Time-course estimation of evaporated water fluxes together with mean surface water activity in uncooked pressed cheeses during ripening using a purpose-built micro-bioreactor

During cheese ripening, surface water activity controls microbial flora activity and aroma development, essentially shaping the organoleptic properties of the cheese. An experimental micro-bioreactor was set up using air-product water balance to non-destructively estimate the time-course of mean water activity at the cheese surface under well-controlled airflow ripening conditions. Six trials were performed using this experimental device on uncooked pressed cheeses ripened until 30 days. These trials highlighted (1) the effects of a low air velocity and high relative humidity on the water exchanges occurring at the cheese surface, demonstrating strong surface sensitivity to external ripening air conditions, and (2) a close interaction between surface microbial flora development and the water transfers occurring both from cheese core to surface and at the surface itself, although further micro-bioreactor ripening trials are needed to fully clarify this interaction.