International Journal of Advanced Smart Convergence Vol.4 No.1 11-17 (2015) http://dx.doi.org/10.7236/IJASC.2015.4.1.11 Empirical Modeling of Fouling Rate of Milk Pasteurization Process : A case study Titik Budiati 1 , Nanang Dwi Wahyono 2 , Muh. Hefni 3 1 Food Technology, State Polytechnic of Jember, Jember, Indonesia titik.budiati@gmail.com 2 State Polytechnic of Jember, Jember, Indonesia nanangdwiw355@gmail.com 1 Food Technology, State Polytechnic of Jember, Jember, Indonesia muh_hefni@yahoo.co.id Abstract Fouling in heat exchanger becomes a major problem of dairy industry and it increases the production cost. These are lost productivity, additional energy, additional equipment, chemical, manpower, and environmental impact. Fouling also introduces the risk of food safety due to the improper heating temperature which allow the survival of pathogenic bacteria in milk, introducing biofilm formation of pathogenic bacteria in equipments and spreading the pathogenic bacteria to milk. The aim of this study is to determine the fouling rate during pasteurization process in heat exchanger of pasteurized milk produced by Village Cooperative Society (KUD) “X” in Malang, East Java Indonesia by using empirical modeling. The fouling rate is found as 0.3945 o C/h with the heating process time ranged from 0 to 2 hours and temperature difference (hot water inlet temperature and milk outlet temperature) ranged from 0.654 to 1.636 o C. The fouling rate depends on type and characteristics of heat exchangers, time and temperature of process, milk type, age of milk, seasonal variations, the presence of microorganism and more. This results will be used to plan Cleaning In Place (CIP) and to design the control system of pasteurization process in order to maintain the milk outlet temperature as standard of pasteurization. Keywords: empirical modeling, fouling, heat exchanger, milk, pasteurization. 1. INTRODUCTION Fouling on the surface of plate heat exchanger during pasteurization of milk, a complex process formed by protein and minerals, may reduce the efficiency of heat transfer and increase the dropping of pressure. The run time of heating process may be decreased because of the graduate blockage of milk that passed into IJASC 15-1-2 Manuscript Received: Jan. 10, 2015 / Revised: Feb. 5, 2015 / Accepted: Mar. 13, 2015 Corresponding Author: titik.budiati@gmail.com Tel: +60(4)6533813 Food Technology, State Polytechnic of Jember