A study of the cleaning and sanitizing of milk pipe lines

Abstract

The primary purpose of this investigation was to attempt to determine whether or not the stainless steel pipe line installation of the Virginia Polytechnic Institute creamery, composed of ordinary stainless steel, could be satisfactorily cleaned by circulation cleaning procedures as opposed to daily disassembly of the entire pipe line. To facilitate such a determination, two experimental periods of approximately thirty days each in duration were set up. In the first period the experimental pipe line was subjected to complete daily disassembly cleaning procedures. That is, each section of the line was disassembled, cleaned individually, and reassembled. In the second period the experimental line was subjected to in-place cleaning procedures. That is, the line was left completely intact and cleaning was accomplished by means of forced circulation of cleaning solutions in a manner comparable to the way the milk is forced through the line. The cleaning methods used in the second period necessitated the use or an acid cleaning solution twice weekly. Sanitizing in the first period was accomplished by the use of a chlorine rinse before use and in the second period both chlorine and hot water at 180 °F were used. The experimental installations consisted of fifty-six feet of raw milk line and twelve and one-half feet of pasteurized milk line.