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Ask a biosafety officer

How do I safely dispose of liquid cultures containing e coli?


I'm using bacteria enrichments for toxin producing e.coli O157 and the top six non-O157 shiga toxigenic e. coli. What is the best way, other than autoclaving, to safely dispose of the samples?

Answer from a Biosafety Officer:

August 19, 2013

 A simple mixture of 1 part Clorox bleach to 9 parts water is a very effective disinfectant.  Bleach/water solutions should be made fresh daily.  For liquid cultures, disinfect by adding enough concentrated bleach to result in a final mixture of 1 part bleach to 9 parts liquid culture and allow bleach to contact culture for 30 minutes.  Be sure your bleach has an EPA registration number [1].

[1] Selected EPA-registered Disinfectants, Last accessed August 15, 2013: