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Material Safety Data Sheet

Required Products

Organisms

Organisms this product works with:

For this Organism

Other products used in the isolation of Salmonellae:

Rapid Food Tests

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SALMONELLA RAPID TEST

CODE:FT0201

The Oxoid Salmonella Rapid Test is for the presumptive detection of motile salmonella in all food materials, finished food products and factory environmental samples.

Principle
Pre-enrichment of a homogenised sample in a suitable medium is followed by inoculation of the culture vessel containing a salmonella elective medium with pre-enriched culture. The culture vessel is equipped with two tubes. Each tube contains a selective medium and an upper indicator medium separated by a porous partition. Salmonella migrate actively through the lower selective medium to the upper indicator media where their presence is indicated by a colour change. The Oxoid Salmonella Rapid Test was reviewed by AOAC Research Institute (USA) and was found to perform according to the specifications mentioned in the pack insert, and the certificate is available (PDF).

Components of the Kit:
FT0201 – 50 culture vessels
Each culture vessel contains 2 tubes :
Tube A (blue cap) contains Modified Rappaport- Vassiliadis medium as a selective medium, and Modified Lysine Iron Cystine Neutral Red Medium as the indicator medium.
Tube B (red cap) contains Modified Lysine Deoxycholate Medium as the selective medium and Modified Brilliant Green Medium as the indicator medium.
50 Novobiocin Discs (FT0207) each containing 1.8mg of novobiocin.
2 syringes and needles
1 spanner (FT0202)
50 labels
1 instruction leaflet

Materials required but not supplied:
Pre-enrichment Medium
Sterile Distilled Water
Salmonella Rapid Test Elective Medium (SRTEM) Code CM0857
Preparation Tray (FT0300)
Pipettes
Salmonella Latex Test (FT0203)
Vortex Mixer
Incubators, 35, 37 and 41ºC

Preparation of the Test Material
Test samples are pre-enriched in a suitable medium for example by homogenisation of a 1:10 dilution of the sample in Buffered Peptone Water (CM0509). Incubate the pre-enrichment culture at 35ºC or 37ºC for 18 hours.

Procedure
Preparation of the culture vessel
Use good microbiological techniques throughout. Each vessel must be prepared to stage six before preparing the next one.
1. Tap the culture vessel at an angle to loosen any medium which may have become compacted in the tubes. Unscrew the lid of the culture vessel.
2. Add sterile distilled water up to the lower line (line 1) marked on the side of the culture vessel (approximately 27 ml). Check that the base of broth tubes A and B is below the level of the liquid.
3. Expose the head of the needle but do not remove the needle from its safety sheath. Attach the head of the needle to the syringe. Remove the safety sheath and carefully push the needle through the central wall in the top of the blue cap (Tube A) ensuring the needle is visible below the cap. Smoothly withdraw the syringe plunger until the liquid level in the tube reaches the line (line 3) marked on the culture vessel. The rate of withdrawal should be such that approximately 5 seconds is taken for the operation. Remove the syringe and needle and replace the safety sheath. Take care that the tube is not lifted from its position in the container and that the tube cap is not loosened.
4. Immediately repeat step 3 for tube B that has the red cap.
5. Replace the culture vessel lid. Press the side of the culture vessel containing the 2 tubes firmly to a vortex mixer and operate the mixer. It is important that the liquids in the tubes are agitated vigorously for approximately 5 seconds. After mixing, leave the container to stand for approximately 5 minutes. The vessel may now be left for up to 4 hours before moving on to stage 6.
6. Carefully remove the lid of the culture vessel. Pour sterile, cooled Salmonella Rapid Test Elective Medium (SRTEM) into the culture vessel container until the liquid level reaches the upper line (line 2) on the culture vessel wall (prepare the medium as directed on the label of the SRTEM container CM0857).
7. Aseptically add 1 Novobiocin disc to the culture vessel.
WARNING: Take care that the culture vessel is maintained in an upright position throughout the remainder of the test.
8.
Use the spanner provided to remove the red and blue caps from the tubes. Avoid touching the tubes themselves or the inner surface of the culture vessel by hand. Discard the red and blue caps.
9. Replace the culture vessel lid. The culture vessel is now ready for use
.Use of the culture vessel
1. The incubated pre-enrichment culture should be shaken and then allowed to stand until the coarse particles have settled. Identify the sample using one of the labels provided and attach the label to the culture vessel.
2. Remove the culture vessel lid and add 1ml of the pre-enrichment culture to the vessel.
3. Replace the lid on the culture vessel.
4. Place the culture vessel in an incubator controlled to 41ºC (± 0.5ºC) and incubate for 24 hours. The culture vessel must be kept in an upright position at all times.

Reading and Interpretation
1.
After 24 hours incubation, remove the culture vessel from the incubator and in good light examine the upper indicator sections of the tubes for colour changes. Examine the tubes through the container wall. Do not remove the tubes from the container!
Blackening may occur in the lower sections of the tubes. Colour reactions should be noted in the upper indicator sections only.

2. The possible presence of salmonella is shown by changes in colour of the upper indicator medium in either one or both of the tubes.
POSITIVE:
Tube A – ANY DEGREE OF BLACK COLOURATION
Tube B – ANY DEGREE OF RED OR BLACK COLOURATION
NEGATIVE:
Tube A – ABSENCE OF BLACK COLOURATION
Tube B – ABSENCE OF RED OR BLACK COLOURATION
Tube A
Colour reactions of the indicator media in the upper compartments:
(1) Prepared unit before incubation
(2) Negative result – no blackening
(3) Positive result – some blackening
(4) Positive result – Strong blackening
Tube B
Colour reactions of the indicator media in the upper compartments:
(1) Prepared unit before incubation
(2) Negative result – little change
(3) Negative result – yellow, green top
(4) Negative result – yellow, green top
(5) Positive result – reddening only. Reddening may be limited to a very narrow band at the meniscus.
(6) Positive result – weak reddening and blackening.
(7) Positive result – red and black
(8) Positive result – red and black
NOTE: THESE COLOUR DESCRIPTIONS ARE INTENDED AS GENERAL GUIDE ONLY. IF WEAKER POSITIVE REACTIONS ARE SEEN, THE CULTURES SHOULD BE TESTED WITH THE SAMONELLA LATEX TEST.

3. Tubes which show positive reactions must be tested further with the Oxoid Salmonella Latex Test (Code FT0203). Those giving positive results with the Salmonella Latex Test may be reported as presumptively containing Salmonella. Results should then be confirmed using traditional culture and serological techniques by subculturing through a selective enrichment from the upper indicator compartment in the tube giving a positive latex test result.

Limitations
The detection method used in this test is not appropriate for the detection of non-motile strains of Salmonella (incidence <0.1%). Salmonella growth in this system may be inhibited at or above 43ºC. The system is designed to be compatible with the Oxoid Salmonella Latex Test (FT0203). It has not been validated with other serological confirmation tests.

Precautions
Good microbiological techniques must be used at all times.
Do not pipette by mouth.
Autoclave all used culture vessels before disposal.
It is recommended that at the start of each new batch of tests the syringe and needle should be decontaminated by flushing through the 70% ethyl alcohol at least twice. Expel any residual alcohol from the syringe and needle before use. When not in use store the syringe and needle in a closed container.

Storage Conditions
Store the kit at 18-25ºC in a dry place.
Once the full pouches containing the culture vessels are opened, any unused culture vessel should be kept with the silica gel pack in the resealed foil pouches.
All kit components should be used before the expiry date shown on the box.

Performance Characteristics
The Oxoid Salmonella Rapid Test was compared against traditional culture techniques in a variety of foods. The study involved over 800 samples assessed at nine independent food laboratories throughout Europe and in the United States .
The trial laboratories were asked to use the Oxoid Salmonella Rapid Test in parallel with their traditional culture technique.

Food Product

No. Samples

Total
Positive‡Sample

No. Positive Results

Oxoid

Traditional

Poultry

116

(10)†

48

(8)

47

(7)

43

(8)

Raw Meats

236

(45)

87

(34)

87

(34)

76

(30)

Cooked Meats

23

(6)

6

(6)

6

(6)

6

(6)

Offal

10

 

6

 

5

 

3

 

Vegetables

25

(1)

1

(1)

1

(1)

1

(1)

Pastry Products

35

(24)

18

(18)

18

(18)

18

(18)

Herbs and Spices

38

(15)

15

(15)

15

(15)

15

(15)

Whey

9

 

1

 

1

 

1

 

Milk Powders

28

(10)

10

(10)

10

(10)

10

(10)

Ice Cream

19

(6)

6

(6)

6

(6)

6

(6)

Egg/Milk Mix

21

 

2

 

2

 

2

 

Environmental Swabs

37

 

2

 

1

 

2

 

Animal Feeds

100

 

8

 

7

 

5

 

Others

 

 

 

 

 

 

 

 

TOTAL

820

(117)

223

(98)

216

(97)

201

(94)

Traditional method sensitivity: 201/223 = 90.13%
Oxoid sensitivity: 216/223 = 96.8%
Samples positive by traditional methods, or Oxoid with confirmation or both
† The figures in brackets represent artificially inoculated samples.

References
1.
Compendium of Methods for the Microbiological Examination of Foods 2 nd Ed. (1984), American Public Health Association Inc., Ed. M. L. Speck.
2. F.D.A. Bacteriological Analytical Manual, 6 th Ed. (1984). Published by Association Official Analytical Chemists.
3. Microorganisms in Food 1, (1978), 2 nd Ed., International Commission on Microbiological Specifications for Foods. University of Toronto Press.
4. Personal Communication from Dr. A.C. Baird-Parker.
5. Rapid Detection of Salmonellae in Foods – A convenient two day Procedure. Letters in Applied Microbiol., 1989, 8, 139-142. R. Holbrook, J.M. Anderson, A.C. Baird-Parker, L.M. Dodds, D. Sawhney, S.H. Stuchbury and D. Swaine.
6. Comparative Evaluation of the Oxoid Salmonella Rapid Test with three other Rapid Salmonella Rapid Test with three other Rapid Salmonella Methods. Letters in Applied Microbiol., 1989, 9, 161-164. R. Holbrook, J.M. Anderson, A.C. Baird-Parker and S.H. Stuchbury.

 
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