1922 McLeod & Gordon
"Production of Hydrogen Peroxide by Bacteria"
James Walter McLeod and John Gordon
Biochemical Journal
Volume 16 (4)
Pages 499-506
PMID: 16743107 [PubMed]

A quote from the following paper...
"The inhibitory substance developed in pneumococcal cultures to which there is abundant access of oxygen is H2O2...  The early death of pneumococcus in culture is usually due to accumulation of excess H2O2.  The green or yellow colorations produced on heated blood media by certain bacteria are due to H2O2 formation."

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