In which of the following can gluten be hidden?

Gluten is a mixture of proteins found in wheat and other grains, which means it can be present in products derived from these grains. Beer is a beverage that is typically made from barley or wheat, both of which contain gluten. As such, any beer made with these grains would inherently have gluten, making it a source where gluten can be "hidden."

In contrast, fresh fruit, milk, and chicken are naturally gluten-free foods. Fresh fruit does not contain gluten as it is derived from plants that do not have these proteins. Milk, being a dairy product, is also free from gluten. Similarly, chicken, which is a protein source, does not contain gluten unless it has been processed or prepared with gluten-containing ingredients or sauces.