Catering Gluten-Free When Simultaneously Using Wheat Flour

J Food Prot. 2016 Feb;79(2):282-7. doi: 10.4315/0362-028X.JFP-15-213.


A European law on gluten-free (GF) labeling came into force in 2012, covering foods sold prepacked and in food service establishments, and a similar U.S. Food and Drug Administration (FDA) regulation covers GF labeling from August 2014. Gluten is found in the grains wheat, rye, and barley. A common source of gluten in the kitchen is wheat flour. This research aimed to determine variables that have a significant effect on gluten contamination in commercial kitchens when wheat flour is in use and to establish controls necessary to assure GF production. A pilot study was used to test the following hypotheses: (i) increasing duration of exposure to wheat flour would increase gluten contamination, (ii) increasing distance between the site of preparation and the site of wheat flour would reduce gluten contamination, (iii) the use of a ventilation hood would decrease gluten contamination, and (iv) the use of a barrier segregating the site of preparation of a GF meal and the use of wheat flour would decrease gluten contamination. Petri dishes containing GF rice pudding were placed in three directions at increasing distances (0.5 to 2 m) from a site of wheat flour use. A barrier was in place between a third of samples and the site of wheat flour. After wheat flour was handled for 0.5 and 4.0 h, petri dishes were sealed and the contents were analyzed for gluten. The experiment was duplicated with the ventilation hood on and off. The pilot study revealed that a distance of 2 m from the use of wheat flour was required to control gluten contamination at ≤20 ppm if wheat flour had been in use for 4.0 h. The identified control of distance was tested in five different study sites. In each of the study sites, a test meal was prepared a minimum of 2 m away from the site of wheat flour use. Although kitchens vary and must be considered individually, the established control of a minimum 2 m distance, along with good hygiene practices, was found to be effective in preparing GF meals at all five study sites.

MeSH terms

  • Equipment Contamination / prevention & control
  • Flour / analysis*
  • Food Handling / instrumentation
  • Glutens / analysis*
  • Pilot Projects
  • Triticum / chemistry*
  • United States


  • Glutens