Figure 3
![Figure 3](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1471-2180-9-152/MediaObjects/12866_2008_Article_823_Fig3_HTML.jpg)
Correlation between luminescence and bacterial numbers at various densities in black microcentrifuge tubes. Correlation of photon-emitting Salmonella typhimurium and lux plasmid (pAK1-lux, pXEN-1, or pCGLS-1) following imaging of 1 ml aliquots in black microcentrifuge tubes (Panel A) high density (P > 0.05), (Panel B) medium density (P < 0.05), (Panel C) low density of bacteria (P > 0.05).