Table 2 Antimicrobial activity exerted by lyophilized and stored (for 2, 4, and 6 months) L. rhamnosus GG and L. plantarum GP growing on MRS agar against Gram negative and Gram positive bacteria determined by spot overlay assay

E. coli

25 ± 0.3

30 ± 0.4

32 ± 0.7

25 ± 0.9

29 ± 1.4

33 ± 0.7

Ent. aerogenes

19 ± 2.1

27 ± 0

28 ± 0.2

19 ± 0.4

35 ± 2.4

38 ± 0.2

Sal. typhi

16 ± 0.4

24 ± 0.6

21 ± 0.7

25 ± 0.7

33 ± 0.2

33 ± 0.4

Shigella sp.*

25 ± 0.7

30 ± 4.2

31 ± 0.3

36 ± 0.7

27 ± 0.3

27 ± 0.4

Pr. vulgaris*

18 ± 0.2

23 ± 1.4

22 ± 0.0

28 ± 2.1

33 ± 2.1

34 ± 1.1

K. pneumoniae*

22 ± 0.3

26 ± 1.2

31 ± 0.3

27 ± 1.7

22 ± 0.1

2 ± 0.9

Staph. aureus

25 ± 0.4

22 ± 0.8

21 ± 0.6

24 ± 0.4

26 ± 0.4

25 ± 0.6

Sr. marcescens

25 ± 0.6

29 ± 2.1

33 ± 0.2

32 ± 0.2

31 ± 0.2

27 ± 1.6

Ps. aeruginosa

22 ± 0.8

24 ± 1.9

30 ± 0.6

29 ± 1.0

26 ± 0.4

25 ± 0.2

B. cereus

20 ± 0.2

21 ± 0.2

21 ± 0.4

21 ± 0.4

24 ± 1.0

24 ± 1.2

B. megaterium*

19 ± 0.3

26 ± 2.8

32 ± 0.5

33 ± 0.8

34 ± 0.5

29 ± 1.2

B. subtilis

23 ± 0.4

24 ± 0

22 ± 0.6

23 ± 1.0

24 ± 0.6

20 ± 1.2

E. coli

25 ± 0.7

25 ± 0.2

25 ± 0.5

21 ± 0.5

20 ± 0.5

24 ± 0.7

Ent. aerogenes

19 ± 0.7

19 ± 0.1

20 ± 0.0

17 ± 1.1

23 ± 0.5

24 ± 1.2

Sal. typhi

10 ± 0.2

22 ± 1.4

21 ± 0.1

16 ± 4.2

26 ± 1.4

27 ± 0.7

Shigella sp. *

24 ± 0.3

29 ± 0.7

22 ± 1.0

19 ± 0.9

27 ± 2.1

23 ± 2.1

Pr. vulgaris*

15 ± 0.4

21 ± 1.4

19 ± 0.2

17 ± 0.3

25 ± 2.1

18 ± 0.8

K. pneumoniae*

20 ± 0.6

25 ± 1.2

26 ± 0.8

20 ± 1.4

17 ± 0

19 ± 1.0

Staph. aureus

18 ± 0.4

18 ± 0.6

20 ± 0.2

20 ± 0.2

19 ± 0.2

17 ± 0.8

Sr. marcescens

24 ± 0.4

25 ± 0.2

26 ± 0.2

27 ± 0.2

29 ± 0.4

25 ± 1.9

Ps. aeruginosa

18 ± 1.0

20 ± 1.7

27 ± 0.8

25 ± 1.5

23 ± 0.7

23 ± 0.7

B. cereus

14 ± 1.4

16 ± 0.6

16 ± 0.4

16 ± 0.2

15 ± 0.2

17 ± 0.8

B. megaterium*

15 ± 0.4

21 ± 3.1

26 ± 1.0

23 ± 0.4

23 ± 0.4

18 ± 2.5

B. subtilis

15 ± 0.6

18 ± 1.9

21 ± 0.8

15 ± 1.4

13 ± 0.6

14 ± 0.2

E. coli

24 ± 0.4

24 ± 0.1

25 ± 1.4

14 ± 2.1

14 ± 3.5

20 ± 2.8

Ent. aerogenes

14 ± 0.4

16 ± 0.2

15 ± 0.2

14 ± 2.8

18 ± 0.7

18 ± 2.1

Sal. typhi

10 ± 0.4

20 ± 2.1

15 ± 0.3

11 ± 0.1

17 ± 2.8

18 ± 0.8

Shigella sp.*

17 ± 0.6

28 ± 4.2

22 ± 0.2

16 ± 0.4

23 ± 0.2

16 ± 0.6

Pr. vulgaris*

13 ± 0.6

14 ± 2.1

15 ± 1.0

17 ± 4.9

16 ± 1.1

16 ± 2.8

K. pneumoniae*

15 ± 0.8

18 ± 2.1

20 ± 1.0

16 ± 0.8

15 ± 0.4

16 ± 0.2

Staph. aureus

12 ± 0.5

14 ± 1.2

17 ± 0.3

15 ± 0.3

13 ± 0.1

12 ± 0.1

Sr. marcescens

16 ± 0.6

21 ± 1.4

23 ± 0.6

22 ± 0.2

22 ± 0.4

18 ± 1.0

Ps. aeruginosa

15 ± 0.6

17 ± 0.2

20 ± 0.8

19 ± 1.2

18 ± 0.8

17 ± 1.2

B. cereus

12 ± 1.0

11 ± 0.4

11 ± 0.4

11 ± 0.4

13 ± 0.4

15 ± 0.4

B. megaterium*

13 ± 0.6

17 ± 0.8

22 ± 1.2

20 ± 2.1

16 ± 0.6

16 ± 0.6

B. subtilis

13 ± 0.8

17 ± 0.5

19 ± 0.1

15 ± 1.5

11 ± 0

10 ± 0.1