Patients are positioned supine in a standard operating theatre, with active laminar flow and surgical lamps . An operating drape will be set up at the level of the patient's waist to ensure minimal contamination by the patients breathing. Both knees are disinfected using a curcumin coloured solution of 0,5% chlorhexidine in 96% ethanol applied in a painting motion in 2 sessions of 10 seconds separated by a 30 second drying period. The disinfected area is then left to completely dry. Disinfection is followed by standard covering of the areas adjacent to the surgical site using surgical drapes. One knee is subsequently draped with an iodine plastic adhesive drape (Ioban 2), while the other knee is left uncovered. Application of the drape is done in accordance with 3M guidelines.(11) If the participant has long hair on the legs, these are trimmed using electrical clippers prior to the intervention. The patient is then asked to remain supine on the operating table for 75 minutes. Following disinfection and subsequent draping of both knees, the operating table is placed the beach-chair position and the patient is offered a pillow to support their knees. This is placed under the surgical drapes. The beach-chair position minimizes the discomfort of having to stay supine by elevating the patient's head and ensuring some flexion of the knees. The patient is allowed to move their legs in a controlled manner, so as not to contaminate the contralateral knee. Both knees must be moved equally to ensure equal stress on the skin of the sampling site during intervention. The patient´s torso is covered with a "Bair Hugger" blanket to prevent hypothermia.