ANTIMICROBIAL PROPERTIES OF HUMAN LYSOZYME TRANSGENIC MOUSE MILK

The antimicrobial properties of standard human lysozyme and the milk o f transgenic mice expressing human lysozyme were investigated using ba cterial strains important to the dairy industry. Standard human lysozy me was found to be effective at significantly slowing the growth of th e milk cold spoilage organism Pseudomonas fragi (P < 0.001), of a clin ical isolate of the mastitis-causing organism Staphylococcus aureus (P < 0.005), and of a nonpathogenic strain of E. coli (P < 0.05). Milk f rom transgenic mice secreting human lysozyme in their milk at an avera ge concentration of 0.38 mg/ml was found to be bacteriostatic against the cold-spoilage organisms Pseudomonas fragi and Lactobacillus viscou s and a mastitis-causing strain of Staphylococcus aureus, but not agai nst a pathogenic strain of E. coli. These results demonstrate that tra nsgenic animals producing human lysozyme in their milk can affect the microbial nature of milk.