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Sterilization in Hospitals

Released: Thu, 06/17/2010 - 17:18 By sandeep

Sterilization in hospitals is a major concern and needs to be taken care properly. To make you aware of various issues, we would talk about it here regularly. You can also put your comments, ideas, upload the support pictures, files or presentations. The discussions are for everybody and are free. 



This is indeed a very important issue,it has occured to me at times.Talking from packaging pt of view the package may be made in an asceptic environment & the seal also might be hermetic(say syringe) but there is no way to ensure whether at the time of using the pack is intact(say no leak etc).

For this i think vacuum pack is the best solution,any damaged pack will give indication.

However consumers need to be educated.I have seen people returning a certain vacuum pack tea to the grocer complaining how the pack 'sticks'!!!

Thank you, you have a point. We would be talking here about various aspects of Sterilization in Hospitals more from the education point of view so that visitors can share their experience. We will try to cover small part everytime so that its not heavy on readers. We would cover small parts but systemeticaly. The following topics would be covered:1. What is sterility>2. Practical examples3. Sterilization methods4. Available packaging materials5. Different pouches6. Sealing machinesWe request readers, to upload their knowledge to share. If you have nay problem anytime then please do email at

Dear Sandeep,Would  like to know more about Available packaging material/ different pouches and sealing machines.RegardsAmbrish

Visit our web site and to see such products. 

Sir, just uplaoded a document on ETO Sterilization in replies n a question above, you can downlaod frome there, hope that would help.

Vacuum pack may or may not be. Its critical to sterilise. If the pack is vacuum then only method is Gamma radiation while with other packs there is also a possibility of ETO, Autoclaving. So it all depbns of the product. Depending on the product, packaging has to be selcted and then it needs to be breathable for ETO. Attached is one of my old articles on ETO. I hope this would help you all.

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As early as the 19th century it was discovered that sickness and disease are caused by bacteria. Our environment is full of bacteria and micro-organisms, but most of them are necessary to sustain life on earth. There are also bacteria in our bodies which we cannot live without, having specific tasks to perform to help the human body to function. This means that not all bacteria are bad, as long as the right ones are in the right place! There are problems only when the natural equilibrium is disturbed or when foreign bacteria enter our bodies. Then we become ill. In hospitals in general and particularly in the operating theatre there are many opportunities for bacteria to invade the human body, including those which are unwelcome. An important way of preventing this is the sterilisation of all surgical instruments.  Sterility, in this case, means absence of bacteria and micro-organisms. The following rule applies: maximum 1 micro-organism in 1 million units. We now know a great deal about the ways in which bacteria are transmitted. The best known and most common means of transmission is certainly bodily contact with objects and with other people. In order to keep such contact transmission under control we strive for a high level of hygiene (e.g. by frequent thorough hand washing) and we sterilise instruments and equipment. if we can understand why hygiene and sterility are so important in the hospital environment, our rules and routines will be more readily accepted, and any misunderstandings avoided.

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In this section we follow the handling of a surgical instrument (a pair of scissors) between operations. The scissors have been used in an operation and are then sent to be washed and disinfected. After being checked for stains or damage they are sent to the sterile packaging department where they are placed in a suitable bag or pouch. The method of insertion is important so that the scissors can later be removed in a sterile procedure. The pack is then hermetically sealed and where necessary marked with an expiry date. After sterilization, the baskets are removed from the autoclave and each pouch or pack is inspected. They must be undamaged and the steam indicators changed to the correct color. The scissors are now returned to the surgical department for storage and re-use. When the scissors are used again, the person opening the pouch must check again that it is undamaged and that the steam indicator has changed correctly. Surgical instruments are always handled separately from other goods, and some CSSD’s have a separate room where surgical instruments are controlled, counted and packed. 

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Sterilizations Methods:  Let us take a look at the different methods and why they are used. Account must be taken of what is to be sterilized, and the location. 

  1. Steam Sterilization

Use: Hospitals, care centers, private practitioners, dentists and industry. The                     method can be used on different types of material, e.g. textiles, stainless steel, rubber and certain plastics. Temperature range 1200 to 143°C.Method: The goods are put in the chamber of the autoclave and the door is closed.     The air is sucked out (evacuated) and hot steam is added under high pressure. The steam can now penetrate the packaging material and kill any micro-organisms that may be present. The pressure and the time required to achieve sterility depends on the temperature: from 4kp for about 7 mm. at 143°C, to 2kp for about 20 mm. at 120°C. When the sterilization process is complete, air is allowed to enter the chamber. The goods should now be dry.Monitoring: Nowadays many autoclaves are provided with a printer which records the temperature, time and pressure of each charge. Autoclaves without such recording arrangements have corresponding indicating instruments whose data can be transferred to a list. At regular intervals (e.g. once weekly or monthly) there should be spore tests to ensure that no micro-organisms have managed to survive. In addition every sterile package has a steam indicator which changes color, e.g. from red to brown, when exposed to high temperature and steam. On indicator tapes the color often changes from white to brown. Although these indicators do not prove that the contents are sterile, they do show that the pack has been exposed to the sterilization process. For an autoclave to function effectively it requires cleaning both on the outside and the inside. Regular service and maintenance is also important, for example on valves and gaskets. 

  1. Formaldehyde Sterilization

Use: CSSD’s and operating theatres. The method is used on materials sensitive to high temperature. Temperature 80°C.Method: The formaldehyde autoclave works under a vacuum. In the chamber steam is mixed with formalin to form gaseous formaldehyde, a substance that has bacteria killing properties. However, formaldehyde is also a poisonous and allergy developing substance. Therefore this kind of autoclave must have a special rinsing process to ensure complete removal of all formaldehyde residues.Monitoring: In addition to the usual functional monitoring and spore tests, the sterile material must be frequently examined for formaldehyde residues. There are special indicators for the formaldehyde sterilization method.  

  1. Cold Sterilization 

Use: Hospitals only. The method is used for materials that will tolerate little or no heat, e.g. certain plastic tubes and fibre optic cables. Sterilization is performed in a liquid at room temperature.Method: The cleaned items are put in a container filled with a glutaraldehyde solution that has sterilising properties. Alter remaining in the solvent for the prescribed time the items are carefully rinsed with a sterile saline solution or sterile water. Tubes must be extra carefully rinsed on the inside. Glutaraldehyde is poisonous, and therefore gloves must be used. It is also important that the ventilation in the room is good.Monitoring: Ensure that the glutaraldehyde solution is not too old, and that the full sterilisation time has been allowed. 

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            Other Methods of Sterilization:   4.        Dry Heat Sterilization Use: This method is still used occasionally in the dental field, but has several negative aspects making it relatively unpopular Temperatures required are very high (160°C to 180°C) and it takes a long time (30 mins to 2 hours). Many materials in use today cannot withstand stress of this kind.Monitoring: Time and temperature are the important factors. There are also indicators, indicator tape and spore tests for dry heat sterilization. 5.        ETO Gas Sterilization (Ethylene Oxide) Use: Industry and some big hospital CSSD’s. The method is particularly useful for heat sensitive materials as it takes place at a temperature of 55°C.Method: Air is evacuated from the sterilizing chamber and steam is added to moisten spores and bacteria. This makes them sensitive to the ethylene oxide gas which is then added. When the process is finished evacuation is performed gradually by adding air in stages. This is done to remove as many toxic remnants as possible. Sometimes it is necessary to keep the goods in a special evacuation room or cabinet after sterilization. Depending on the material, packaging and evacuation method, this can take from 12 hours to one week.Monitoring (Industry): Before the goods are sterilized a precontamination test is performed to determine the amount of organisms present. Spore tests are used in every run of the sterilizer and the goods are kept in quarantine until the analyses are finished and approved. Further tests are done by taking random samples from the sterile goods.Monitoring (CSSD): Spore tests are regularly carried out and special indicators and indicator tape are also used. 6.        Sterilization by RadiationUse: Exclusively in the industrial field. Suitable for almost all materials with the exception of certain plastics and rubber combinations, the process takes place at room temperature.Method: The method is based on a radioactive source (cobalt 60) that generates gamma rays to penetrate the goods. Alternatively an electron accelerator generating beta rays can be used. This type of equipment is very expensive and so most companies sub-contract their work to specialized sterilization plants.Monitoring: Precontamination tests are taken as with ETO sterilization, and the radiation intensity must be very carefully controlled, usually 3.2 Mrad (32kGy). Sometimes the dose can be lowered to 2.5 Mrad (25kGy), but then the goods must be random sampled to test sterility. 

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Packaging Material As a general principle (except for cold sterilization) items to be sterilized must first be packed. The sterile package has a very important job to fulfill, demanding materials with special properties. The packaging must protect the contents so that they can withstand normal handling without being damaged, and also allow sterilization to take place. It must then keep the contents sterile until such time as they are used. For factory sterilized goods the packaging must also carry information such as size, model, manufacturer, date of manufacture and expiry date. We start by looking at the packaging materials used in hospitals. Plastics Plastic materials play an important part in the manufacture of transparent pouches used in hospitals. The transparent side consists of two different thin films laminated together, making the contents visible and allowing the pouch to be sealed by heat and pressure. The outer layer of film is polyester which is very strong and has a high melting point (250°C). The inner layer; facing the paper; is polypropylene with great elasticity and a low melting point (160°C). This means that only the inner film melts when it is heat sealed, forming an internal bond with the paper. The laminated film is stable enough to survive the sterilization process, and gives good protection against recontamination. Although laminated films are always used for hospital pouches, dentists using dry heat sterilization can use pouches made only of nylon film. Paper Paper is the material most commonly used for packaging in hospitals. It is used in pouches and bags, disposable packaging sheets and in cartons. The paper used in pouches must let steam and gas pass through during the sterilization process when the paper is damp and the pressure in the autoclave is high. In dry conditions, however; the pores must be closed to keep air and micro-organisms out. This very special porosity is a unique requisite for sterile packaging paper. It must also have high wet strength, so that when the paper is wet it can withstand the powerful changes of pressure in the autoclave without breaking.The material used for wrapping paper sheets is also special. It must have the same characteristics as pouch paper but must also be easy to fold and soft. Its performance with adhesive tape is also important, both in closing and opening the package. Sterile goods must be double wrapped for good protection and to allow opening by accepted sterile procedure. Usually different colors are used (e.g. white inside and green outside), and the most common grade is crepe which is the more elastic. New non-woven is safer and more conforming, and these can be made stronger by adding artificial fibers during manufacture.  

Other Packaging Materials Textiles  Textile packaging sheets are sometimes used but this is a material which is fast losing popularity because it is not able to meet the modern demands for bacteria barrier characteristics. Textile sheets are used many times and must therefore be carefully examined for damage, when any holes must be mended by hand. This and the high cost of laundry make the use of textile sheets very expensive.Industry is able to select the best type of packaging to suit whichever method of sterilization is to be used. For example, when irradiation is to be used, the packaging can be made completely of plastic. When the contents are required to remain sterile for a longer period of time, the thickness of the packaging material can be increased accordingly. Using a special coating technique, the inner side of paper used in packaging can be covered with a special lacquer, making the paper stronger and giving a seal which is very easy to open. Factory sterilized goods must travel over long distances and withstand rough treatment. They are therefore often packed in three layers. Firstly every single item is packed, and then they are put in a dispenser box often made of thin cardboard.Finally a number of dispenser boxes are put in a transportation box. For added security the dispenser box is sometimes covered with a plastic film.An unopened dispenser box will remain sterile for a very longtime. The manufacturer will have printed the shelf life on the outside and it is today quite common to have an expiry date 5 years after sterilization. For products processed in hospital CSSD’s, the sterile time is of course different and it may also differ from hospital to hospital, due to local rules.Here are the most common:Heat sealed paper/plastic pouches —6 months.Paper and textile sheets—1 month.Paper pouches — 1 month.Sterile goods must be stored properly, and even the packaging material is good it must be handled with care. Hospitals generally have special main storage facilities for sterile goods but in the wards they may have to be kept in cabinets and on open shelves. It is important in this case not to put too many packs on top of each other and not to tie packages together with rubber bands. It is preferable if they can be stored in cool, dry conditions. 

POUCHES FOR STERILIZATION:The most common form of packaging in hospitals is the pouch or bag. We will therefore dedicate a special section for them. Pouches appear in two different combinations of material: paper/plastic and paper only. There are also rolls in paper/plastic from which suitable lengths can be cut to make individual pouches as required. Paper/Plastic These pouches come in two versions, flat and gusseted. Flat pouches are the most common and safe type. Gusseted pouches are used for extra bulky items, but the extra folds in the plastic film side make sealing difficult. The sealing machine must be capable of working through three layers of plastic laminate and this is not always possible. Therefore it is better to choose a bigger flat pouch if possible. The factory sealed short end (opening end) is often shaped like a V for easier and safer opening. When the parallel factory seals on the long sides are examined it is important to check that paper and plastic are aligned, if the plastic is not completely covering the paper, there will be a dangerous non-sterile surface on each side of the pouch when it is opened.A paper/plastic pouch is opened by gripping the plastic film in one hand, the paper in the other hand and carefully peeling apart. Due to the V-shape factory seal it is easy to get a good grip, but if the factory seals are too strong the pouch will be ripped apart when opened. However they must also not be too weak because the pouch will then explode in the autoclave during evacuation when an overpressure is caused inside the pouch.Pouches are printed with indicators that change color when exposed to the sterilization process. This indicator can be printed on the paper side or in between the laminated films on the plastic side. As indicator ink contains sulphur heavy metals and other chemical substances, the plastic side is preferred. Sulphur is a very aggressive substance and when ink printed on the paper side changes color in the autoclave the sulphur can make microscopic holes in the paper (pin holes). Before any pouch is opened checks must be made that the indicator has changed to the correct color that the pouch is undamaged and that the expiry date is still valid. Paper Paper pouches/bags are most often of the gussetted type. Some have a layer of special adhesive at the open end which can be heat sealed after filling. Others must be folded and taped. Regardless of sealing method, paper pouches cannot be peeled open and it is therefore more difficult to remove the contents in a sterile way. Results are better if the contents are wrapped in a paper sheet inside the pouch. The checks before opening are the same as for the paper/plastic pouch.  

SEALING MACHINES FOR THE PACKING OF STERILIZATION MATERIAL Sealing machines are important items of equipment for the packing of sterilization materials. There are two main types, the impulse machines which have been widely used for some time and the so-called continuo us sealers which have become much more popular in the last ten years. The impulse sealer As the name indicates, this machine works with a heat pulse. On the front side of the machine are two sealing bars that are activated by button, handle or foot pedal. When sealing a pouch, the open side is placed between the bars which are then closed. An electric pulse is sent through a copper wire running along one or both of the bars, melting the plastic and paper together under pressure. In order not to burn the pouch, the copper wire on the bars is covered with Teflon tape. When sealing is complete the bars open again. The duration of the electric pulse (heat) and the closing time of the bars are both adjustable on this type of machine. Sometimes the pressure is adjustable, too. Maintenance on an impulse sealer is fairly demanding - the Teflon tape and the copper wires must be regularly checked and replaced if necessary and it is important to check that the sealing bars are parallel for even distribution of pressure. The roll sealer This type of machine works in a far more automatic way. There is a groove that runs along the front of the machine and the open side of the pouch is put into the groove at one end. A conveyor belt grips the pouch and passes it along, firstly heating the plastic and then passing it under pressure between two wheels that bond the plastic and the paper. This type of sealing machine, working on the automatic conveyor belt principle makes it possible to feed pouches continuously into one end and receive them, sealed, at the other Adjustments can be made to temperature and, on some types, to pressure and speed to suit the type of pouch to be sealed. However, the speed of the conveyor belt is also important for a good quality seal. If it is too fast the seal will be weak, but if it is too slow the pouch will be damaged by the heat. Best operating speed is usually 6-8 meters/mm. Most sealers of this type can be put in reverse if needed, and this is useful if the packed pouch for any reason gets stuck in the groove. Very little maintenance is required on a roll sealer. 

There is no doubt that sterilization is one of the most critical issue in our healthcare industry today. Ignorance about the process of sterilization and the greed for money at the patient's cost has made the Hospital and paramedic staff into life taker instead of life savoir. This may sound rude but is a fact of life and can be easily verified in today's so called big, prestigious and five star Hospitals what to talk of small hospitals and nursing homes.There are two type of medical devices which directly come in contact with the patient and are to be sterilized before use. Type one is reusable medical device, which can be used again and again by cleaning and sterilizing them before use. Most of the surgical equipment come under this category. Autoclaving is and should be the most commonly used sterilization method for such type of medical devices. Type two is single use or disposable medical devices. These come in sterilized and ready to use packing. After use these devices should be destroyed and disposed off as per approved disposal procedure of the hospital. The grey area lies in the fact that in most of the hospitals these disposable medical devices are sterilized and reused again and again. There always remain a big question mark on the quality and efficacy of sterilization process adopted by hospitals. The ideal situation and in the interest of precious human life, disposable medical devices should never be reused as far as possible. In rare case if at all they need to be reused, then proper and appropriate sterilization method should be selected, proper facility should be installed by some reputed and knowledgeable vendor and proper and validated sterilization procedure should be used. Sterilization cycle should be continuosly monitored and only after verfication of sterility through standard methods mentioned in pharmacopias, the product should be used on the patients.

Hi all,We currently have an offer is suitable for steam sterilization and good for lamination with film. They can be used by manufacturers of sterilisation pouches. Pouches made by our paper is heat sealable and there is no paper dust when broken paper bags which is not good in Hospital when they will be pealed. They meet "Japan Industrial Standard" JIS similar to that of EN-868 part1,3&5.RegardsDeepak Chopra+91 99456 96553+91 80 26609435  

I am a QTP Qualified Test Person Autoclaves and a validation engineer for sterilisers for many years and I operated my own business in Ireland and sometimes UK. I saw steriliser services go from non existent to a now very much regulated services for Irish and Uk hospitals and pharmaceutiocal plants. I have specialised in Getinge and British Sterilisers in particular and am very conversant with EU standards and regulations and now I am available for consultancy work. I am also looking for any opportunity to start a new range of sterilisers and packaging materials for CSSD and HSSU  departments for Ireland. I welcome any advances from businesses and individuals who have an interest in having work done in hospitals on validations or the auditing of validation services and also who have autoclaves that meet EU standards and packaging  for our market. Feel free to contact me. Maybe you might be interested in JV?

I work for a tissue banking company. I do specifically packaging in medical field. Obviously sterilization is 1st order. Even if something might be a miss it will get rejected immediately. That is why it is so important. Here we can look into Gamma radiation of plastics - yes it may change integrity of packaging but its a great way to sterilize. Another substituion is using an Ethylene Oxide Gas. Not as damaging to plastic, for example a thermoformed blister pack and its components. Just food for thought.

I think we are deviating from the main topic " sterilization in Hospitals". There are many sterilization methods which can be used depending upon its suitability to the products being sterilized. These methods are:-1. EtO gas sterilization, 2. Steam sterilization, 3. Gamma sterilization, 4. Dry Heat sterilization, 5. E-beam sterilization, 6. Dry heat sterilization, 7.Low Temperature Hydrogen Peroxide Gas Plasma (LTHPGP) sterilization.Out of all above mentioned sterilization methods, only Eto gas sterilization and steam sterilization can be performed in Hospitals. Other methods are not feasible as of now. LTHPGP sterilization can be a good option but is relatively new technique.In my opinion Hospital should only opt for steam sterilization. Conversely they should re-sterilize products/medical devices which can be steam sterilized. This I am saying due to reason that steam sterilization is relatively older technique and can be carried out easily using standardized equipment and without using any hazardous material yet sterility assurance level can be achieved. I am not really with EtO gas sterilization being done in Hospitals for the simple reason that in principle it is not suitable for their application. EtO being hazardous needs to be handled with great care. The sterilizer has to be designed, manufactured and validated as per ISO 11135:2007. It should be fitted with required number of humidity sensors, temperature sensors and pressure sensors. The material to be sterilized has to be properly packed and sealed in medical grade paper or breathable film pouch and preconditioned before actual sterilization cycle starts. Complete sterilization cycle has be monitored and should be run on validated parameters. EtO indicators, spore strip or biological indicators of required K value should be used as a process challenging device placed in required numbers at critical locations in the sterilizer chamber. These sterilizers are to be placed in isolated areas. After the product is sterilized, it has to be placed in well ventilated area for 72 hours for quarantine aeration bring down the EtO gas residual level within acceptable limits. By this time Biological indicators also give the result of sterility of the sterilized load and the sterilized products can then be used safely. In hospitals I don't think there is possibility of implementing a safe EtO gas sterilization cycle as described above. And if these conditions are not met then we are playing with the patients on whom the EtO gas re-sterilized products are used. Due to this I strongly condemn the Hospitals activity of re-sterilizing the medical devices, particularly the single use medical devices by EtO sterilization in their in-house facility.     

I fully agree that ETO sterilization is tricky and should be avoided in hospitals. Its a different industry and the job should eb left with medical device suppliers,

 As we are taking about "Sterilization in Hospitals" i would like to add that my company Systech Inductions Pvt. Ltd. has made a breakthrough by successfully supplying machines for making sterilized pouches with chevron seal with or without roll form using foil paper,LDPE,HDPE,Tyvek and combined materials.

According to the increasing trends of ready to use tools in the hospitals daily activities my company develops pharmaceutical companies with a clean, sterile, pyrogen-free glass container, ready to be filled vials and cartridges. Sterlization is EtO performed and this standard sterile package is easy to manage and easy to automate format. This new products range features standard formats which are scalable to support filling solutions from the benchtop to high volume products.The brand name is “EZ-fill™ Vials and Cartridges”. Thansk to  this product hospitals can buy the exact amount of vials already sterilized  they need. The vials are sealed with a Tyvek™ sheet, package in Tyvek™/plastic steribags and case-pack allowing for sterilization with ethylene oxide. Equal attention is given to the cleanliness of the packaging components as to the production of the glass container itself. The tub, nest, Tyvek™ liner and Tyvek™/plastic steribag are all produced under ISO level 7 conditions. For details please visit

Does anybody know the answer to the following in regards to sterilization of products in a hsopital environment.1) Do the manufacturers of Sterilization Pouches, bags, roll recommend an expiry period from date of Sterilization2) Do these periods vairy in length of time3) Is there a Standard Expiry period from date of sterilization TY

yes, suppliers of sterilisable medical packaging materials do recommend the shelf life of their products. Its normally three years but you should check with individual supppliers as it also depends on the final uuse and the environment, Sandeep Goyal

Standardization of Packs Special trays and sets to be processed by CSSD should be standardized by the hospital. Surgical instruments and other related items needed for commonly practiced surgical procedure generally do not vary from surgeon to surgeon. Such operations are appendectomies, exploratory laparatomy cholecystectomies, cataract surgery, nasal surgery, ear surgery, hysterectomies, tubal ligation, etc. We should develop a composite pack for each surgical procedure, such a pack should contain all times the surgeon and nurses require for a procedure.In order that the most economic method of providing the packs can be established, cost comparisons should take place from time to time, between packs available from commercial sources and those prepared in the CSSD. The possibility of purchasing standard range of dressing packs and materials from trade sources should also be kept under review

Hiwe are a sterilizer manufacturing company. we manufacture all kinds for example steam,flash and plasma just to name a few. we are shying away from manufacturing ETO sterilizers because of the obvious reasons.i'm one of the management person in this company and i go to various hospitals as a sales person just to see what sort of sterilizing practices they follow. from what i have seen, there is immediate need for educating people in cssd first. it is shocking how many people have no idea what they are doing. they just perform a certain task coz they are asked to regardless of the well being of the victim(yes i'm using victim instead of patient). for example one of the hospitals' CSSD incharge did not know they needed to create vacuum manually in a manual autoclave and has been doing this for 13 years. now you may ask why is vacuum necessary???vacuum is essential for achievement of required temp inside the autoclaves chamber so sterilization can occur properly at 121 degree celcius. if vacuum is not created before steam enters the desired temp will not be achieved as it goes beyond the autoclaves capability to achieve that temp coz of presence of cold air inside the chamber.the reason why we know this is because we are engineering driven company and not traders like most of the present players.please visit to know more about usthnx

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