BS EN 554:1994 download.Sterilization of medical devices Validation and routine control of sterilization by moist heat.
Introduction
A sterile product item is one which is free of viable micro-organisms. The European standards for medical devices require, when it is necessary to supply a sterile product item, that adventitious microbiological contamination of a medical device from all sources is minimized by all practical means. Even so, product items produced under standard manufacturing conditions in accordance with the requirements for quality systems for medical devices (see EN 46001 or EN 46002) may, prior to sterilization, have micro-organisms on them, albeit in low numbers. Such product items are non-sterile. The purpose of sterilization processing is to inactivate the microbiological contaminants and thereby transform the non-sterile items into sterile ones.
The inactivation of a pure culture of micro-organisms by physical and chemical agents used to sterilize medical devices often approximates to an exponential relationship; inevitably this means that there is always a finite probability that a micro-organism may survive regardless of the extent of treatment applied. For a given treatment, the probability of survival is determined by the number and resistance of micro-organisms and by the environment in which the organisms exist during treatment. It follows that the sterility of any one item in a population of items subjected to sterilization processing cannot be guaranteed and the sterility of the processed population of items has to be defined in terms of the probability of the existence of a non-sterile item in that population. The value taken by this probability is specified elsewhere (see EN 556). However, the principles specified in this standard are applicable irrespective of the stated probability.
Requirements for the quality system for the design/development, production, installation and servicing of medical devices are given in EN 46001 and EN 46002 which supplement the EN 29000 series of European Standards.
The EN 29000 series of standards designates certain processes used in manufacture as “special” if the results cannot be fully verified by subsequent inspection and testing of the product. Sterilization is an example of a special process because process efficacy cannot be verified by inspection and testing of the product. For this reason, sterilization processes have to he validated before use, the performance of the process monitored routinely and the equipment maintained.
It is important to be aware that exposure to a properly validated and accurately controlled sterilization process is not the only factor associated with the provision of reliable assurance that the product is sterile and, in this respect, suitable for its intended use. Attention has also to be given to a number of factors including the microbiological status (bioburden) of incoming raw materials andlor components, their subsequent storage and to the control of the environment in which the product is manufactured, assembled and packaged.
The object of this European Standard is standardization in the field of validation and routine monitoring of moist heat sterilization processes and procedures that are carried out by those who sterilize medical devices. The validat ion of sterilization procedures presupposes that the sterilizer complies with appropriate specifications. This standard contains requirements for the validation and routine monitoring of sterilization by moist heat; guidance on the application of this standard is offered in informative annex A.
NOTE The requirements are the obligatory parts of this standard in that these are to be observed if compliance is to be achieved. The guidance given in annex A. which includes methods accepted as being suitable for achieving compliance with the requirements, is not obligatory and it is not provided as a check list for auditors.
1 Scope
1.1 BS EN 554 specifies requirements for the process development, validation, process control and monitoring of the sterilization of medical devices using moist heat.
1.2 The method is based on the monitoring of the physical factors that cause the product to become sterile and presupposes that prior to validation the sterilizer and its installation comply with an appropriate specification.
NOTE Specifications for sterilizers are being prepared by
CEN/TC 102.
1.3 BS EN 554 does not describe a quality assurance system for the control of all stages of manufacture.
NOTE Attention is drawn to the standards for quality systems (see EN 46001 or EN 46002) which control all stages of manufacture including the sterilization process. It is not a requirement of this standard to have a complete quality system during manufacture but certain elements of such a system are required and these are normatively referenced at appropriate places in the text.
3.4
commissioning
obtaining and documenting evidence that equipment has been provided and installed in accordance with its specifications and that it functions within pre-determined limits when operated in accordance with operational instructions
3.5
equilibration time
period which elapses between the attainment of the sterilization temperature in the sterilizer chamber and the attainment of the sterilization tenzperature at all points within the load
3.6
holding time
period for which the temperature of all points within the sterilizer load is held within the sterilization temperature band
NOTE The holding time follows immediately after the equilibration time. The extent of the holding time is related to the sterilization temperature.
3.7
inoculated carrier
piece of supporting material on which a defined number of specified micro-organisms has been deposited
3.8
installation qualification
see corn missioning (3.4)
3.9
installation test
series of checks and tests performed after installation of the sterilizer in the place of use
3.10
medical device
(the definition given in EN 46001 applies)
3.11
moist heat
heat that is derived from water, either as a liquid or as steam under pressure
3.12
national standard
standard recognized by an official national decision as the basis for fixing the value(s), in a country, of all other standards of the quantity concerned
NOTE The national standard in a country is often a primary standard.
4.6.5 The calibration of temperature measurement systems used for validation shall be verified at a temperature within the sterilization temperature band before and after each programme of sequential tests.
4.6.6 Timed measurements shall be controlled to an accuracy of± 1 %.
4.7 Maintenance
4.7.1 Preventative maintenance shall be planned and performed in accordance with documented procedures. The procedure for each planned maintenance task and the frequency at which it is carried out shall be specified and documented.
4.7.2 The sterilizer shall not be used to process medical devices until all maintenance tasks have been satisfactorily completed and recorded.
4.7.3 Records of maintenance shall be retained as specified in 4.16 of EN 29001:1987 or in 4.15 of EN 29002:1987.
4.7.4 The maintenance scheme, maintenance procedures and maintenance records shall be reviewed periodically by a designated person (see 4.1).
5 Validation
5.1 General
5.1.1 Procedures for validation shall be documented.
5.1.2 C’ommissioning, performance qualification, recom in issioning and performance requalification shall be assigned to a designated person experienced in this specialism as specified in 4.1.2.1 and 4.18 of EN 29001:1987 or in 4.1.2.1 and 4.17 of EN 29002:1987.
5.2 Commissioning
5.2.1 commissioning shall demonstrate that the sterilizer and the area in which it is installed comply with the specification(s) and that the calibration of instrumentation used for control, indication and recording is within specified limits.
5.2.2 The tests and checks to be performed during commissioning shall be specified, documented and recorded.
5.3 Performance qualification
5.3.1 Performance qualification shall be performed after completion of commissioning. It shall be performed on the introduction of new or modified products, packaging, loading pattern, equipment or process parameters unless equivalence either to a validated reference load or to a previously validated product, packaging or loading pattern combination has been demonstrated.
7 Product release from sterilization
7.1 A system shall be established and maintained for release of product after sterilization. The system shall ensure that the validated sterilization cycle has been reproduced within the specified limits.
7.2 Non-conforming product shall be handled as specified in 4.13 and 4.14 of EN 4600 1:1993 or in 4.12 and 413 of EN 46002:1993.