One of the craziest places to find gluten, is in your spice rack. Yep. Processing again. On site cross contamination, is another issue. Here are 4 things to watch out for:
1. Bulk bins: anything in a bulk bin, including spices are at a much higher risk of cross contamination than those packaged at the factory. Gluten can enter the bin from the scops at the grocery store (no one remembers which scoop came from where, let's face it). Bulk items are usually not as strictly controlled at the factory site, either.
2. Blends - Spice, and Specialty salt/pepper: these often use an anti-coagulation agent that contains gluten.
3. Spices from India: Asafoetida (hing), in particular, is a popular spice that uses wheat flour to dilute/cut the spice. There are a limited number of companies (one for sure) that uses rice flour rather than wheat. However, though this spice is naturally gluten-free, it is almost always combined w/ wheat. In Indian restaurants, make sure your dish is not prepared w/ this spice.
4. Taco Seasoning -many, if not most, contain gluten.
In any restaurant, make sure they understand the importance of gluten-free spices, and use gluten-free spices. One brand that is widely accepted in the gluten-free community is McCormick brand - the single spices only, not the blends. But always check the labels.