I designed and assembled my own vat pasteurizer that meets the requirements of the federal "Pasteurized Milk Ordinance". In 2005, there wasn't a commercial pasteurizer small enough for our herd size and my desire to make farmstead cheese with the last evening's milk combined with the morning milk. During my licensing process with the state, I took care to set up a satisfactory review process so that my state public health dairy inspector Alan Metro could evaluate this self-designed micro vat pasteurizer. I did not start purchasing components or arranging stainless steel fabrication of a cover until Alan had approved the concept design and reviewed a shop drawing of the fabricated vat cover which holds the pasteurization instrumentation.
The 2005 cost, excluding the cooktop, was just under $4,000 with two thirds of the cost in instrumentation.
Detail on the Massachusetts Microvat Pasteurizer including a materials list, operation guidance, and photos can be downloaded in .pdf format here.
Frank Kipe at MicroDairy Designs offers a turn-key stove top pasteurizer setup which can streamline your setup and review process.
In Fall 2012, we added a 26-gallon C. van't Riet pasteurizer. It's a suberb piece of equipment.