Table 2: Qualitative persistence of generic E. coli (E) and Salmonella (S) in various Oregon agricultural soils at low (2.0-2.4 log CFU/g) and high (3.3-3.6 log CFU/g) levels of initial contamination.

Low Initial Inoculum

Alifisols

Aridisols

Mollisols

Quatama

Latourell

Adkins

Willamette

Madras

Cullius

day

E

S

day

E

S

day

E

S

day

E

S

day

E

S

day

E

S

26

1/5^a

0/5

26

5/5

0/5

59

0/5

4/5

29

0/5

0/5

44

3/10

1/10

59

3/5

0/5

29

0/5

0/5

29

0/5

0/5

62

0/5

0/5

32

0/5

1/5

51

2/10

2/10

62

0/5

0/5

32

0/5

0/5

32

0/5

0/5

65

0/5

0/5

35

0/5

0/5

58

1/10

1/10

65

0/5

0/5

35

0/10^b

1/10

35

0/10

2/10

68

1/10

8/10

38

0/5

0/5

65

1/10

2/10

68

1/10

1/10

42

0/10

1/10

42

1/10

1/10

75

2/10

8/10

41

0/10

1/10

72

2/10

1/10

75

3/10

3/10

49

0/10

0/10

49

0/10

0/10

82

2/10

10/10

48

0/10

0/10

79

3/10

1/10

82

4/10

1/10

High Initial Inoculum

Alifisols

Aridisols

Mollisols

Quatama

Latourell

Adkins

Willamette

Madras

Cullius

Day

E

S

day

E

S

day

E

S

day

E

S

day

E

S

day

E

S

38

0/5

0/5

53

0/5

0/5

71

0/5

1/5

65

2/5

1/5

62

2/5

1/5

71

2/5

3/5

41

5/10

6/10

56

4/10

9/10

74

2/5

3/5

68

2/5

0/5

65

1/5

0/5

74

1/5

1/5

48

4/10

3/10

63

1/10

3/10

77

2/5

5/5

71

0/5

0/5

68

0/5

0/5

77

2/5

2/5

55

0/10

3/10

70

1/10

3/10

80

3/5

5/5

74

0/5

0/5

71

0/5

0/5

80

1/5

1/5

62

2/10

2/10

78

0/10

2/10

83

4/5

5/5

77

0/10

4/10

74

10/10

4/10

83

2/5

1/5

69

0/10

0/10

84

2/10

2/10

86

3/5

5/5

84

3/10

5/10

81

5/10

8/10

86

5/5

1/5

^aResults with a denominator of 5 indicate samples on respective day were analyzed using Most Probable Number methodology. Numerator indicates number of samples analyzed that were positive for either generic E. coli or Salmonella.

^bResults with a denominator of 10 indicate samples on respective day were analyzed for the qualitative presence or absence of generic E. coli or Salmonella by enrichment methodology.

Numerator indicates the number of samples analyzed that were positive for either generic E. coli or Salmonella.