Fig. 3.

Linear relation between spiked and detected spores and the detection limit (spores/bacterial species/sample giving one read/OTU/sample). Normalization of the “canned food specific” OTU 8 (Aeromonas encheleia) to 340 reads/sample was applied on all other OTUs. Lines were fitted through points with >5 reads/sample) for 6 spiked OTUs not detected in pure canned food (R ² and detection limit indicated behind strain names). Additional file 2 shows normalized (and raw) frequencies of all 2037 OTUs