## 3 Results and Discussion
In the analyses performed, the presence of contamination (gluten concentration > 20 ppm) was observed using the ELISA technique in 10 (6%) of 173 samples. In an American investigation, 1.1% of 275 goods with the claim \"gluten free\" contained more than 20 ppm of gluten [20]. In that study, the authors used two different ELISA kits, namely wheat protein sandwich ELISA (181 GD) and R5 monoclonal-based Ridascreen Gladin sandwich ELISA (R7001). [PERSON] et al. [10] gathered 200 samples at random throughout Italy, 93 of which were marked \"gluten free\" and 107 of which were naturally gluten-free despite not bearing the label. In the analyses, gluten levels  
Figure 2: Evaluation of the analyzed samples according to the Codex Alimentarius. n = number of samples. exceeding 20 ppm were detected in 1% of the samples labeled \"gluten free\" and 8% of the naturally gluten-free samples using the R5 ELISA Kit. In essence, gluten contamination may arise from any combination of agricultural, milling, and manufacturing practices [6]. Naturally gluten-free foods may become contaminated at any point in the food chain, including during their growth, harvest, storage, or processing. This causes gluten-free foods to turn into gluten-containing foods [12]. In the study of [PERSON] et al. [21], when 22 naturally gluten-free seeds, grains, and flour samples were analyzed to detect gluten levels through the use of the Ridascreen Gliadin sandwich R5 enzyme-linked immunosorbent assay, it was determined that 32% of the samples had gluten levels higher than 20 ppm. When samples obtained from Canadian stores that sell naturally gluten-free flours and starches were tested for gluten contamination using the ELISA method, 1.1% of 268 samples with a \"gluten free\" label and 10.1% of 298 samples without a \"gluten free\" label were found to be gluten-free. It has been reported that naturally gluten-free foods can become contaminated (gluten levels \(>\) 20 ppm) [22]. A study conducted in India evaluated gluten contamination in various cereal-based food products (\(n=160\)) made from naturally gluten-free cereals, using the ELISA method. The study found that 46.5% of the tested products had a gluten content below 20 mg/kg. The study also reported that 35.9% of the flour samples made from naturally gluten-free grains and 85% of the oat samples purchased from local mills were contaminated with gluten. Among the products labeled as gluten-free (\(n=51\)), only five samples showed gluten contamination above 20 mg/kg [23]. It has been observed that the supply of products from local producers increases the risk of gluten contamination. In the study of [PERSON] et al. [5], the development of 3141 grain-based gluten-free food products was observed using the enzyme-linked immunosorbent test (ELISA) technique from 1998 to 2016. Eight distinct categories of chosen foods were looked at: flours, pasta, snacks, breakfast cereals/bars, yeasts, bakery goods, breads, and doughs. They were split into two categories: those with gluten-free labeling and those that are only declared to be gluten-free. As a result, 371 samples tested positive for gluten, with breakfast cereals and bars having the highest contamination levels. There has also been a decrease in gluten detection over the years. In fact, while the snack and yeast groups have a high gluten content, they have entered the gluten-free category over the years. Regarding the proportion of contaminated products (7%), as well as the amount of gluten present in such products, our research indicates that there is little gluten contamination in gluten-free products available on the Turkish market.