Effect of Photocatalytic and Hydrophobic Coatings on Brewery Surface Microorganisms

Abstract

The aim of this study was to determine whether process hygiene in the beverage industry could be improved by applying new coating techniques to process surfaces. Photocatalytic titanium dioxide (TiO(2)) and hydrophobic coatings applied to stainless steel with or without added antimicrobial compounds were studied in laboratory attachment tests and in a 15-month process study. No clear reductions in numbers of attached microbes were obtained with photocatalytic coatings, except for coatings to which silver had been added. These TiO(2)+Ag coatings reduced microbial coverage in laboratory studies and in some process samples. Hydrophobic coatings reduced the area coverage of microorganisms in 4-h laboratory studies but did not affect colony counts in laboratory or process studies. The surfaces had changed from hydrophobic into hydrophilic during the process study. The coatings did not mechanically fully withstand process conditions; part of the hydrophobic coatings had peeled off, most of the precipitated Ag had dissolved, and some of the TiO(2) coatings were damaged. In conclusion, functional coatings have potential for reducing microbial loads on beverage industry surfaces, but these coatings need further development.

Biofilms in the Food Industry: Health Aspects and Control Methods

“…When exposed to visible, and specially to UV light, these NPs also showed antibiofilm activity in the case of E. coli, P. aeruginosa and S. aureus , which inhibition values in the order of 2–32 μg/mL ( Nica et al, 2017 ). Similar TiO 2 NPs, although containing Ag instead of Fe and N, have been tested successfully on stainless steel surfaces (coupons) in order to prevent bacterial biofilm formation, a method of potential application in beverage industry pipelines ( Priha et al, 2011 ). This coating strategy has been more effective in the case of Gram-negative bacteria (such as Pseudomonas fluorescens ) than in the case of Gram-positive ones (such as Lactobacillus paracasei ) ( Priha et al, 2011 ).…”

Photocatalytic TiO2 and Doped TiO2 Coatings to Improve the Hygiene of Surfaces Used in Food and Beverage Processing—A Study of the Physical and Chemical Resistance of the Coatings

“…Consumer demand is driving the development of a new group of more sensitive beverages with less alcohol, hop substances, and preservatives; however, these products are more prone to spoilage than are traditional drinks [2]. There are numerous operations involved in making beer.…”

Molybdenum doped titanium dioxide photocatalytic coatings for use as hygienic surfaces: the effect of soiling on antimicrobial activity

“…Preventing the accumulation of microbial populations on process surfaces during long production runs would also reduce current cleaning costs owing to lower energy, water, and chemical consumption (Priha et al 2011). Reducing production downtime as a result of potentially less frequent or shorter cleaning times, as cleaning is made easier owing to the hydrophilic nature of the surface, would enable greater product throughput.…”

“…A similar study carried out by Priha et al (2011) to determine whether process hygiene in the beverage industry could be improved by applying TiO 2 to stainless steel with or without added antimicrobial compounds (silver) was investigated in laboratory attachment tests and in a 15-month process study. Photocatalytic coatings containing silver reduced microbial coverage in laboratory studies and in some process samples, but some of the TiO 2 coatings were damaged, and most of the precipitated Ag had eluted.…”