are resource-intensive and may pose risks to both workers and the environment due to chemical exposure and wastewater generation. In response to growing industry interest in sustainable technologies, this study investigated the use of nanobubble (NB) technology as an alternative cleaning strategy for winery tanks. Nanobubbles are submicron gas cavities in aqueous solutions that exhibit unique physicochemical properties, including long-term stability, high internal pressure, and reactive radical generation upon collapse, making them attractive candidates for cleaning and sanitation applications. The research was conducted in two phases: a laboratory-scale bench experiment and a full-scale winery field trial. In the lab study, stainless steel test strips were soiled for four months with red wine lees and cleaned spraying nanobubble-enriched water generated with compressed air, oxygen (O₂), or carbon dioxide (CO₂). Cleaning efficacy was evaluated using ImageJ to analyze pre- and post-cleaning photographs. Although oxygen nanobubbles showed the greatest reductions in red and blue pixel intensities, suggesting darker post-cleaning surfaces, statistical differences among treatments were limited. Moreover, interpreting these brightness shifts proved challenging, as darker surfaces may result from pigment removal, residue oxidation, or uneven redistribution. Thus, the image analysis results were inconclusive, and reduced brightness could not be definitively linked to cleaning effectiveness. The winery-scale trial evaluated five cleaning treatments applied to 658-gallon stainless steel tanks soiled for one hour with a consistent organic load referred to as distilling material (DM). The treatments included: (1) nanobubble-enriched water with compressed air, (2) nanobubble-enriched water with CO₂, (3) a chemical oxidizing sanitizer (Sterox), (4) a manual hand-scrubbing protocol reflective of standard winery practice, and (5) a hot water rinsed untreated control. Cleaning effectiveness was quantified using adenosine triphosphate (ATP) bioluminescence measurements to assess residual microbial contamination. ATP readings demonstrated that the NB + air treatment significantly reduced surface contamination and performed comparably to both the chemical sanitizer and manual scrubbing. Overall, results from both lab and winery trials indicate that nanobubble-enriched water, particularly with air, can achieve effective cleaning performance without the use of harsh chemicals or excessive manual labor. The implementation of nanobubble technology offers a sustainable, low-impact alternative for wineries seeking to reduce chemical usage, labor intensity, and water consumption while maintaining sanitation standards. These findings contribute to the advancement of environmentally responsible cleaning practices in the food and beverage industry and lay the groundwork for broader adoption of nanobubble systems in commercial winery operations.

Keywords: winery, stainless steel, tanks, cleaning, nanobubbles, soiling, nanobubble technology, ATP bioluminescence, ImageJ analysis.

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