As I have mentioned many times in the past, it is imperative to diligently check labels on every product you buy. It doesn’t matter if you have been buying this product for the last 10 years and it has been gluten-free that whole time. The fact of the matter is that ingredients change. Manufacturer’s change suppliers or formulations to make their products better and inadvertently make a gluten-free product no longer gluten-free.
Case in point – Lipton’s Onion Soup Mix. This product has been gluten-free for at least the past 4.5+ years, but as Tiffany Janes mentions here, they have reformulated the product and it now contains barley. The barley is clearly marked on the package, so just be sure to check the label. As Tiffany mentions, there may still be old products out there that are gluten-free, just be cautious. If you are now left in a bind, check out this copycat recipe that you can make at home.
I know that I have been lax on more than one occasion when I have been in a hurry. I do always check when opening a product, but not always when I purchase it. So far I have been lucky and haven’t had to make any return trips back to the grocery store.