MODELING PSEUDOMONAS FLUORESCENS BIOFILM FORMATION ON MARBLE, GRANITE AND STAINLESS STEEL AS A FUNCTION OF TIME AND TEMPERATURE MARCÍLIA SANTOS ROSADO, NELIO JOSE DE ANDRADE 1 , WILMER EDGARD LUERA PENA, ROBERTA TORRES CARELI, JOELMA LOPES PIAZZA and LUIS ANTONIO MINIM Food Technology Department University Federal of Viçosa 36570 000 Viçosa, Minas Gerais, Brazil Accepted for Publication August 7, 2009 ABSTRACT The adherence and biofilm formation of Pseudomonas fluorescens on marble, granite and stainless steel as a function of time (0–10 days) and temperature (4.5–36.8C) were evaluated using response surface methodology. The derived models show that the adherence of P. fluorescens to marble and stainless steel is affected (in decreasing order of importance) by time, time 2 and temperature and to granite by time 2 , time and temperature. Analysis of variance of the response variables showed that the models are significant and that they adequately represent the true relationships. The models were verified by experiments conducted under random combinations of temperature and time, and all the experiments verified that the proposed models are valid, suggesting that there is no tendency in the values predicted by the models. The number of cells adhered to stainless steel was lower than those adhered to marble or granite. All surfaces were able to support the adhesion of P. fluo- rescens and showed a well-established biofilm. PRACTICAL APPLICATIONS This study applied predictive microbiology to the task of preventing foodborne disease outbreaks in the food industry. Our results should contribute to food quality control, quality management, risk assessment, risk manage- ment hazard analysis by critical control point and good manufacturing 1 Corresponding author. TEL: +55-0313138992226; FAX: +55-0313138992208; EMAIL: nandrade@ ufv.br Journal of Food Process Engineering 34 (2011) 1623–1638. All Rights Reserved. © 2009 Wiley Periodicals, Inc. DOI: 10.1111/j.1745-4530.2009.00548.x 1623