Objective: This study describes an effective educational program to improve children's knowledge about characteristics of microorganisms and food contamination, and their personal hygiene behaviors. Materials and Methods: Between November 2011 and March 2012, a health campaign, targeted at fifth-grade students of 12 public primary compulsory schools, was conceived. Participants were divided into two classes, a theoretical class and a practical class based on two different teaching approaches. To address children's knowledge and behaviors on the program topics and to monitor the effectiveness of the health campaign on changing pre-existent concepts and habits, pre- and post-intervention questionnaires were administered both to students and parents. Poisson and binomial mixed models were performed. Results: Two hundred forty-nine children were enrolled. Results show an overall improvement in children's knowledge both for the practical and theoretical classes (incident risk ratios [IRRs]: 1.2, 95% confidence interval (CI) 1.1-1.2, p