Table 1.
Correlation and detection limit of mass seq read counts with spore counts
| OTUs | Spore spike strain | y = ax + b | Regression coefficient (R 2) | Det. limit x = (y−b)/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 |
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