autoclave help!

[takeone]

i bought a cheap autoclave from ebay to sterilize vials etc.its one shaped like a metal barrel with lid on top.

i bought some autoclave pouches aswell & i put the vials in the pouch & seal but after ive finished sterilizing the pouch has a bit of condensation init.

the autoclave does not have a drying cycle like lab ones would but the condensation does go,i use the pouches cos they keep anything inside sterile till you open.

my question is will the condensation gathered in the pouch be unsterile but as i say it does evaporate.
so will the vials be sterile till opened?

many thanks for any help as im just not sure on this one

[basskiller]

I would have to say yes if the condensation formed inside while during the sterilization process ..
But that is a guess, I ask my Chem buddy



The World of Autoclaves

The autoclave is a common piece of lab equipment which has several important functions. The quality and safety of the work done in lab that works with biohazards depends on the proper use and care of the autoclave. These three articles describe the fundamentals and care of autoclaves, and show what can happen when something goes wrong.

Autoclave Action

Sterilization is defined as the complete destruction of all forms of microbial life, including bacterial spores. The meaning of this word is absolute; there is no such thing as "partial sterilization." Something is either sterile or non-sterile. Sterilization can be accomplished by either physical or chemical means. The principal physical means is autoclaving; other physical methods include boiling and dry heat. Chemicals used for sterilization include the gases ethylene oxide and formaldehyde, and liquids such as glutaraldehyde. Of all these sterilants, autoclaving is the fastest and most reliable.

Why is an autoclave such an effective sterilizer? An autoclave is a large pressure cooker; it operates by using steam under pressure as the sterilizing agent. High pressures enable steam to reach high temperatures, thus increasing its heat content and killing power. Most of the heating power of steam comes from its latent heat of vaporization. This is the amount of heat required to convert boiling water to steam. This amount of heat is large compared to that required to make water hot. For example, it takes 80 calories to make 1 liter of water boil, but 540 calories to convert that boiling water to steam. Therefore, steam at 100º C has almost seven times more heat than boiling water. Steam is able to penetrate objects with cooler temperatures because once the steam contacts a cooler surface it immediately condenses to water, producing a concomitant 1,870 fold decrease in steam volume. This creates negative pressure at the point of condensation and draws more steam to the area. Condensations continues so long as the temperature of the condensing surface is less than that of steam. These properties ensure rapid heating of surfaces, good penetration of dense materials, and coagulation of proteins.

Moist heat is thought to kill microorganisms by causing coagulation of essential proteins. Death rate is directly proportional to the concentration of microorganisms at any given time. The time required to kill a known population of microorganisms in a specific suspension at a particular temperature is referred to as thermal death time (TDT). Increasing the temperature decreases TDT, and lowering the temperature increases TDT. Processes conducted at high temperatures for short periods of time are preferred over lower temperatures for longer times.

Environmental conditions also influence TDT. Increased heat causes increased toxicity of metabolic products and toxins. TDT decreases with pronounced acidic or basic pHs. However, fats and oils slow heat penetration and increase TDT. It must be remembered that thermal death times are not precise values; they measure the effectiveness and rapidity of a sterilization process.

Autoclaving is the most effective and most efficient means of sterilization. All autoclaves operate on a time/temperature relationship. These two variables are extremely important. Higher temperatures ensure more rapid killing. Some standard temperature/pressures employed are 115ºC/10 p.s.i., 121ºC/15 p.s.i., and 132ºC/27 p.s.i. Longer times are needed for larger loads, large volumes of liquid, and more dense materials. Autoclaving is ideal for sterilizing biohazardous waste, surgical dressings, glassware, many types of microbiologic media, liquids, and many other things. However, certain items, such as fiber-optic endoscopes, cannot withstand autoclaving and should be sterilized with chemical or gas sterilants. When proper conditions and time are employed, no living organisms will survive a trip through an autoclave.

by Liam Sullivan

from: Safe Science, Michigan State Univ. July 1993



Is Your Autoclave Working Properly?

Biological waste is an important occupational hazard for people who work with the waste products of research. In addition, infectious waste is currently regulated by both the Vermont Hazardous Waste Management and Solid Waste Management regulations. It is very important that we be able to assure that we are not sending viable biohazardous organisms to the landfill. So, the Risk Management Department and the Institutional Biosafety Committee (IBC) are working together to develop a University-wide autoclave certification protocol.

If adequate steam does not come into contact with the biohazardous materials, microorganisms can survive a trip through the autoclave. Autoclave tape is not a reliable means to determine if the time, temperature, and pressure combination of the process was adequate to penetrate and kill microorganisms contained within the load. In order to validate autoclave operations, we recommend using vials containing Bacillus stearo-thermophilus spores. The Hazardous Waste Management Office will provide these vials free of charge to all departments that request them.

When checking your autoclave, follow the instructions that accompany the vials carefully. This autoclave evaluation procedure should be conducted at appropriate intervals; the frequency will depend on how often your particular autoclave is being used. We recommend that these quality control tests be done at least monthly.

In addition to this periodic autoclave testing, the Risk Management Department and the IBC recommend annual certification of the autoclave mechanical and monitoring systems. We are in the process of developing a centralized system to certify autoclaves which may be similar to the current annual biosafety cabinet certification. To this end, the current list of campus autoclaves is given in the acocmpanying table. If you have an autoclave that is not on the list, please let us know.

With the increasing concern for safe handling and disposal of infectious wastes, we must take the time and make the effort to ensure that our autoclaves are working properly. Please contact Milly Archer, Hazardous Waste Manager, at 6-5402 with any questions or comments concerning autoclave testing and certification procedures.

-Milly Archer

An Autoclave Accident

Because autoclaves generate so much energy while doing their work, the hazards they present are not to be underestimated. A recent accident on campus highlights some of the potential problems.

While preparing for the next day's work at the end of the day, a lab tech removed a 5 liter container of sterile water from the autoclave before it had a chance to cool. She put it on the counter and was turning away when the container exploded. The top of the container knocked a ceiling tile out of the ceiling. The water, which was still about 200 degrees Fahrenheit, doused the lab tech's arms, legs and abdomen. She suffered severe second degree burns of the abdomen and leg, including sizeable loss of skin on the right leg. Because this occurred at a site outside the campus phone system, she had to find the emergency number in the phone book. After finding the phone number, she was able to call UVM Rescue for assistance and had the presence of mind to disrobe and start first aid by entering a nearby tepid shower. Partial recovery required 3 weeks of synthetic skin applications to the right leg to promote skin regrowth. Complete recovery will take months.

Lessons to be learned from this incident include:

1. In addition to gloves and glasses, temperature protecting aprons should be worn when handling hot vessels. Plan the work so that handling of hot liquids is minimized. Remember the 6 P's: Prior Planning Prevents Painfully Poor Performance.

2. Autoclave use should be carefully planned to allow cooling of materials requiring sterilization before they are removed from the autoclave. If the volume of material to be autoclaved makes this difficult, it may be necessary to acquire another or a larger autoclave.

3. Response to contamination is to disrobe quickly. Because the tech was wearing clog shoes, she was able to kick them off immediately and disrobe quickly. Consequently, she suffered little foot damage. Normal shoes would not have been able to be removed as quickly because she was attending to her other injuries.

4. Emergency numbers should be posted along with information identifying the location of the lab. The lab tech had to describe the location of the lab to UVM Rescue.

5. Supervision of workers at satellite facilities is important. The worker was alone when the accident occurred, which is sometimes unavoidable. If the accident had been more serious, to the point where the lab tech was unable to summon help and start first aid, the situation would have been much more serious. If you must work in a situation where you are alone, be sure that someone knows where you are and plan carefully how you will summon help. It is best to have someone check on you if you haven't contacted them by a certain time.

While the consequences of this accident were serious, fast action by the lab tech averted much more serious damage.

- Jane O'Neil and Ralph Stuart

[basskiller]

just some help about a-claves

http://roundtable.healthsafe.uab.edu...ng%20Final.ppt

[takeone]

thanks basskiller for the info,well appreciated

an autoclave is something that needs some respect as i would not want one to explode in my house!

i did read that the pouch should be dry before being removed so instruments in bag would not tear the paper side of the pouch,making it unsterile.

so im thinking this wont apply with glass vials as they have no sharp edges that may tear pouch.

one worry might be the wet paper side may soak up bacteria if it comes in contact?i just dont know?

if you could ask your buddy that would be great as i dont want to mess up,

thanks,

[~R~F~G~]

I use one for sterilizing tattoo equipment. Never had an issue with the moisture. No infections or any issues at all. Just let the packs dry completely before you use them.

[takeone]

Originally Posted by ~R~F~G~

I use one for sterilizing tattoo equipment. Never had an issue with the moisture. No infections or any issues at all. Just let the packs dry completely before you use them.

do you mean that you have had moisture in the pouches but its no problem if dried out?

thanks for your help!

[~R~F~G~]

Originally Posted by takeone

do you mean that you have had moisture in the pouches but its no problem if dried out?

thanks for your help!

Exactly, before all these sealed sterile one use tubes and the price of needles dropped enough we had to sharpen and resterilize everything.. Wasnt cost effective to throw it away.. I still have and use mine for the metal tubes that I use.. You can't get around the moisture... So sterilize them pull them out and set them aside to cool.. The moisture goes away and nothing in the pack is unsterile.. One reason you need to use distilled water.

[samax64]

Instead of using a auto clave for your vials clean them dip them in 91%alcohol then bake them at 450 for 30 Min's and you will be good to go... You could have saved the money on the auto clave as well buy buying a pressure cooker if it doesn't have a drying cycle on it

[takeone]

yeah i know what your saying but ive got a dispenser & other things that need to be autoclaved & i do like the idea of having everything in seperate bags sterilized ready to be used whenever.

thanks for all your help everyone!i see im going to enjoy this board!!

[Yesterday's_Hero]

If your just sterilizing some glassware or something like that, for personal use, open the door part way and let the water evaporate off as it cools. You will also want to clean your work surfaces with Lysol or some other dimethylbenzyl ammonium chloride type disinfectant. Cross contamination is one of your biggest worries.

If you want true sterility, you will need a clean room with air filtration and a ton of other controls in place.

I would strongly recommend running a spore check. There are a lot of things that can go wrong in an autoclave or chemclave that you would never know about otherwise. Also, make sure you run it at over 20lbs for 30min (that was the standard here in CA last time I checked).

Personally, I would avoid the dry heat method unless I was in a pinch and would never use it where someone else's blood was involved. It is not as effective as an autoclave and even an autoclave has its short comings (prions for example).