Some San Diego Area Restaurants Designated as Dedicated Gluten-Free (note, we do not do our own testing on these products, we are just passing on from these restaurants).
Depending on the (small sample size) studies available, 10 mg of gluten per day is at this time generally considered to be the tolerable threshold for adults with celiac to consume (see (1) the National Institute of Health's Health Hazard Assessment for those with Celiac Disease), although beyond that, researchers still do not understand the full spectrum of toxicity caused by smaller amounts of gluten ingested in individuals.
A recent (large sample size) meta analysis seems to indicate it may not be too hard to get to that upper safe threshold of gluten just from cross contamination or similar unintended gluten consumption. (2)
In a study conducted by Tricia Thompson, Anne Lee, and Thomas Grace, 32% of the naturally gluten-free grains and flours tested contained gluten in amounts greater than 20 parts per million.
Excerpt from GlutenFreeWatchdog.org: "Unfortunately, the Food and Drug Administration under the gluten-free labeling rule is NOT requiring manufacturers to test their labeled gluten-free foods for gluten contamination.
GlutenFreeWatchdog.org is a not for profit service which independently tests hundreds of packaged products with top-notch ELISA tests in triplicate to see how much gluten they really contain.
Click here to learn more about this service and how much it costs to subscribe.
Curious about what kinds of products they test? Click here for the list of categories and number of products she's tested.