Hi Suzanne,
My experience is a little different, but has been life-long: About 5 days before I get any symptoms of a chest infection, the taste of coffee changes!
I love coffee, but it suddenly tastes like I'm drinking dirt! It is always the very first signal that an infection is coming.
Weird, I know, but I use this warning to make an appointment for the in-coming infection. By the time the infection hits, I am in the doctor's office.
Yes, I would say that dairy does seem to increase the sputum production, but it is an individual thing... if it makes things worse, then avoid.... being careful to make adjustments in your supplements to off set the short fall in your nutrition levels.
All the best.
When I have told my doctors, they just nod and say nothing!