Membranes of Mammary Gland. VII. Stability of Milk Fat Globule Membrane in Secreted Milk

Milk samples obtained from cows i h after normal milking were separated into milk fat globule and serum fractions at intervals during 96 h of quiescent incu-bat_ion. Fat globule membrane phospholipid decreased only slightly and structural enzymes 5'-nucleotidase and adenosine triphosphatase did not decrease during the 96 h after collection of milk. These results together with previous observations argue against recent suggestions that the membrane surrounding milk fat globules is lost by vesiculation and shedding.