Most cycles are performed at 134°C, but some cycles are still run at 121°C for materials that cannot withstand the higher temperature. Sterilization has not been modifiedtocopewithnew pathologies (for example, AIDS, hepatitis, etc.), new microorganisms (Legionella) or new resistances such as methicillin resistant Staphylococcus aureus (MRSA) and vanco-mycin resistant enterococci (VRE). The prion (infectious protein) or non-conventional transmissible agent (NCTA) challenges laws of nature concerning its resistance, duplication and transmission. Extra measures must be applied to inactivate infectious proteins because they are not readily inactivated by conventional
equipment reprocessing methods. According to the EU, items are allowed to be called ‘sterile’ if the probability of contamination is less than, or equal to, 10-6 (EN 556) (4).