Gluten (G12) Detection by Romer Labs AgraStrip


Background:  Gluten is the main group of proteins in grains and consists of prolamins (in wheat: gliadin) and glutelins (in wheat: glutenins) occurring in the same ratio.  Due to its physicochemical characteristics, gluten is used in food products as a binder.  Coeliac disease is an autoimmune disorder of the small intestine.  It is caused by a reaction to gliadin and the only effective treatment is a lifelong gluten-free diet.  Due to Codex Standard 118-1979, “gluten-free” products must comply with gluten levels (including prolamin fractions from wheat, rye, barley and oats) below 20 mg/kg (ppm) and “foods specially processed to reduce gluten content” must comply with levels between 20 and 100 mg/kg (ppm).

This analysis is intended to confirm the absence of Gluten in food, rinse waters and swab samples.


Method

Apparatus

Turn Around Time

Sample Required – Product Samples

Sample Required – Rinse Water

Sample Required – Swab Samples

Type of Test

Reportable Units

Detection Limit – Product Samples

Detection Limit – Rinse Water

Detection Limit – Swab Samples

AOAC 061403 Romer Labs AgraStrip Gluten G12

Romer Labs AgraStrip

Same Day for Swabs or 5-10 Business Days for Product

0.2 grams of a representative sample

0.5 mL Rinse Water

5cm x 5cm (25 cm2) or 10cm x 10 cm (100 cm2)

Lateral Flow Device; Test Strip

Product:  ppm = mg/L or Swabs:  µg/cm2

Lower Detection Limit:  5, 10, or 20 ppm Gluten

Lower Detection Limit:  0.35 ppm (35 ppb) Gluten

Lower Detection Limit:  4 µg/25 cm2 or 1 µg/100 cm2 Gluten


Analysis Description:  Immunological rapid test in lateral flow format for the detection of Gluten in food, rinse waters and swab samples (environmental samples).  The test kit uses a new monoclonal antibody called G12 that specifically recognizes the pathogenic fragment of the gliadin protein present in gluten.  This fragment is called 33-mer and triggers the auto-immune reaction in coeliac patients.  The extracted sample is transferred to an incubation vial that contains specific ready-to-use antibodies.  During the test, if the sampel contains Gluten, the sample reacts with a coloured conjugate (anti-gliadin 33mer monoclonal antibody-red-coloured microsphere) which forms a complex with the reagent on the strip.  This complex spreads along the membrane by capillary action and is therefore detected by the test strip.

Notes:  This assay is not appropriate for food products which are known to contain Gluten.  If the sample contains more than 1% (10,000 ppm) Casein, the assay will be overwhelmed and give a false-negative result.

Sampling:  Consideration must be taken that the food may contain an uneven distribution of Gluten (spot contamination).  It is important to provide a representative portion of food as only a small amount of material is tested.