Improvement of Salmonella Detection on Motility

8/10/2019 Improvement of Salmonella Detection on Motility

1/13

ELSEVI:ER

International Journal of

Food Microbiology 27 (1995) 147-159

htem ti n l Journal

ofFoodMicn&&igy

Improvement of Salmonella detection on motility

enrichment media by ferrioxamine E-supplementation of

pre-enrichment culture

Peter Pless a, Rolf Reissbrodt b,*

a

Fachabteilung

ir

das Veteri ni ir w~en beim Amt der Steiermi rk ischen Landesregierung,

Zimmerpl atzgasse S, 8011 Graz, Austr ia

b Robert Koch-lnstitu t, Bereich Wemigerode, BurgstraJ?e 7, D-38855 Wemigerode, Germany

Received 18 July 1994; accepted 18 November 1994

Abstract

Supplementation of buffered peptone water with ferrioxamine E in concentrations

ranging from 0.001 to 1.0 pg/ml significantly increased the motility of Salmonella on

MSRV and DIASSALM semi-solid enrichment media. Zone diameters of swarming S.

enterit idis

and S.

typhimur ium

increased more than twofold following use of pre-enrichment

cultures supplemented with 0.01 pg ferrioxamine E/ml. The activity of ferrioxamine E is

similar ;at 37C and 42C. Pre-enrichment of Salmonella in a variety of foods in supple-

mented buffered peptone water, with shaking at 37C for 6 h and motility enrichment at

42C for 16 h, enabled motile

Salmonella

to be detected in 1 day.

KeyworL; s:Ferrioxamine E-pre-enrichment; Salmonella; Motility enrichment

1 Introduction

Rapjid detection of Salmonella in food by motility enrichment on Modified

Semisolid Rappaport-Vassiliadis (MSRV) media is widely recognised as an effec-

tive procedure for identifying contaminated products at low costs (De Smedt et al.,

1986; De Smedt and Bolderdijk, 1987,1989a,b; Van Netten et al., 1991; ODonoghue

and Winn, 1993; Pless et al., 1993; Van der Zee, 1994). Collaborative studies have

shown the method to be superior to conventional culture methods (Perales and

Audicana, 1989; De Smedt and Bolderdijk, 1990; De Zutter et al., 1991.) The

Corresponding author. Tel.: 03943/679 2.58. Fax: 03943/679 207.

0168-160:5/95/ 09.50 0 1995 Elsevier Science B.V. All rights reserved

SSDI 0168-1605(94)00160-X


2/13

48

P. Pl ess, R. Rei ssbrodt Int . J. Food M i crobi ol ogy 27 (1995) 147-159

technique exploits the motility possessed by most SaImoneZZa strains. Semi-solid

media are unsatisfactory for detecting S.

typhi

and S.

paratyphi

A or other

non-motile strains. However, Holbrook et al. (1989) reported that the incidence of

non-motile strains of Salmonella is very low (approximately 0.15%). Successful

application of motility enrichment is dependent on the strength of motility as well

as the number of cells available (at least 60/m] neccessary according to De Smedt

and Bolderdijk, 1987) after pre-enrichment in appropriate media. Buffered pep-

tone water supplemented with ferrioxamines E or G as selective growth factors

exhibited higher sensitivity and shortened incubation time of most Salmonella

serotypes isolated from the albumen of hens eggs (Reissbrodt and Rabsch, 1993).

Ferrioxamine E have been produced biotechnologically and acts in supplying

Salmonella with very well utilizable iron.

This paper reports on effectiveness of the combination of ferrioxamine E-supp-

lemented buffered peptone water and of the modified semi-solid Rappaport-Vas-

siliadis media in isolation and identification of

Salmonella.

2. Material and methods

Bacteria: Salmonella strains used in experiments detailed in Tables l-3 were

taken from the collection of the Nationales Referenzzentrum der Salmonellosen at

the Robert Koch-Institut, Bereich Wernigerode, Germany. Salmonella strains

listed in Tables 4 and 5 were from the collection of the Institut fiir Fleischhygiene,

Fleischtechnologie und Lebensmittelkunde, Veterinarrnedizinische Universitat

Wien, Austria, and identified by the Gsterreichisches Bundesinstitut fur Bakteri-

ologie und Serologie, Graz, Austria. Each strain was cultured overnight on

Nutrient agar (DIFCO, code no. 0001) incubated at 37C and its identity checked

serologically before use. The most probable number (MPN) technique was used to

determine the number of Salmonella cells inoculated. A plate-drop technique on

XLD-medium (Oxoid CM 469) using the spatula-method according to Baumgart

(1993) was used to determine the numbers of Salmonella for spiking the foods. The

S. enteritidis cells for spiking milk powder were sublethally injured by drying at

43C in condensed milk as described by Edel and Kampelmacher (1973).

2.1. Nutrient media

Buffered peptone water (BPW, Oxoid CM 509) and Modified semi-solid Rappa-

port-Vassiliadis medium (MSRV, Oxoid CM 910) were purchased from Unipath

Ltd., Basingstoke, England. Diagnostic semi-solid salmonella agar (DIASSALM

LAB 537) was kindly provided by LAB M, Topley House, Bury, England. The

media were processed as instructed by the manufacturers and novobiocin to

increase the selectivity added to MSRV and DIASSALM at a concentration of 20

mg/l. A modified Rappaport-Vassiliadis broth according to Pless et al. (1994) was

used in the impedance method. Ferrioxamine E, kindly provided by Dr. H.H.


3/13

Table 1

P. Pl ess,R. Rekbr odt /I nt . J. Food M i crobiol ogy 7 (19%) 147-159

149

Effectiveness of ferrioxamine E-supplementation of Buffered peptone water on swarming behaviour of

Salmonella trains on DIASSALM and MSRV medium, incubated at 37C for 16 h

Ferriox- DIASSALM MSRV

mine E S. enterit idis

(kg/m) 327/94

S. ty phimuri um S. enterit idi s S. t yphimurium

104/94 327/94 104/94

diameter mean/ diameter

mean/

diameter mean/ diameter mean/

(mm)

SD

(mm)

SD

(mm)

SD

(mm)

SD

0 000

O.cQl

0.010

0.100

1.000

2.000

56

50

50

48

54

70

60

70

68

62

70

73

60

69

68

45

30

37

42

36

60

65

60

62

63

50

45

40

50

40

51.60

3.29

66.00

4.69

68.00

4.85

38.00

5.79

62.00

2.12

45.00

5.00

28

35

40

36

32

45

33

40

42

37

40

35

45

42

38

35

22

24

30

24

45

35

37

41

37

35

25

17

21

29

34.20

4.49

39.40

4.62

40.00

3.81

27.00

5.39

39.00

4.00

25.40

6.99

35

30

10

20

30

60

72

43

63

52

60

70

70

67

65

60

60

70

65

61

70

65

65

64

69

65

60

60

59

63

25.00

10.00

58.00

11.02

66.40

4.16

63.20

4.32

66.60

2.70

61.40

2.51

n.d.

25

25

27

29

35

32

43

39

34

30

35

30

34

30

35

27

35

34

30

33

35

38

39

31

25

32

20

24

27

26.50

1.91

36.60

4.39

31.80

2.49

32.20

3.56

35.20

3.35

25.60

4.39

Peters, Ciba-Geigy, Switzerland, was added to buffered peptone water after

sterilization.

2.2. Evaluation

of the eff ectiveness of ferr ioxamine E-supplementation of BPW on the

swarming behaviour of Salmonella subcultur ed to MSRV and DI ASSALM

Two to five cells of each of the

Salmonella

strains were added to 10 ml of fresh

blendecl albumen and stored at room temperature for 16-18 h. One part of each


4/13

150

P. Pl ess, R. Rei ssbrodt / Int . 1. Food M i crobi ol ogy 27 (1995) 147-159

Table 2

Effectivness of ferrioxamine E-supplementation of Buffered peptone water on swarming behaviour of

S. ent eri t i di s 327/94 on DIASSALM and MSRV medium, incubated at 37C for 18 h

Ferrioxmine E

Gg/mi)

0.000

0.010

DIASSALM

diameter (mm)

50

45

45

45

50

45

75

90

85

85

90

mean/SD

46.67

2.58

85.00

6.12

MSRV

diameter (mm)

40

30

30

22

32

25

70

80

90

100

n.d.

mean/SD

29.83

6.21

85.00

12.91

mixture was then added to 10 parts of Buffered peptone water supplemented with

O-2 pg ferrioxamine E/ml and shaken for 6 h at 37C. 50 ~1 drops of each

enrichment culture were inoculated onto the surface of either MSRV or DIAS-

SALM plates and incubated at 37C or 42 C for 16-18 h. The size of zones were

read from five plates of each of the trial groups.

Table 3

Effectiveness of ferrioxamine E-supplementation of Buffered peptone water on swarming behaviour of

S.

enteritidis 327/94

and S.

typhimurium 1@4/94

on MSRV-plates, incubated at 37C and 42C for 18 h

Ferriox- 37C

42C

3PC 42C

mine E

S. enterit idis

(p g/m1) 327/94

S. typhim urium

104/94

diameter mean/ diameter mean/ diameter mean/ diameter mean/

(mm)

SD

mm)

SD

mm)

SD

(mm)

Sd

o.ooo 31 n.d. 17 15

35 20 17 18

30 17 15 16

32 32.20 19 18.00 17 16.40 17 16.40

33 1.92 16 1.83 16 0.89 16 1.14

0.010 62 28 31 26

62 34 33 29

60 34 32 27

60 61.00 34 32.50 35 33.00 29 27.40

61 1.00 n.d. 3.00 34 1.58 26 1.52

1.000 60 44 20 35

55 54 24 34

56 40 22 32

57 57.20 40 44.40 26 22.40 33 33.40

58 1.92 44 5.73 20 2.61 33 1.14


5/13

P. Pl ess, R. Reissbrod /ht . J. Food M icrobi ol ogy 27 (1995) 147-159

151

2.3. Eval uat i on of t he effect of ferr i oxami ne E-supplement at i on of BPW on the

sw armi ng behavi our of Salmonel l a st rai ns isolat ed on MSRVfrom art i fi ci all y i nfect ed

food

Whole eggs, egg yolk and egg white were spiked with different amounts of

Salmonlella cells of various serotypes and origins (Table 3). The spiked samples

were mixed in a ratio of 1:lO with BPW without and with ferrioxamine E-supple-

mentation (1.0 pg/ml) and incubated at 37C for 3, 5 and 8 h. After 3 and 5 h,

samples were taken and stored at 2C in a refrigerator. Three drops (ca. 0.1 ml) of

each of the pre-enrichment cultures were inoculated in separate spots on the

surface of MSRV plates. The MSRV plates were incubated at 42C for 21,lS or 15

h, respectively, and the zones of swarming estimated following the same method

for testing contaminated milk powder, chicken wings and potato chips (Table 4).

Additionally, the impedance changes in the BacTrac 4100 measuring system

(Bacteria Tracer, SY-Lab,3002 Purkersdorf-Vienna, Austria) were measured ac-

cording to Pless et al. (1994). 0.1 ml of the pre-enrichment culture after 3, 5 and 8

h were diluted with 9.9 ml of a modified Rappaport-Vassiliadis broth and incu-

bated at 40C for 22 h. Impedance output higher than 5% of the basic level in

hours was monitored as positive of Salmonella.

2.4. Preli mi nary Salmonel l a t est n t he sw arm zones

The C&esterase reaction was performed according to Olsson et al. (1991). 10 ~1

of MUCAP-reagent (4-Methylumbelliferylcaprylate, kindly provided by Biolife,

Milano, Italy) were droped on the zone of swarming. A bright fluorescent spot on

MSRV and DIASSALM media exposed to 365 nm wavelength UV light for 3-5

min denoted the presence of migrating Salmonella.

3. Results

The swarming behaviour of Salmonella strains on MSRV and DIASSALM

plates was significantly improved after enrichment in Buffered peptone water,

supplemented with ferrioxamine E (Table 1). Few Salmonella cells, injured by

storage in albumen at room temperature overnight (2-5 cells/l0 ml albumen),

multiplied within 6 h to the number necessary for detection if inoculated directly

on the motility enrichment media.

Swarming zones of S. enteritidis 327/94 on MSRV plates were greater than

twofold1 larger when the Buffered peptone water pre-enrichment cultures were

supplemented with 0.001 to 1.0 pg/ml ferrioxamine E than zones formed follow-

ing pre-enrichment in unsupplemented Buffered peptone water ( Tables 1 and 3).

Increasing amounts of ferrioxamine E up to 2 pg/ml BPW did not further

increase zone sizes. A similar effect was seen on DIASSALM plates (Table 1).

However, DIASSALM exhibited bigger swarming zones than MSRV even if


6/13

T

e

4

3

I

n

u

o

e

o

m

n

E

o

h

s

w

m

z

s

z

o

M

R

o

S

Z

m

a

s

p

p

e

e

c

f

o

m

c

a

m

n

e

e

$

S

m

a

s

p

u

T

m

o

2

D

a

m

e

o

s

w

m

z

o

M

R

p

a

e

a

e

p

e

e

c

m

.

9

s

o

y

o

g

n

p

e

e

c

?

s

p

k

w

e

e

m

h

e

y

k

e

w

e

B

w

h

w

h

e

o

w

h

e

o

w

h

e

o

w

h

e

o

w

h

e

o

w

h

e

o

c

C

d

S

2

m

a

m

n

E

a

m

n

E

a

m

n

E

a

m

n

E

a

m

n

E

a

m

n

E

8

B

W

c

B

S

e

e

d

s

e

6

3

n

3

2

0

2

n

3

i

5

1

1

1

3

2

2

0

8

3

3

3

2

2

1

%

3

b

3

0

0

n

3

0

n

2

g

5

2

0

3

2

3

n

3

2

6

3

3

2

3

2

3

0

B

5

3

2

3

2

3

1

j

8

3

3

3

2

3

2

h

3

2

2

3

3

(

1

0

0

2

2

2

;

5

3

3

3

3

1

1

1

3

S

e

n

e

d

s

2

Y

w

3

3

n

3

0

0

1

n

2

0

0

5

1

1

0

2

1

2

2

2

0

;

n

8

3

2

3

2

2

2

1

2

3

n

2

0

0

1

n

1

0

0

\

o

5

2

0

3

1

2

1

1

n

2

2

0

2

3

2

1

3

2

3

0

5

2

1

3

3

1

1

0

3

3

3

8

3

2

3

3

3

2

3

3

2

2

2

2

0

5

3

2

3

3

3

0


7/13

S

y

m

u

e

h

4

3

1

0

2

1

1

*

z

2

1

1

i

U

1

1

1

3

2

2

0

8

3

2

2

3

3

3

1

3

3

3

3

1

0

0

2

1

1

n

1

1

1

5

2

1

3

2

2

4

3

2

2

3

2

2

5

3

2

2

2

0

;

2

3

3

3

3

8

3

3

2

2

e

3

2

2

3

2

2

b

.

J

5

3

3

1

1

;

3

%

a

s

T

e

5

E P 8

\

g h 8 E


8/13

T

e

5

I

n

u

o

e

o

m

n

E

o

h

s

w

m

n

z

o

M

R

o

S

m

a

s

p

a

o

h

m

o

p

f

o

o

w

n

p

e

e

c

m

c

u

e

f

o

m

c

a

m

n

e

m

k

n

w

c

c

w

n

a

n

a

o

c

n

S

m

o

a

s

p

u

T

m

o

D

a

m

e

o

s

w

m

z

a

e

O

p

o

m

a

e

f

o

s

o

y

o

g

n

s

p

k

w

h

c

s

p

e

e

c

m

h

p

e

e

c

m

w

h

f

e

o

w

h

e

o

p

e

e

cm

(

h

w

h

f

e

o

w

h

e

o

M

k

l

O

a

m

n

E

a

m

n

E

a

m

n

E

a

m

n

E

S

e

e

S

e

h

y

7

3

n

n

p

w

t

d

L

%

i

n

u

e

5 8 3

b

s

g

7

3 5 8 3

5

7

3 5 8 3 5

n

d

n

d

C

c

S

e

e

U

w

7

w

n

t

d

s

3 5

8

3 5

2 3

2 2 n 3

2 2

2 2

2

3 2

1

2 3

2 2 2 2

2 3 2

1 1 1

3

3 3 3 3

3

3 3

3 2

2

1

2 3

3 3 0 3

3

3 3

3

2

2

1

2 3

3 3 0 3

2 2 3 3 2

2

1

0 2

n

d

1

6

1

6

1

0

n

d

1

7

1

6

2

1

1

6

5

6

n

d

Y

1

8

2

7

1

;

8

*

P ;

1

5

%

9

8

\

o

4

0

n

d

n

d

1

5

1

5

1

0

1

2


9/13

C

c

S

e

t

e

w

n

t

d

i

s

7

3

3

3

2

3

3

2

n

d

1

2

P

a

o

c

p

s

u

s

l

a

w

P

5

2

2

2

3

3

2

1

2

1

5

8

2

2

1

3

2

2

1

2

1

9

3

3

3

1

3

3

2

-

5

3

3

3

N

u

a

y

3

2

2

2

2

2

2

n

d

n

d

c

a

m

i

n

e

5

3

2

2

3

3

2

1

n

d

2

4

c

n

d

8

3

2

2

3

2

2

7

3

7

0

c

n

d

3

2

2

2

2

1

1

-

5

3

2

2

3

3

2

1

-

c

n

d

a

D

e

y

d

o

o

o

M

R

p

a

e

a

e

t

h

p

e

e

c

m

t

m

n

c

e

b

D

e

y

d

o

o

o

M

R

p

a

e

a

e

h

p

e

e

c

m

t

m

n

c

e

a

o

y

a

m

o

s

o

a

a

2

C

o

h

s

m

n

a

e

p

e

e

c

m

u

h

w

k

n

d

w

n

s

h

T

s

m

3

o

5

h

o

s

o

a

a

2

C

e

p

v

y

n

e

b

D

a

m

e

o

s

w

m

z

n

=

a

h

e

d

o

d

d

n

s

w

m

0

=

o

d

o

d

d

n

s

w

m

=

w

m

z

u

o

1

cm

2

=

s

w

m

z

l

2

c

m

3

=

s

w

m

z

2

3

c

m

=

o

w

m

t

h

w

e

M

R

p

a

e

4

c

n

=

c

m

o

n

S

m

a

n

d

=

n

d

e

e

(

n

o

p

>

5

%

a

e

2

h


10/13

56

P. Pl ess, R. Reissbrodt /ht . J. Food M i crobi ol ogy 27 (199.5) 147-159

ferrioxamine E was not present. For S. enteritidis 327/94, supplementation of the

Buffered peptone water pre-enrichment culture with 0.01 pg/ml ferrioxamine E

enabled zone sizes on MSRV to develop to a size similar to those on DIASSALM

(Table 2). A decrease in zone size diameters occurred at ferrioxamine E concentra-

tions of 0.1 pg/ml and 2.0 pgg/ml. Diameters of swarming zones differed depen-

dent from preparation of the plates and of incubation time. However, ferrioxamine

E promoted the swarm behaviour of Salmonella as demonstrated in all the

experiments.

S. fyphimurium 104/94 showed smaller improvements of swarming behaviour

but also exhibited significantly larger swarm zones when supplemented with

ferrioxamine E.

The diameter of swarm zones is dependent on the incubation temperature of

the motility enrichment media (Table 3). The swarming zones of S, enteritidis

327/94 were significantly smaller in size when incubated at 42C compared to 37C

and behaved similarly to those of S. typhimurium 104/94. However, the swarming

behaviour of both the strains tested was promoted by ferrioxamine E-supplementa-

tion of BPW, at both 37C and 42C zones on MSRV were twice as large as those

resulting from unsupplemented BPW.

Whole egg, egg yolk and egg white were contaminated with different cell counts

of two S. enterit idk strains and one S. typhimurium strain, isolated from eggs.

Detection of swarming zones and their diameters on MSRV were significantly

improved by supplementation of Buffered peptone water with 1 pg/ml ferrioxam-

ine E. Swarm zones could be seen after 3 or 5 h incubation in ferrioxamine

E-supplemented BPW seeded with 25-60 cells per 200 ml (Table 4). Contrarily, no

swarm zones were detected on MSRV inoculated with cultures of egg white in

BPW not containing ferrioxamine E after 3 h. The diameters of swarm zones in all

experiments conducted were enlarged by use of ferrioxamine E-supplemented

BPW. This principle was retained when more cells were inoculated and when

incubation time was increased to 8 h. Storage of the culture samples at 2C for 3 or

5 h did not significantly influence the swarming behaviour of the Salmonella strains

tested. Formation of swarm zones on MSRV and increase in their diameter

effected by ferrioxamine E-supplementation was most noticeable for egg white and

whole eggs. Larger zones were produced by egg yolk and ferrioxamine E-supple-

mentation did cause any increase in diameter.

Similar results were obtained from contaminated milk powder, chicken wings,

and potato chips, respectively (Table 5). Low numbers (ca. 7 cells/ml) of sub-

lethally injured S. enter-Z&s cells in milk powder after 5 h pre-enrichment in BPW

with ferrioxamine E produced swarm zones on MSRV of 2-3 cm. Using higher cell

counts no significant differences could be detected of pre-enrichment with and

without ferrioxamine E. Impedance changes denoting cell multiplication could be

detected significantly earlier after cultivation in ferrioxamine E-supplemented

BPW (Table 5). Swarming behaviour and impedance changes were the same when

pre-enriching without and with ferrioxamine E from chicken wings and potato

chips as they were for isolates from milk powder.


11/13

P. Pless, R. Rehsbrodt ht. J. Food M icrobiology 27 1995) 147-159

157

4 Discussion

The composition of motility enrichment media for Salmonella as well as the

temperature of incubation (at 42C, most of the competitors like E. cloaca or C.

&versus cannot swarm), pH of the medium and addition of iron and sulphite salts

were intensively studied and resulted in the present formulas of MSRV (Oxoid) or

DIASSALM (Lab M). For one-day detection of Salmonella by motility enrichment

a very effective pre-enrichment medium is needed. The use of M-broth described

by Sperber and Deibel (1969) has been reviewed by De Smedt and Bolderdijk

(1989b). Ferrioxamine E-supplementation of Buffered peptone water functions in

shortening the incubation time and increasing the sensitivity of pre-enrichment

culture of injured Salmonella [(Reissbrodt and Rabsch (1993)l. This supplementa-

tion is also very effective in improving the swarming behaviour of Salmonella

strains on MSRV and DIASSALM semi-solid motility enrichment media (Table 1).

As little as l-10 ng ferrioxamine E/ml BPW is necessary to increase the diameter

of swarming zones on MSRV greater than twofold in contrast to Salmonella cells

grown in BPW without supplementation. The diameters of swarm zones on

DIASSALM are larger than those on MSRV ( Tables 1 and 2) after inoculation of

pre-enrichments that are not supplemented with ferrioxamine E. Pre-enrichment

of Salmonella enteritidis 327/94 in ferrioxamine E-supplemented BPW compen-

sated for this advantage (Table 2). The effectiveness of ferrioxamine E-supplemen-

tation is detectable when incubating MSRV media at either 37C or 42C (Table

3).

Improved swarming of Salmonella on motility enrichment media was detected

over the range 0.001 to 1,0 pg ferrioxamine E/ml BPW. Addition of ferrioxamine

E to the motility enrichment media as well as 30 min incubation of the diluted cells

before inoculation applicated onto the surface of MSRV or DIASSALM plates

had no effect (data not shown). No effect was seen also after supplementation of

the modified Rappaport-Vassiliadis broth for impedance measurements.

It is assumed that repair of the injured cells and availability of a portion of

viable cells amongst the high number produced during pre-enrichment are the

reasons of this effect. Investigations into the influence of ferrioxamine E on the

flagella-apparatus are in progress.

Ferrioxamine E is not able to feed E. coli or the Proteus-frouidencia-

Morganella-group. This confers a selective advantage on Salmonella in motility

enrichment. The efficacy of pre-enrichment culture in BPW supplemented with

ferrioxamine E for recovery of different numbers of various Salmonella spp.

contai.ned in a variety of artificially contaminated foods is shown in Tables 4 and 5.

Salmonella could be detected on MSRV after enrichment for 3 h in 200 ml of

ferrioxamine E-supplemeted BPW. Detection of Salmonella by motility enrich-

ment seems to be not influenced by storage the pre-enrichment samples at 2C for

5 or 3 h. The period of enrichment required for detection is dependent on the

number of Salmonella present in the food. The diameters of swarming zones were

larger than those from unsupplemented BPW.

Impedance changes were detected earlier by BacTrac 4100 when samples were

enriched in ferrioxamine E-supplemented BPW.


12/13

158 P. PIem, R. Reissbrodt /ht. J. Food M icr obiology 27 fl 995) 147-159

Various techniques can be used to identify

Salmonella

from swarm zones. A

slide agglutination test performed using a loopful of the migrating cells at the zone

edge and also direct inoculation on selective nutrient media followed by biochemi-

cal confirmation have been described (De Smedt et al., 1986). Pless et al. (1993)

reported on the successful use of a latex agglutination test. The present studies

have shown that the C8-esterase reaction employed in the MUCAP-reagent may

be used with both MSRV and DIASSALM media. These media appear to be as

appropriate for this test similar as McConkey agar, reported as the best medium by

Olsson et al. (1989). Pre-enrichment in ferrioxamine E-supplemented Buffered

peptone water for 6 h, preferably with shaking or stirring, followed by motility

enrichment on MSRV or DIASSALM medium for 16-24 h improved detection of

motile Salmonella spp. also of sublethally injured cells. MUCAP-reagent is used

to confirm that swarming growth on the semi-solid medium is Salmonella. Serolog-

ical testing is performed to establish the identity of motile serovars.

Further investigations are needed, aimed at determining the suitability of the

method for a wider range of serovars and sub-species. More work is also needed to

confirm the efficacy of ferrioxamine-E supplementation for detecting Salmonella

in mixed bacterial populations, not only by conventional culture methodology, but

also by other methods including rapid test systems.

Acknowledgements

David E. Post, Unipath Ltd., England, is gratefully acknowledged in recognition

of critical reading of the manuscript. The technical assistance of Barbel Burghardt

was greatly appreciated.

References

Baumgart, J. (1993) Mikrobiologische Untersuchungen von Lebensmitteln. Behrs Verlag Hamburg, pp.

77-84

De Smedt, J.M., Bolderdijk, R.F., Rappold, H. and Lautenschhiger, D. (1986) Rapid Salmonella

detection in foods by motility enrichment on a modified semi-solid Rappaport-Vassiliadis medium.

J. Food Prot. 49,510-514.

De Smedt, J.M. and Bolderdijk, R.F. (1987) Dynamics of Salmonella isolation with modified semi-solid

Rappaport-Vassiliadis medium. J. Food Prot. 50, 658-661.

De Smedt, J.M. and Bolderdijk, R.F. (1989 a) One day detection of Salmonella from foods and

environmental samples by motility enrichment. In: A. Balows, R.C. Tilton and A. Turano (editors),

Rapid Methods and Automation in Microbiology and Immunology. Brixia Academic Press, Brescia,

pp. 728-732.

De Smedt, J.M. and Bolderdijk, R.F. (1989bJ One day detection of Salmonella by motility enrichment

on modified semi-solid Rappaport-Vassiliadis medium. In: Modem Microbiological Methods For

Dairy Products. Proceedings of a seminar organized by the Comitt National Lechero. Menendez

Pelayo International University, Santander, Spain, pp. 410-413.

De Smedt, J.M. and Bolderdijk, R.F. (1990) Collaborative study of the international office of cocoa,

chocolate, and surgar confectionery on the use of motility enrichment for

Salmonella

detection in

cocoa and chocolate. J. Food Prot. 53,659-664.


13/13

P. Pl ess, R. Reissbrodt ht . J. Food M i crobi ol ogy 27 (1995) 147-159

159

De Zutter, L., De Smedt, J.M., Abrams, R., Beckers, H., Catteau, M., de Borchgrave, J., Debevere, J.

Hoekstra, J., Jonkers, F., Lenges, J., Notermans, S., van Damme, L., Vandermeersch, R., Ver-

braeken, R. and Waes, G. (1991) Collaborative study on the use of motility enrichment on modified

semisolid Rappaport-Vassiliadis medium for the detection of Salmonella from foods. Int. J. Food

Microbial. 13, 11-20.

Edel, W. and Kampelmacher, F.H. (1973) Comparative studies on the isolation of sublethally injured

Salmonella i n ni ne European l aborat ori es, Bull. WHO 48, 167-174.

Holbrook, R., Anderson, J.M., Baird-Parker, AC., Dodds, L.M., Sawhney, A., Stuchbury, S.H. and

Swaine, D. (1989) Rapid detection of Salmonella in foods -a convenient two-day procedure. Lett.

Appl. Microbial. 8, 139-142.

Netten, .P. van, van der Zee, H. and van de Moosdijk, A. (1991) The use of a diagnostic semi-solid

medium for the isolation of

Salmonella enteritidis

from poultry. Quality of poultry products. III.

Safety and marketing aspects. Spelderhalt Jubilee Symposia, Doorwerth.

ODonoghue, D. and Winn, E. (1993) Comparison of the MSRV method with an in-house conventional

method for the detection of Salmonella in various high and low moisture foods. Lett. Appl.

Microbial. 17, 174-177.

Olsson, M., Syk, A. and Wollin, R. (1991) Identification of

Salmonellue

with the 4-Methylumbelliferyl

Caprilate Fluorescence Test. J. Clin. Microbial. 29, 2631-2632.

Perales, I. and Audicana, A. (1989) Evaluation of semi-solid Rappaport medium for detection of

Salmonellue in meat products. J. Food Prot. 52, 316-319.

Pless, P., Asperger, H., Scheider, M. and Schopf, E. (1993) Erweiterte Einsatzmoglichkeiten eines

modifizierten Beweglichkeitsmediums (MSRV-Medium) fiir den Salmonellennachweis. Arch.

Lebensmittelhyg. 44, 125-127.

Pless, P., Futschik, K. and Schopf, E. (1994) Rapid detection of Salmonella by means of a new

impedance-splitting method. J. Food Prot. 57, 369-376.

Reissbrodt, R. and Rabsch, W. (1993) Selective preenrichment of Salmonella from eggs by siderophore

supplements. Zbl. Bakteriol. 279, 344-353.

Sperber, W.H. and Deibel, R.H (1969) Accelerated procedure for Salmonella detection in dried food

and feeds including only broth cultures and serological reactions. Appl. Microbial. 17, 533-539.

Zee, H. van der (1994) Conventional methods for the detection and isolation of Salmonella etzteritidis.

Int. J. Food Microbial. 21, 41-46.

Date post:	02-Jun-2018
Category:	Documents
Upload:	giuseppegnr
View:	223 times
Download:	0 times

Improvement of Salmonella Detection on Motility

Documents