I used to babysit a little boy who was breastfed and his mom would leave expressed breast milk for him. I could smell it in his spit up and he’d be irritable all day if she ate any tomatoes. I would actually talk to her on the phone during the day and ask, “Did you eat tomatoes last night?” and she’s say that she had!
When I was nursing my three I could smell things like broccoli, and onions when they passed gas. I don’t know why and I never researched it, but somehow the gas producing elements do seem make it into the breast milk.