Cross-Contamination with Gluten by Using Kitchen Utensils: Fact or Fiction?

Abstract

A risk of cross-contamination exists when preparing a gluten-free (GF) meal in kitchen facilities that usually handle gluten-containing (GC) foods. Cross-contamination with gluten may occur during the preparation or cooking process; however, published data are lacking on gluten cross-contamination from kitchenware. This study was conducted to determine whether cross-contamination occurs through shared domestic kitchenware and, if so, which cleaning method is most reliable for avoiding this cross-contamination. Kitchenware (wooden spoon, colander, ladle, and knife) previously used to cook and/or prepare GC foods was used for the preparation of GF foods (bread and pasta). The gluten concentration of the GF foods was then determined using an established enzyme-linked immunosorbent assay. A PCR assay was also used to detect the presence of wheat ω-gliadin DNA in the food samples. Three cleaning methods were assessed to determine the concentrations of gluten and wheat DNA in GF foods cooked with utensils cleaned directly after the preparation of GC foods. Contrary to our expectations, gluten was not detected in relevant and quantifiable amounts in our samples (<20 mg/kg). The cleaning method used did not influence gluten concentrations: all samples contained <10 mg/kg. Based on PCR analyses, the only sample with lower cycle threshold ( C) values (i.e., higher concentration of wheat DNA) was from the contaminated ladle used to serve GF pasta. This outcome led to the hypothesis that shared ladles pose a higher risk for contamination of GF foods than do shared wooden spoons, colanders, or knives. Cross-contamination with gluten in a kitchen environment may occur, but kitchen utensils used for preparing GC pasta and for cutting GC bread should not pose a relevant problem to patients with celiac disease, at least in a domestic environment.

Can We Cross Off Common Kitchen Practices as Causes of Gluten Cross-Contact?

“…15 Less is known about gluten transfer in the domestic setting. Similar to the study by Weisbrod et al, 11 a recent study by Studerus et al 9 tested kitchenware, including a wooden spoon, colander, ladle, and knife and also did not find unsafe levels of gluten transfer except for a contaminated ladle. 9 Based on these few studies, including the one in this issue, is concern about gluten cross-contact in common scenarios encountered in home or commercial kitchens overblown?…”

“…6 Expert opinion recommends cautious practices for gluten-free food preparation, although exactly what steps are needed to prevent gluten cross contact are unknown, because these recommendations are not based on rigorous experiments. [7][8][9] Given the considerable burden placed on the patient, family, and food industries to avoid gluten cross contact, a better understanding of the risks associated with culinary practices is needed. 10 In the current issue of Gastroenterology, Weisbrod et al 11 address this knowledge gap with a unique study of common kitchen practices that, surprisingly, found little evidence of gluten cross-contact.…”

Current guidelines for the management of celiac disease: A systematic review with comparative analysis

“…Patients should be instructed to avoid contaminating their gluten-free food by using separate cooking utensils and cooking surfaces[ 9 , 10 ]. At present, shared items can be safely used if thoroughly cleaned with soap and water between use[ 9 , 76 ].…”

Detection of Gluten in Gluten-Free Foods of Plant Origin

“…Despite the label on the packaging that states ‘gluten-free food’, such cross-contamination can occur if food containing gluten is also processed in the common facility. Cross-contamination occurs when gluten particles are transferred from one object to another, which increases the risk of exposure and adverse effects to those who are unable to tolerate gluten [ 31 ].…”