I'm a real blonde

I must be a real blonde for sure. Got this joke sent to me, and have to admit I fail to get the joke...this is a disaster! But what's funny with pasteurized? Is this a word joke?? Explanation would be nice (and yes, you're allowed to laugh at me being a "real" blonde). A blonde heard that milk baths would make her beautiful. She left a note for her milkman to leave 25 gallons of milk. When the milkman read the note, he felt there must be a mistake. He thought she probably meant 2.5 gallons. So he knocked on the door to clarify the point. The blonde came to the door and the milkman said, "I found your note asking me to leave 25 gallons of milk. Did you mean 2.5 gallons?"The blonde said, "I want 25 gallons. I'm going to fill my bathtub up with milk and take a milk bath so I can look young and beautiful again. "The milkman asked, "Do you want it pasteurized?" The blonde said, "No, just up to my tits. I can splash it on my face".