Restaurants often leave ingredients like sesame seeds and shredded cheese off the description of menu items where they are part of the meal.
If you are sensitive to any item included on the dish that comes to your table, I encourage you to send it back and ask the waiter to start including it in the list of ingredients on that menu item.
If enough people do this, the restaurant will notice wasted food > loss of revenue, and hopefully eventually list the ingredient on the menu.
This is not a selfish or petty act. This is preservation of your health.
I posted all the sentences above on my social media and received one comment trying to make me feel guilt about wasting food while people on Earth starve, that people with food sensitivities should tell the waiter their food sensitivities up front, and posed the question of why it should be up to a restaurant to cater to every single sensitivity.
People with food sensitivities already put in a lot of effort to order based on what they can and cannot have, and rely on the menu to do this.  I also find it important that people who run restaurants also do their part to be more upfront with what they are about to serve.
When I made the post, I was not thinking about every single ingredient in a gravy, sauce or the contents of the liquid part of a soup, because there can be several ingredients in there that are not noticeable to the naked eye, and in that case, it is helpful to ask if any of your food sensitivities are in it if you are super sensitive.  For instance, I will ask if a gravy, sauce or soup has dairy in it, because that is a significant food sensitivity for me and it will be in large enough amounts in a gravy, sauce or soup to cause my body to react to a level that is very uncomfortable.  People with food sensitivities may be willing to tolerate some of their less significant sensitivities in smaller amounts on a day of their choosing, so to ask the waiter ahead of time for a dish that DEFINITELY does not include them at all may be more restrictive than they actually choose to be that day.
A person knows their body better than a waiter does.  The waiter will be seeking to go much further with avoidance, which is appreciated and ideal for healing and better health, but not always what each person will do that day in a restaurant.  It is also none of your business either unless a person wants to tell you, because on the flip side, anyone with food sensitivities has probably come across people (including family members) who have said statements like, “oh a little is not going to hurt you.”  This can influence them to eat things that will inflame them more severely or more often than they actually want to allow for themselves.  There is a higher level of control a person can have over what they eat when other people are not persuading them against their best interest, and thus a potentially higher level of wellness longer term.  It is easy to think in all or none terms when it comes to diet, but for some, what I have described here may also be what it looks like, sometimes.
But I went on a tangent there.  When I made the post, I was particularly thinking about ingredients people can see with the naked eye, such as cheese and sesame seeds!
Here’s what I have seen time and time again: A restaurant is more likely to tell you a salad contains broccoli than it is likely to tell you it also contains cheese (dairy) or croutons (contains gluten), even though there are way more people sensitive to dairy and gluten than there are people sensitive to broccoli.  It statistically does not make sense to do this.  Sometimes restaurants will list 7 ingredients of a dish and leave off the last one that happens to be potentially the most common and well-known inflammatory food.
So I again bring up the the question of why it should be up to a restaurant to cater to every single sensitivity.  My rebuttal comment is that I wonder if the restaurants are catering to certain food industries instead, like the dairy industry.  And perhaps certain chefs are more interested in the art of presentation than the care of the health of their customers.
It is not much of an effort to include a couple more ingredients on the menu.  It is not too much of you, the customer, to ask the restaurant to do so.  I know you are not interested in wasting food, but from my viewpoint, the restaurant is conveying that they are okay with risking the wasting of food just to include a couple extra ingredients that weren’t on the menu and hoping you will not say anything and just eat it…because YOU don’t want to waste food.  See the issue?
If you want this to change, I encourage you to either send back your food and suggest they list all ingredients on the menu, OR ask if there are any other toppings or garnishes that will be included in your dish that are not listed on the menu.  This way, you can avoid them ahead of time, and also still suggest that they start listing this on the menu.  It is not always easy to totally remove something like sesame seeds or cheese from a dish the same way you would one leaf of mint.
Again, this is not a selfish or petty act. This is preservation of your health.