Re: Milk allergy backfire
It could just be a coincidence. And dairy takes 2 to 3 weeks to get out of baby and mama's systems, so if he's affected by dairy, it's still affecting him.
What you eat does change the taste of your milk a bit, but I don't think it's a huge change. If you eat a lot of garlic or curry, for instance, baby will taste a bit of it in your milk. I don't think ordinary foods that you were probably eating anyway to some degree before would make a big difference.
I can't really comment on beef or caramel coloring, but when I wondered what was bothering my DD, I did cut out soy, too.
ETA: how old is your baby?
Catherine, tandem nursing mama to Preschooler Girl 9/08 and Toddler Boy 3/11
Breastfeeding for 4 years and counting!