1-2 test 1-2 test the most widely used single unit test for salmonella the most widely used single...

1-2 Test1-2 Test

The most widely used The most widely used single unit test for single unit test for SalmonellaSalmonella

AOAC Official Method (989.13)AOAC Official Method (989.13)

1-2 Test 1-2 Test ®®

Immunodiffusion Immunodiffusion (Antibody-based detection method)(Antibody-based detection method)

Requires movement of salmonella specific antibodies Requires movement of salmonella specific antibodies and target antigen through semi-solid gel mediumand target antigen through semi-solid gel medium

Antibody movement - diffusionAntibody movement - diffusion Target antigen movement – motility of live Target antigen movement – motility of live SalmonellaSalmonella

cellscells

For Salmonella


Single test format – 1 test per deviceSingle test format – 1 test per device 2 Enrichment protocols2 Enrichment protocols

Low microbial / Processed foodsLow microbial / Processed foods Aerobic plate count <10,000 CFU/gAerobic plate count <10,000 CFU/g Product exposed to a processing step that Product exposed to a processing step that

reduces and controls bioburden (drying, freezing, reduces and controls bioburden (drying, freezing, cooking, etc…)cooking, etc…)

High microbial / Raw foodsHigh microbial / Raw foods Aerobic plate count >10,000 CFU/gAerobic plate count >10,000 CFU/g Products possess inherent antimicrobial or Products possess inherent antimicrobial or

bacteriostatic properties (spices)bacteriostatic properties (spices)

For Salmonella

Enrichment ProtocolsEnrichment Protocols

1-2 Test 1-2 Test

Raw / High Microbial Foods

BPW or Lactose broth @ 35 oC 24 ± 2h

PRE-ENRICHMENT

Iodine activated TBG

@ 42 o C 6-8 h BPW or Lactose broth

@ 35 oC 24 ± 2h

PRE-ENRICHMENT

SELECTIVE ENRICHMENT

Processed / Low Microbial Foods

Transfer to 1-2 Test @ 35°C 14 – 30 hours

Transfer to 1-2 Test @ 35°C 14 – 30 hours

Time to results:36 – 54 hours

Time to results:44 – 62 hours

1-2 Test - Procedure1-2 Test - Procedure

Position 1-2 Test unit with Position 1-2 Test unit with black cap up.black cap up.

Remove cap.Remove cap. Add 1 drop of Reagent #1 Add 1 drop of Reagent #1

(Iodine-Iodide Solution) to TT (Iodine-Iodide Solution) to TT Broth.Broth.

Replace cap and gently Replace cap and gently shake unit to mix.shake unit to mix.


Reposition 1-2 Test unit Reposition 1-2 Test unit with black cap up.with black cap up.

Remove plug with sterile Remove plug with sterile forceps and discard it.forceps and discard it.

This will allow communication between the two chambers.


Transfer 0.1 mL sample Transfer 0.1 mL sample into inoculation chamberinto inoculation chamber

For raw foods, transfer For raw foods, transfer 1.5 mL of sample/TT 1.5 mL of sample/TT mixture to empty mixture to empty inoculation chamber inoculation chamber (side-port)(side-port)


Position 1-2 Test unit Position 1-2 Test unit with white cap up and with white cap up and remove cap.remove cap.

Snip off tip of gel void Snip off tip of gel void former with shears and former with shears and discard tip.discard tip.


Add 1 drop of Reagent #2 Add 1 drop of Reagent #2 (Antibody preparation).(Antibody preparation).

Replace white cap.Replace white cap. Incubate.Incubate.

1-2 Test - Incubation1-2 Test - Incubation

1-2 Test should be incubated with white cap up.1-2 Test should be incubated with white cap up.

Use the adequate incubation temperature: 35 °CUse the adequate incubation temperature: 35 °C

Duration: 14 - 30 hoursDuration: 14 - 30 hours

Could be incubated individually or while held in Could be incubated individually or while held in incubation trayincubation tray

Inoculation Chamber: enriched sample for analysis

Motility Chamber: semi solid Agar based motility medium

Antibody well: Salmonella specific antibodies

Salmonella, if present, moves through the selective medium into the motility chamber.

Antibody diffuses into the motility chamber in a radial pattern.

As the Salmonella encounters the diffusing antibodies they are immobilized.

A characteristic three-dimensional Immunoband will be formed if the test is positive. Results are read visually.

Movement of Salmonella

Motility Chamber

Inoculation Chamber

Diffusion of 1-2 Test antibody Immunoband


Advanced Science. Simple to Use.

Antibody well

1-2 Test - Reading Results1-2 Test - Reading Results

A positive test is indicated by the A positive test is indicated by the presence of a white band that is presence of a white band that is U-shaped or meniscus-shapedU-shaped or meniscus-shaped

Immunoband is 3-dimensional and Immunoband is 3-dimensional and is seen in all planes while rotating is seen in all planes while rotating 1-2 Test unit.1-2 Test unit.

The shape of the immunoband The shape of the immunoband may vary from strain to strain. may vary from strain to strain. Refer to directions for use for other Refer to directions for use for other examples.examples.

1-2 Test – Performance Statistics1-2 Test – Performance Statistics

AOACAOAC®® Official Method of Analysis 989.13 Official Method of Analysis 989.13

Sensitivity: 98.2%

Specificity: 98.8%

False Negative Rate: 1.8%

False Positive Rate: 1.2%

1-2 Test Objection1-2 Test Objection

Only detects motile Only detects motile SalmonellaSalmonella

• Motility is a key criteria used to define the genus Salmonella (Edward’s and Ewing’s Identification of Enterobacteriaceae, 4th ed. 1986)

• There are only 2 non-motile species of Salmonella, host adapted to poultry with very low virulence to humans (S. pullorum and S. gallinarum)

• 9 studies of the presence and distribution of Salmonella in food, feed, and dairy products – 183 species isolated with only 1 non-motile (S. pullorum from poultry facility environmental samples)

1-2 Test - Benefits1-2 Test - Benefits

Labor SavingsLabor Savings

Minimal hands-on time

Processed foods- Lactose enrichment & transfer to 1-2 test

Raw foods – Single selective enrichment (TT)

Reduced media preparation

SpeedSpeed

Raw – 44 hours (2 days) Processed – 36 hours (next day)

Ease of useEase of use

Least complicated Salmonella test on the market

Easy to interpret

1-2 test 1-2 test the most widely used single unit test for salmonella the most widely used single...

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