Parmalat also used the occasion to install a new high-temperature, short-time pasteurization (HTST) system, and to replace the plant's hard-wired control system with a new Allen Bradley Programmable Logic Controller (PLC) and PC-based control system, according to John Miller, president of Seiberling Associates Inc. (SAI), Dublin, Ohio, the project's process/CIP engineer. The PLC controls all field devices from receiving to fillers via multiple distributed Input/Output (I/O) device drops while communicating to operators through Human Machine Interfaces (HMIs) in the plant's filler room, receiving room and newly constructed central control room.
The plant, which operates five days per week and receives raw milk seven days per week, produces a variety of pasteurized products, including skim milk, flavored milk, buttermilk and orange juice. Among other benefits, increasing the plant's capacity from 400,000 gallons of milk per week to 800,000 gallons per week enabled Parmalat to close a dairy operation in Columbus, Ga.