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Table 3 Decimal reduction times (D- values), and level of confidence (n = number of decimal logarithm reduction) for the period of application of every disinfecting solution and bacteria tested. The exposure time for n = 6 reduction for every chemical agent and bacteria. The table is organized (3.1 –3.7) based on the chemical agent

From: Chemical resistance of the gram-negative bacteria to different sanitizers in a water purification system

3.1

   

CITRIC ACID (pH 2.4)(0.5%, 30 min)

1D-value [minutes]

2n = 6 log10 [minutes]

3n = t/D

Microorganism

   

A. lowffi

1.77

10.62

16.96

F. aureum

15.77

94.64

1.90

P. aeruginosa

3.81

22.84

7.88

P. alcaligenes

2.99

17.96

10.02

P. diminuta

5.43

32.61

5.52

P. fluorescens

17.06

102.39

1.76

P. picketti

3.29

19.76

9.11

B. subtilis ATCC 9372

9.51

57.09

3.15

E. coli ATCC 25922

7.73

46.37

3.88

P. aeruginosa ATCC 15442

8.95

53.72

3.35

P. alcaligenes INCQS

4.54

27.22

6.61

P. diminuta ATCC 11568

9.50

56.98

3.16

P. fluorescences ATCC 3178

5.32

31.91

5.64

P. picketti ATCC 5031

4.35

26.08

6.90

3.2

   

HYDROCHLORIC ACID (pH 0.3)(5.0%, 30 min)

1 D-value [minutes]

2 n = 6 log 10 [minutes]

3 t = n × D

Microorganism

   

A. lowffi

7.26

43.57

4.13

F. aureum

5.67

34.03

5.29

P. aeruginosa

6.88

41.29

4.36

P. alcaligenes

5.56

33.39

5.39

P. diminuta

6.49

38.91

4.63

P. fluorescens

9.12

54.74

3.29

P. picketti

10.81

64.86

2.78

B. subtilis ATCC 9372

10.88

65.29

2.76

E. coli ATCC 25922

3.70

22.19

8.11

P. aeruginosa ATCC 15442

6.35

38.12

4.72

P. alcaligenes INCQS

4.03

24.16

7.45

P. diminuta ATCC 11568

2.81

16.87

10.67

P. fluorescences ATCC 3178

4.22

25.34

7.10

P. picketti ATCC 5031

4.78

28.71

6.27

3.3

   

ETHYL ALCOHOL (pH 7.2)(70.0%, 1 min)

1 D-value [minutes]

2 n = 6 log 10 [minutes]

3 t = n × D

Microorganism

   

A. lowffi

6.84

41.07

6.84

F. aureum

6.05

36.30

6.05

P. aeruginosa

9.71

58.25

9.71

P. alcaligenes

5.92

35.50

5.92

P. diminuta

5.56

33.39

5.56

P. fluorescens

6.79

40.73

6.79

P. picketti

7.04

42.25

7.04

B. subtilis ATCC 9372

9.98

59.88

9.98

E. coli ATCC 25922

4.49

26.93

4.49

P. aeruginosa ATCC 15442

4.92

29.53

4.92

P. alcaligenes INCQS

8.64

51.81

8.64

P. diminuta ATCC 11568

4.59

27.55

4.59

P. fluorescences ATCC 3178

2.74

16.47

2.74

P. picketti ATCC 5031

5.03

30.15

5.03

3.4

   

SODIUM BISULPHITE (pH 4.0)(0.5%, 90 min)

1 D-value [minutes]

2 n = 6 log 10 [minutes]

3 t = n × D

Microorganism

   

A. lowffi

4.82

28.92

18.68

F. aureum

3.70

22.21

24.32

P. aeruginosa

5.25

31.53

17.13

P. alcaligenes

3.50

21.00

25.71

P. diminuta

4.01

24.04

22.46

P. fluorescens

6.33

38.00

14.21

P. picketti

7.86

47.13

11.46

B. subtilis ATCC 9372

9.47

56.82

9.50

E. coli ATCC 25922

6.05

36.30

14.88

P. aeruginosa ATCC 15442

7.34

44.02

12.27

P. alcaligenes INCQS

6.93

41.55

13.00

P. diminuta ATCC 11568

6.72

40.32

13.39

P. fluorescences ATCC 3178

6.12

36.72

14.71

P. picketti ATCC 5031

4.88

29.25

18.46

3.5

   

SODIUM HYDROXIDE (pH 12.8)(0.4%, 30 min)

1 D-value [minutes]

2 n = 6 log 10 [minutes]

3 t = n × D

Microorganism

   

A. lowffi

12.21

73.26

2.46

F. aureum

16.23

97.40

1.85

P. aeruginosa

14.16

84.99

2.12

P. alcaligenes

11.53

69.20

2.60

P. diminuta

18.45

110.70

1.63

P. fluorescens

10.96

65.79

2.74

P. picketti

16.72

100.33

1.79

B. subtilis ATCC 9372

10.96

65.79

2.74

E. coli ATCC 25922

5.16

30.94

5.82

P. aeruginosa ATCC 15442

5.93

35.57

5.06

P. alcaligenes INCQS

4.28

25.67

7.01

P. diminuta ATCC 11568

5.60

33.59

5.36

P. fluorescences ATCC 3178

4.50

27.00

6.67

P. picketti ATCC 5031

4.22

25.30

7.12

3.6

   

SODIUM HYPOCHLORITE (pH 11.1)(0.5%, 60 min)

1 D-value [minutes]

2 n = 6 log 10 [minutes]

3 t = n × D

Microorganism

   

A. lowffi

5.14

30.85

11.67

F. aureum

3.33

19.99

18.01

P. aeruginosa

7.91

47.43

7.59

P. alcaligenes

8.58

51.50

6.99

P. diminuta

3.98

23.89

15.07

P. fluorescens

7.29

43.76

8.23

P. picketti

5.30

31.80

11.32

B. subtilis ATCC 9372

9.32

55.92

6.44

E. coli ATCC 25922

4.52

27.10

13.28

P. aeruginosa ATCC 15442

4.54

27.21

13.23

P. alcaligenes INCQS

6.54

39.27

9.17

P. diminuta ATCC 11568

6.43

38.56

9.34

P. fluorescences ATCC 3178

6.32

37.93

9.49

P. picketti ATCC 5031

6.36

38.17

9.43

3.7

   

HYDROGEN PEROXIDE + PERACETIC ACID (pH 2.3)(2.2% + 0.45%, 180 min)

1 D-value [minutes]

2 n = 6 log 10 [minutes]

3 t = n × D

Microorganism

   

A. lowffi

4.19

25.15

42.95

F. aureum

4.64

27.82

38.83

P. aeruginosa

5.53

33.19

32.54

P. alcaligenes

4.87

29.23

36.95

P. diminuta

5.39

32.31

33.43

P. fluorescens

4.36

26.14

41.31

P. picketti

5.44

32.63

33.10

B. subtilis ATCC 9372

7.44

44.64

24.19

E. coli ATCC 25922

4.12

24.73

43.67

P. aeruginosa ATCC 15442

3.78

22.66

47.66

P. alcaligenes INCQS

6.61

39.66

27.23

P. diminuta ATCC 11568

5.39

32.31

33.43

P. fluorescences ATCC 3178

3.41

20.47

52.76

P. picketti ATCC 5031

2.86

17.17

62.91

  1. 1D-value = decimal reduction time; (-1/D) = slope.
  2. 2 t = n × D and n = 6 log10;
  3. t = the exposure time for a 6 log10 reduction in the bioburden (No) with a defined D-value
  4. 3t = n × D, where: t = total exposure time currently used (min); D = D-value determined (min)
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