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Ask a biosafety officer

Will cultivating microbes in a petri dish with Sheep Blood agar be a bad idea in a general sense?

Answer from a Biosafety Officer:

June 10, 2013

While it is true that different species of microbes grow preferentially on different types of growth media, one of the first steps in your risk assessment should be to determine what type of samples you will be cultivating.  Are you planning to culture known microorganisms?  If so, risk group 1 organisms would be most appropriate if you will not be using Biosafety Level 2 practices and facilities (1). 

If you are planning to culture environmental, human, or unknown samples biosafety guidelines recommend using Biosafety Level 2 (BSL-2) practices and facilities regardless of the type of growth medium that you plan to use (2:  Section II:  Biological Risk Assessment; 3:  Isolation of Unknown Microbes from the Environment). 


1.     American Biological Safety Association Risk Group Database.  Accessed 03/01/2013.

2.     Wilson, D., and L. Chosewood, editors.  Biosafety in Microbiological and Biomedical Laboratories (BMBL), 5th edition.  Centers for Disease Control and Prevention and National Institutes of Health.  2009.  Accessed 03/03/2013.

3.     American Society for Microbiology.  Draft Guidelines for Biosafety in Teaching Laboratories.  2012.  Accessed 03/03/2013.