Cleaning surfaces from food residues with pulsed laser

Currently, cleaning of food residues is mostly performed with water-based technologies. In the future, however, waterfree methods such as treatments by laser could gain importance for achieving environmental sustainability. In this study the possibility of removing food residues on surfaces with nanosecond laser pulses is discussed. The investigation was limited to three substrates: stainless steel, ceramic and glass. Coatings of black tea, caramelized sugar and onion skin brew were selected as representative contamination layers. Laser treatment was performed with a pulsed nanosecond laser system at 1064 nm wavelength. Parameters for a thorough cleaning of the substrate without surface modification were found for black tea and onion skin brew coatings. It was found that only a little amount of laser irradiation is absorbed by the contamination and that the cleaning process is initiated mainly by the substrate’s heat up. Details of the removal process and approaches to remove also a (semi-) transparent sugar coating will be discussed.