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Table 1 Correlation and detection limit of mass seq read counts with spore counts

From: Amplicon sequencing for the quantification of spoilage microbiota in complex foods including bacterial spores

OTUs

Spore spike strain

y = ax + b

Regression coefficient (R 2)

Det. limit x = (yb)/a (10log(sp/sample) at y = 1 read

Spores/sample

OTU 6

G. stearothermophilus ATCC7953

y = 0.644x − 0.5384

0.9617

0.8

7.0E+00

OTU 3

G. thermoglucosidans TNO-09.020

y = 0.7464x − 0.3915

0.9778

0.5

3.0E+00

OTU 5

G. thermoglucosidans TNO-09.020

y = 0.7222x − 0.5543

0.9348

0.8

6.0E+00

OTU 4

B. sporothermodurans IC4

y = 0.9669x − 1.9271

0.9978

2.0

9.8E+01

OTU 2

B. cereus TNO-02.0143

y = 0.9239x − 2.5864

0.9655

2.8

6.3E+02

OTU 7

B. subtilis A163

y = 1.095x − 2.9748

0.9449

2.7

5.2E+02

OTU 1

B. subtilis A163 (canned food and spike)

y = 0.011x + 3.8187

0.0111

−347.2

0.0E+00

  1. The table shows for a tenfold dilution series of spore-mix batches, the linear regression parameters (a, b, R 2) for 10log(# spores) and 10log(# reads) plotted on X- and Y-axis, respectively. R 2 indicates the quality of linearity while x at y = 1 yields the detection limit (10log(#spores) for one detected mass sequence read. Calculations are performed for each of the detected known OTUs representing the five different species in the spore-mix. Note that OTU 3 and OTU 5 both represent strain TNO-09.020