autoclave protocols

Fri Sep 20 17:34:11 EST 1996

Amarki writes,

<Is it really necessary to maintain an autoclave log in a QA/QC 
microbiology laboratory?  I am a new graduate with a degree in 
microbiology and just recently accepted a job as an associate 
microbiologist in a pharmaceutical company.  I have worked with other 
laboratories who were either regulated by CLIA or EPA that do require log 
books for autoclave.>

Brian Hoyle answers,

<Yes, an autoclave log should be maintained. Such a log will aid in 
tracking the source of a contamination problem, and will be helpful in 
tracking the performance of the autoclave. We also do performance tests 
on our autoclaves each month (autoclave Bacillus spores, then cultrue the 
spore solution; no growth indicates autoclave is performing properly). 
Records and performance tests are not that hard or expensive to do. But 
the resulting data is valuable.>

Hey Amarki, congrats on your new degree and job. I'm still working on the 
degree, but I work in a pharmaceutical QA/QC microbiology lab. Prior to 
this I worked in a contract testing lab which had some pharmaceutical 
company clients, meaning, the place was regulated as if it were a 
pharmaceutical company.  First of all, I agree totally with Brian's reply 
regarding the value of collecting data on autoclave performance. I've 
done the Bacillus testing as well, both with the spores on spore strips 
and in liquid ampules (both B. stearothermophilus). But autoclave logs 
are easy enough to maintain. The autoclaves I've used have had charts on 
them which record each cycle (temperature, pressure, and length of 
cycle), though one had a digital readout and produced a  printout that 
looked like a grocery receipt until you looked closely and saw 
minute-by-minute printouts of the temperature and pressure. In any case,  
it's an easy enough matter to write on a chart (or printout) what's being 
run in the cycle, such as media type/batch number, discards, equipment 
you're sterilizing, etc. Then you keep the charts or printouts on file in 
the lab. Not only can you track the history of your autoclave's 
performance this way, should it malfunction, you can show the data to the 
service person when you call to have it fixed. 

Also it's a good idea (required too, at least where I've worked), in 
addition to regularly including B. stearothermophilus bioindicators,  to 
have the autoclave validated annually for the types of cycles you run. 
This means wiring up the autoclave with thermocouples set in various 
locations in the autoclave, testing both one or more empty cycles and 
"full cycles" -   putting thermocouples through bottles of media  (to 
make sure the media is being heated to the proper 121C all the way 
through). I've assisted in these validations, though I do not yet possess 
the ability to do it completely on my own at this point. The data 
gathered from these validations is used to determine how much time you 
should autoclave particular loads (notably volumes; larger volumes need 
more time),  and where to place the items inside the autoclave to ensure 
sterilization (some autoclaves have "cold spots" best to be avoided), 
among other things. The results of autoclave validations, in addition to 
the aforementioned bioindicator tests and charts of individual cycles 
should all be kept.

Have fun!


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