Inactivation of bovine leukemia virus-infected lymphocytes in milk.

The survival of bovine leukemia virus (BLV)-infected lymphocytes in milk was studied to determine whether treatments similar to those on a dairy farm would inactivate BLV. Bovine leukemia virus was found in milk stored for 72 hours at 1.1 C (34 F); milk constituents, such as protein, total solids, minerals, fat, and somatic cell concentration did not affect the presence of BLV. Infectivity also was found in the cream layer of milk. Pasteurization at 63 C for 30 minutes did inactivate BLV-infected lymphocytes.