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Table 4 Detection of E. sakazakii in inoculated infant formula samples

From: A robotic DNA purification protocol and real-time PCR for the detection of Enterobacter sakazakii in powdered infant formulae

 

ATCC 29544

ATCC 51329

  

ISO

real-time PCR (C T values)

 

ISO

real-time PCR (C T values)

Powdered Infant Formula

Seeding level (CFU/25 g)

 

BPW

BPW-mLST

Seeding level (CFU/25 g)

 

BPW

BPW-mLST

 

0

- -

- -

- -

0

- -

- -

- -

 

4

+++

17.68 ± 1.27

19.24 ± 0.26

4.5

+++

25.75 ± 3.44

23.70 ± 2.09

PIF 1

8.8

+++

18.95 ± 1.53

19.48 ± 0.20

9.5

+++

23.40 ± 0.93

24.15 ± 0.72

 

18

+++

20.46 ± 3.36

18.99 ± 0.46

19

+++

20.78 ± 2.11

22.61 ± 0.27

 

100

+++

nd

19.25 ± 0.39

103.5

+++

21.33 ± 0.57

23.51 ± 1.73

 

0

- -

- -

- -

0

- -

- -

- -

 

4

+++

nd

22.26 ± 0.42

4.5

+ - +

33.40 ± 4.14

24.53 ± 1.13*

PIF 2

8.8

+++

nd

21.73 ± 0.39

9.5

+++

31.99 ± 5.85

25.31 ± 1.83

 

18

+++

nd

21.22 ± 0.66

19

+++

33.46 ± 1.86

26.44 ± 0.62

 

100

+++

20.27 ± 3.77

21.31 ± 0.53

103.5

+++

32.95 ± 1.19

25.26 ± 2.66

 

0

- -

- -

- -

0

- -

- -

- -

 

0.25

nd

nd

nd

0.25

nd

24.74 ± 0.41*

22.75 ± 0.32*

 

0.375

nd

nd

nd

0.375

nd

27.40 ± 0.45§

21.90 ± 0.02§

PIF 3

4

+++

16.39 ± 0.66

19.69 ± 1.12

4.5

+++

21.72 ± 0.24

24.43 ± 3.03

 

8.8

+++

19.51 ± 2.44

19.40 ± 0.40

9.5

+++

21.80 ± 1.61

22.16 ± 1.22

 

18

+++

18.73 ± 0.49

19.42 ± 0.57

19

+++

21.59 ± 0.96

22.12 ± 1.03

 

100

+++

18.89 ± 0.32

19.29 ± 1.80

103.5

+++

20.67 ± 0.41

21.71 ± 0.46

  1. C T values are means ± standard deviation for 3 independent experiments. +: detection of E. sakazakii; -: no detection of E. sakazakii; nd: not done; *C T value of 2 out 3 independent experiments analysed in duplicate; §C T value of 1 out 2 experiment analysed in duplicate.