RI-ERP-FINALACTION-Recommendations

OMAMAN-20 C/ In House Validation Report ERP Use Only - March 2015

3.7

Sample Preparation

3.7.1 General recommendation 3.7.1.1 Store samples in a cold and dry room protected from light. Ensure that no cross- contamination takes place.

3.7.1.2 Carry out the sample preparation in a room isolated from the dip stick procedure.

3.7.1.3 Clean surfaces, glass vials, mincers and other equipment with 60 % ethanol (see 3.6.2) also after use for the next sample. 3.7.1.4 Airborne cereal dust and used laboratory equipment may lead to gliadin contamination of the assay. Therefore, wear gloves during the assay and before starting with the assay. 3.7.1.5 If necessary, check for gliadin contamination of reagents and equipment with the RIDA®QUICK Gliadin (Art. No. R7003). 3.7.1.6 Keep in mind that solid samples can be inhomogeneous, therefore ground a representative part of the samples very well and homogenize before weighting. 3.7.1.7 The sample extraction with ethanol should only be used for raw material that were surely not heated and not processed. 3.7.1.8 All supernatants obtained after centrifugation can be stored in a tightly closed vial in the dark at room temperature (20-25 °C) up to four weeks. 3.7.2.1 Liquid samples -- Mix 1 mL of a representative, homogeneous sample with 9 mL 60 % ethanol solution (see 3.6.2). For soy milk add additionally 1 g of skim milk powder (3.2.7). Follow 3.7.2.5 3.7.2.2 Pasty samples -- Weigh 1 g of a representative, homogeneous sample and add 10 mL 60 % ethanol solution (see 3.6.2). For soy milk products add additionally 1 g of skim milk powder (3.2.7). Follow 3.7.2.5 3.7.2.3 Solid samples -- Weigh 1 g of a representative, homogeneous sample and add 10 mL 60 % ethanol solution (see 3.6.2). For soy containing products add additionally 1 g of skim milk powder (3.2.7). Follow 3.7.2.5 3.7.2.4 Samples with non-homogenous gliadin contents (e.g. meat, sausages) -- In these samples, gliadin may not be distributed equally. Therefore, use a higher sample input and increase the volume of 60% ethanol (see 3.6.2) accordingly (keep ratio between sample amount and volume of 60% ethanol constant), e.g. weigh 20 g of sample and add 200 mL 60% ethanol (3.6.2). Follow 3.7.2.5 3.7.2.5 Further procedure for all samples (3.7.2.1 – 3.7.2.4) -- Mix thoroughly for at least 30 s (vortex). Centrifuge the sample (2500 g at least) at room temperature (20-25 °C) for 10 min.; alternatively, let the sample settle down and/or filtrate. Dilute 50 µL supernatant with 500 µL sample diluent (see 3.6.1) in the test tubes (see 3.1.6) and subsequently proceed with 3.8. 3.7.2 Sample preparation procedures: non-processed Homogenize a representative amount of the sample (5-50 g).

AOAC Research Institute Expert Revi w Panel Use Only

3.7.3

Sample preparation procedures: processed Weigh 0.25 g of a representative, homogeneous sample (pasty or solid) into a vial and add 2.5 mL Cocktail solution (see 3.6.4).

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RIDA®QUICK Gliadin Validation report 2015-01-14