Final full-text version of the paper available at: http://dx.doi.org/10.1016/j.femsle.2004.07.002.A food-grade strain with nisRK stably integrated into the genome, was constructed in order to implement the nisin-controlled expression system (NICE) in Lactobacillus casei ATCC393. Expression of β-glucuronidase (gus) reporter gene was employed to optimize the system, which has been successfully used to produce the main antigenic protein from Norwalk virus, opening new perspectives for producing edible vaccines.This research was supported by project BIO 2002–01458 from MCYT (co-financed by the PLAN FEDER from the European Union), Project QLK1-CT-2002–02388 (European Union) and grants 01/0976 and 01/3139 from Fondo de Investigaciones Sanitarias, Spain.Peer reviewed