There are strict and quite rigid hygienic requirements regarding the materials, which are meant to operate in contact with food products. Their surfaces shall not be prone to retaining contaminants. They must allow easy cleaning and sanitation. Currently there are plenty of available methods, which could be implemented to achieve this goal. Most popular and still widely used is the application of a Teflon coating. Because of its disadvantages, the global community of engineers is actively seeking for an alternative. In relation to this up-to-date problem, the article presents the results from an experimental evaluation of the hygienic performance of laser processed and sandblasted samples of AISI 316 steel. The evaluation was carried out using liquid contaminants such as tap water, cow milk, virgin olive oil and saline solution with grown Bacillus Subtilis bacteria in it. After processing the surface of the material with infrared laser and after subjecting it to chemical passivation with HNO3, ultra-hydrophobic properties were accomplished. Treatment with ultraviolet laser resulted directly in ultra-hydrophobic surface without the necessity for chemical passivation. Sandblasting was found to be ineffective in spite of how it is advertised to companies. Obtained data also set directions towards attaining oleophobic surfaces.
Gospodinov et al. (Mon,) studied this question.