OMB First to Final Action Recommendation Checklist 11-12-18

ERP - GLUTEN ASSAYS: AOAC 2015.05 FAR

2.5 Proficiency testing round DLA 10/2016: Allergens X – Gluten in “gluten‐free” Beer  Three different beer samples were provided which were produced by blending a gluten‐free pilsner  lager (sample b) with different volumes of a barley‐based pilsner (sample C) or a wheat‐based bright  wheat beer (sample A). 16 participants from Great Britain, Italy, Germany, Switzerland, Spain, Sweden  used the OMA 2015.05 ELISA (RIDASCREEN® Gliadin competitive, R7021). The proficiency test provider  was DLA (Dienstleistung Lebensmittel Analytik GbR, Ahrensburg, Germany; www.dla‐lvu.de ). 

3. Results and Discussion  3.1 Recovery and precision of spiked syrup around 20 mg/kg (hydrolyzed) gliadin  PWG gliadin in syrup 

Results from analysis of syrup spiked with PWG gliadin are depicted in table 1. Overall, recoveries were  within the 50% ‐ 150% recovery range that is recommended by Abbott et al. (2010). It should be  noticed that the assay is calibrated to a mixture of hydrolyzed gliadin, secalin and hordein in the ratio  1:1:1. Therefore, recoveries cannot be expected to be around 100% for intact wheat prolamins.  However, the PWG gliadin represents the worst case with no fragmentation/hydrolyzation at all.   As expected, the CV rose when concentration around the LoQ (5 mg/kg hydrolyzed prolamin) were  analyzed. In all other cases, CVs were quite acceptable below 13%. All spiked samples were corrected  for the measured concentration of the blank syrup. For a table with detailed results see annex 1.  Table 1. Mean concentrations, standard deviation (SD) and recovery of six independent   extractions of PWG gliadin‐spiked syrup samples  PWG gliadin (wheat) in syrup  spiked  mean*  SD  CV  recovery  mg/kg  mg/kg  mg/kg  %  %  30  46.9  6.11  13.0  156  21  27.9  2.60  9.3  133  16  22.1  1.07  4.9  138  12  13.3  0.65  4.9  111  9  11.6  1.37  11.8  129  6  9.13  0.72  7.9  152  3  2.62**  0.47  17.9  87  Blank (mean)  1.82  *   blank corrected  ** concentrations below standard 2 (5 mg/kg) were extrapolated using 2 nd  order polynomial function  Partially hydrolyzed gliadin in syrup  As can be seen in table 2, recoveries for syrup samples spiked with partially‐hydrolyzed gliadin were  around 60%. It should be kept in mind that the system is calibrated against a mixture of hydrolyzed  gliadin, secalin and hordein in the ratio 1:1:1. Since the R5 monoclonal antibody used in this ELISA  shows higher reactivity towards rye and barley, a recovery of less than 100% was expected for  hydrolyzed wheat‐based materials. Comparing the data from table 1 and table 2, it is obvious that the 

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