Hello! Welcome to Beyond Soy!
Want some terrible news? Mayonnaise that is "made with olive oil" often still has soy in it. How about that?!?
Mayonnaise is a very difficult food to find in a soy-free variety. Since vegetable oil is a major component of mayo, soybean oil is present in pretty much every mayonnaise out there. One day, Ashley and I were looking for mayo at the grocery store and, because so many of them contain soy, we ended up reading the ingredient labels on pretty much every type of mayo available. We ruled the "normal" types out first, but then came to the specialty advertised ones.--the ones that say "made with olive oil" or "made with canola oil".
At first glance, these two options seem like pretty good choices. The manufacturer has clearly replaced the soybean oil in the mayonnaise with canola oil or olive oil. Wrong! They do use canola oil or olive oil (their advertising is technically correct), but they also often use vegetable (soybean) oil.
We think this is done for marketing purposes. Soybean oil is cheap, and therefore manufacturers want to use it to have the lowest cost to produce the mayonnaise. The mayo with canola oil or olive oil can be advertised as a fancier product, but the costs also increase if soybean oil is completely replaced. Therefore, manufacturers use a small amount of olive oil or canola oil with the bulk of the oil as soybean oil. This way they can rightly claim the mayo uses olive or canola oil, but the costs to produce the mayonnaise are kept low.
This is something we've found true across several products (not just mayo): the advertised "special product" doesn't preclude the use of the cheap, soy-based product. It illustrates the importance of always reading the ingredient labels to ensure that the entire product is soy-free!
We did eventually find more-expensive-than-normal mayonnaise that is soy-free, so it does exist. But the lesson here is to be careful when picking out products. Don't fall for specialty food advertising that doesn't say "soy free"!