Kernel‐based gluten contamination of gluten‐free oatmeal complicates gluten assessment as it causes binary‐like test outcomes

Abstract

SummaryGluten-free (GF) foods, whose claim compliance is controlled at the 'serving level', hold better chances of protecting gluten-intolerant consumers. This is particularly true for GF oatmeal, as oats are easily contaminated with gluten-rich kernels of wheat, rye and barley, which remain intact to the spoon as pill-like flakes. A single contaminant kernel in otherwise pure oats results in GF labelling noncompliance, thereby posing a risk to patients with coeliac disease. Our in-market survey of 965 GF oatmeal servings uncovered that one in fifty-seven servings exceeded the GF labelling maximum of 20 mg kg À1 (i.e. 20 ppm). The noncompliance pattern was 'binary-like', with kernel-based contamination the suspected pass/fail driver.We have highlighted probabilities of misassessment for various sample sizes in light of oat's natural propensity for kernel-based contamination and proposed use of attribute-based sampling for compliance assessment, thereby providing a way to assess/manage/control 'rates of servings containing a contaminant kernel' within acceptable limits with high confidence.Keywords Acceptance sampling, binomial, coeliac disease, ELISA, gluten, gluten-free, inference, in-market survey, oat. IntroductionCoeliac disease (CD) is a lifelong, genetic, autoimmune intestinal disorder that affects approximately 0.2-1.0% of the world population (Sanders et al., 2003;Catassi & Fasano, 2008;Mustalahti et al., 2010;Ludvigsson et al., 2013;Mooney et al., 2016). Patients with CD have to abstain from dietary intake of gluten proteins found in wheat, barley and rye, as these proteins trigger autoimmune destruction of the mucosa of the small intestine (Janatuinen et al., 1995). Members of a household that includes a patient with CD often choose to follow a GF diet as well, to avoid accidental consumption of gluten-containing food by the patient with CD. Increased numbers of consumers are also choosing to follow a GF diet (Sharma et al., 2015). As a consequence, GF food products are getting more popular in the marketplace (Sapone et al., 2012). To protect this growing number of consumers, food regulatory agencies have started to regulate gluten content in products with GF claims. For example, the US Food and Drug Administration (FDA) has decided that foods with GF claims should contain less than 20 ppm (i.e. mg kg À1 ) of gluten (Sharma et al., 2015). This has elevated the need for improved methodologies to determine whether grain-based product meets this standard. Oats are recognised as one of the most important whole grain foods, being rich in dietary fibre, B-complex vitamins (thiamin, niacin and riboflavin), iron and proteins (Comino et al., 2015;Rebello et al., 2016). To expand the dietary options of patients with CD, as well as those following a GF diet, many researchers have investigated the suitability of dietary inclusion of oats (Lundin et al., 2003;Thompson, 2003;Comino et al., 2011Comino et al., , 2015Londono et al., 2013;Tapsas et al., 2014). Although there has been debate whether oats present risks to...

Compliance assessment of US gluten‐free labeled oatmeal produced under a “Purity Protocol” indicates “Serving Level Compliance” not attained

“…These findings are comparable to recent research where GF oatmeal produced by two large US manufacturers utilizing mechanical/optical oat cleaning for their “gluten‐free”‐labeled oatmeal averaged 1 in 57 servings noncompliant (Fritz & Chen, ). This rate however was attained with the analytical standard of the time, namely use of a 0.25‐g test portion result from a ground serving as an estimate of overall serving gluten content.…”

Preparation and quality characteristics of gluten‐free potato cake

“…Wheat products, however, contain gluten, which can cause celiac disease and other allergic conditions (Armstrong, Hegade, & Robins, 2012; Fritz & Chen, 2017). Celiac disease is a lifelong intolerance to the gliadin and glutenin protein components of wheat and to similar proteins found in rye, barley, and oats (Ludvigsson et al, 2012).…”

Gluten‐free bakery and pasta products: prevalence and quality improvement

“…Gluten includes a mixture of over one hundred proteins prevalent in grains, for example, wheat, rye, spelt and barley (Wieser, 1996). For people born with certain health conditions, and as humans age, the gluten in wheat can cause problems (Armstrong et al, 2012;Aronsson et al, 2015;Fritz & Chen, 2017). There are three main forms that human reacts towards gluten intake: allergic (wheat allergy), autoimmune (coeliac disease, dermatitis herpetiformis and gluten ataxia) and immune-mediated (gluten sensitivity) (Sapone et al, 2012).…”