Tube feeding and excessive mucus secrtetion

Yes, it is possible an allergy to the caseinate (milk protein) is causing the mucus. Might try a soy or egg-based formula instead... or an amino-acid based formula that has no food proteins in it, just free amino acids instead.

I did a Google search for "soy based tube feeding" and got the following list:

http://www.google.com/#output=search&sclient=psy-ab&q=soy-based+tube+feeding&oq=soy-based+tube+feeding&gs_l=hp.3..0i22i30.2060.22442.0.22704.22.19.0.3.3.0.112.1282.18j1.19.0...0.0...1c.1.14.psy-ab.f-1v14qhAhY&pbx=1&bav=on.2,or.r_qf.&bvm=bv.47008514,d.eWU&fp=fc8c70451a7b0b51&biw=1110&bih=622

Some of these products may require a prescription. If your husband is on long-term tube feeding, he should be receiving services from a dietitian at least yearly; try also checking with the dietitian to see what formulas would best meet his needs.

 My mother has been being tube fed for over two years.  about six months ago, she developed excessive mucus and coughed all day and night.  Initially, because she is of advanced age, it was attributed to her inability to cough and swallow secretions.  Long story short, she was diagnosed with GERD,but the omeprazole was in a capsule that clogged the feeding tube.  She was prescribed Nexium in a powder form, had her esophagus stretched and she is no longer bothered with the incessant coughing and can get good night's sleep.