Help EO sterilization & bioburden

Ted Burrows ted at
Mon Nov 24 14:07:32 EST 1997

> From: Emanuel Meron <ms_comp at>
> Our company manufactures a medical device (single use instrument cover).
> The device is sterilized by a contract sterilizer. Sterilization is by
> Ethylene Oxide. Process was validated per EN 550. At validation time
> bioburden was 10 to 15 CFU per unit product. 
> My question is: How high may product bioburden go without invalidating
> the sterilization process? I know that the lower the bioburden the
> better but I still need to set some practical limit for our production
> people without imposing undue difficulties.
> All help will be appreciated.
> Emanuel Meron

How long is a piece of string? I would suggest that the only way you will 
get a reliable answer would be to carry out a series of controlled testing 
using spiked articles and fully documenting your results.

If carried out correctly the results should satisfy any inspectorate.

Ted Burrows. Registered Authorised Person (Sterilizers)
Integrated Designs - Thermal Validation Specialistsalists

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