• Machado, I.
• Fulgencio, R.
• Moreira, Jmr
• Oliveira, F.
• Bialuch, I.
• Mergulhao, Fj
• Melo, Lf
• Simoes, M.

Abstract

In industrial processes, particularly in the food sector, sustainability is increasingly important. Consumers demand safer food and this is often associated with elevated cleaning costs and high environmental impacts in order to reduce contaminations on equipment and products. Modified surfaces are seen as a promising strategy for biofouling mitigation and contamination prevention. In this work, the performance of a modified Diamond-Like Carbon (DLC) surface designated by SICON (R) (a-C:H:Si:O) was compared with stainless steel (316L) regarding bacterial adhesion, biofilm formation and cleanability. Assays were performed at different temperatures using Escherichia coli, one of the most persistent foodborne microorganisms and also the natural flora present in the water from an industrial salad washing line. Bacterial adhesion on SICON (R) and stainless steel were similar and favored at a higher temperature (30 degrees C). Biofilm formation was reduced on SICON (R) (1-2 Log) and this may be explained by the lower ratio between the Lifshitz-van der Waals apolar component and the electron donor component (gamma(LW)/gamma(-)) of this surface. It was also shown that after performing a cleaning treatment with chlorine, reduction of viability counts was much higher in SICON (R) (about 3.5 Log reduction and 15% removal) when compared to stainless steel (1.6 Log reduction and 6% removal). Additionally, it was observed that 18 h after treatment, biofilm values in SICON (R) were similar to those obtained with stainless steel. Results indicate that for industries with cleaning frequencies of up to 6 h, the use of SICON (R) on critical areas enables operation at a much higher hygienic level.

Topics

• impedance spectroscopy
• surface
• Carbon
• stainless steel
• washing