Gluten Contamination of Labelled Gluten-Free Food Products Marketed in China

Gluten has a central role in the pathogenesis of several gluten-related disorders, with coeliac disease being one of the most well-known. A rigorous gluten-free diet is recognized as the only safe and efficient coeliac disease therapy. This study intended to use the enzyme-linked immunosorbent assay...

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Main Authors: Yanjun Li, Qing Liu, Samuel Godefroy, Jingguang Li, Yan Chen
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/14/12/2025
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author Yanjun Li
Qing Liu
Samuel Godefroy
Jingguang Li
Yan Chen
author_facet Yanjun Li
Qing Liu
Samuel Godefroy
Jingguang Li
Yan Chen
author_sort Yanjun Li
collection DOAJ
description Gluten has a central role in the pathogenesis of several gluten-related disorders, with coeliac disease being one of the most well-known. A rigorous gluten-free diet is recognized as the only safe and efficient coeliac disease therapy. This study intended to use the enzyme-linked immunosorbent assay (ELISA) R5 Méndez method to determine gluten contamination in labelled gluten-free food products marketed in China and to evaluate the performance of two ELISA platforms (the Neogen Veratox<sup>®</sup> R5 and the Romer Labs AgraQuant<sup>®</sup> G12) for analyzing gluten, using R5 Méndez as the reference. In 2024, 119 prepackaged products labelled as gluten-free were purchased from internet suppliers. The results showed that among the 119 products, 13.4% contained gluten exceeding 20 mg/kg, and 5.0% contained over 100 mg/kg, ranging from 333.1 to 2737.4 mg/kg. When the threshold for gluten-free products was 20 mg/kg, the two ELISA platforms yielded results comparable to R5 Méndez. However, when the threshold was 10 mg/kg and 5 mg/kg, the McNemar <i>x</i><sup>2</sup> test showed significant differences between the proportions of positive results of the two ELISA platforms and R5 Méndez (<i>p</i>-value < 0.05); using R5 Méndez as the reference, the two ELISA platforms showed 53.1% to 70.3% positive predictive values, suffering the drawback of high false-positive results. When using stricter gluten limits of ≤10 mg/kg and ≤5 mg/kg, different ELISA platforms may produce different results for the same food product. These findings highlight the need for China to accelerate the development of national standards for gluten-free foods, and for food regulatory agencies to impose requirements of production that lead to the prevention of gluten contamination, confirmed by the possible monitoring of such compliance through routine sampling and testing. Such measures will no doubt contribute to protecting and improving the health of patients with gluten-related disorders.
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spelling doaj-art-95242c97e8ea4d9bbdb8865b3e68ec392025-08-20T02:21:01ZengMDPI AGFoods2304-81582025-06-011412202510.3390/foods14122025Gluten Contamination of Labelled Gluten-Free Food Products Marketed in ChinaYanjun Li0Qing Liu1Samuel Godefroy2Jingguang Li3Yan Chen4Research Unit of Food Safety, Chinese Academy of Medical Sciences (No. 2019RU014), NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100021, ChinaResearch Unit of Food Safety, Chinese Academy of Medical Sciences (No. 2019RU014), NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100021, ChinaFood Risk Analysis and Regulatory Excellence Platform (PARERA), Institute of Nutrition and Functional Foods, Laval University, Quebec, QC G1V 0A6, CanadaResearch Unit of Food Safety, Chinese Academy of Medical Sciences (No. 2019RU014), NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100021, ChinaResearch Unit of Food Safety, Chinese Academy of Medical Sciences (No. 2019RU014), NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100021, ChinaGluten has a central role in the pathogenesis of several gluten-related disorders, with coeliac disease being one of the most well-known. A rigorous gluten-free diet is recognized as the only safe and efficient coeliac disease therapy. This study intended to use the enzyme-linked immunosorbent assay (ELISA) R5 Méndez method to determine gluten contamination in labelled gluten-free food products marketed in China and to evaluate the performance of two ELISA platforms (the Neogen Veratox<sup>®</sup> R5 and the Romer Labs AgraQuant<sup>®</sup> G12) for analyzing gluten, using R5 Méndez as the reference. In 2024, 119 prepackaged products labelled as gluten-free were purchased from internet suppliers. The results showed that among the 119 products, 13.4% contained gluten exceeding 20 mg/kg, and 5.0% contained over 100 mg/kg, ranging from 333.1 to 2737.4 mg/kg. When the threshold for gluten-free products was 20 mg/kg, the two ELISA platforms yielded results comparable to R5 Méndez. However, when the threshold was 10 mg/kg and 5 mg/kg, the McNemar <i>x</i><sup>2</sup> test showed significant differences between the proportions of positive results of the two ELISA platforms and R5 Méndez (<i>p</i>-value < 0.05); using R5 Méndez as the reference, the two ELISA platforms showed 53.1% to 70.3% positive predictive values, suffering the drawback of high false-positive results. When using stricter gluten limits of ≤10 mg/kg and ≤5 mg/kg, different ELISA platforms may produce different results for the same food product. These findings highlight the need for China to accelerate the development of national standards for gluten-free foods, and for food regulatory agencies to impose requirements of production that lead to the prevention of gluten contamination, confirmed by the possible monitoring of such compliance through routine sampling and testing. Such measures will no doubt contribute to protecting and improving the health of patients with gluten-related disorders.https://www.mdpi.com/2304-8158/14/12/2025coeliac diseasefood contaminationglutengluten-free dietgluten-related disorderslabelled gluten-free
spellingShingle Yanjun Li
Qing Liu
Samuel Godefroy
Jingguang Li
Yan Chen
Gluten Contamination of Labelled Gluten-Free Food Products Marketed in China
Foods
coeliac disease
food contamination
gluten
gluten-free diet
gluten-related disorders
labelled gluten-free
title Gluten Contamination of Labelled Gluten-Free Food Products Marketed in China
title_full Gluten Contamination of Labelled Gluten-Free Food Products Marketed in China
title_fullStr Gluten Contamination of Labelled Gluten-Free Food Products Marketed in China
title_full_unstemmed Gluten Contamination of Labelled Gluten-Free Food Products Marketed in China
title_short Gluten Contamination of Labelled Gluten-Free Food Products Marketed in China
title_sort gluten contamination of labelled gluten free food products marketed in china
topic coeliac disease
food contamination
gluten
gluten-free diet
gluten-related disorders
labelled gluten-free
url https://www.mdpi.com/2304-8158/14/12/2025
work_keys_str_mv AT yanjunli glutencontaminationoflabelledglutenfreefoodproductsmarketedinchina
AT qingliu glutencontaminationoflabelledglutenfreefoodproductsmarketedinchina
AT samuelgodefroy glutencontaminationoflabelledglutenfreefoodproductsmarketedinchina
AT jingguangli glutencontaminationoflabelledglutenfreefoodproductsmarketedinchina
AT yanchen glutencontaminationoflabelledglutenfreefoodproductsmarketedinchina