Method for checking the condition of human or animal skin

Method for checking the skin surface of a human or an animal for contamination, such as checking the teat of a cow's udder for contamination by manure, wherein one or more sources of electromagnetic radiation are directed onto the skin surface to be tested and transmit electromagnetic oscillation towards said surface, whilst one or more receivers for electromagnetic radiation are likewise directed onto the said skin surface, for receiving electromagnetic radiation originating from the said skin surface, and wherein measurement is carried out in the electromagnetic radiation range in which a clear difference is found between the radiation intensity reflected by a skin surface without contamination or having a moist contamination and that having an essentially dry contamination.