Effects of plasma treatments applied to fresh ricotta cheese

The aim of this study was to test two different innovative plasma assisted approaches to prolong ricotta shelf life. In one test the ricotta cheese is directly exposed to the plasma effects, and in the other one the plasma is indirectly applied (i.e. blowing the plasma effluents on the substrate). This last approach is innovative and very promising because in this way, plasma treatment can be assured at moments or at places where no plasma source can be used or is available. To the aim, treated and untreated samples were stored at 4 C for a period of 8 days, during which microbiological, sensory analyses and pH measurements were carried out. Tests were repeated more times to also taken into account product variability. Results highlighted that both treatments in all tests were effective to control microbial proliferation and preserve sensory quality. Specifically, a significant shelf life prolongation was recorded, ranging between 50% and 100%, depending to the type of treatment and on the initial microbial contamination.Industrial relevance: Both direct and indirect plasma treatments tested have led to a shelf life increase of up 2 days, which is a very promising result for a fresh product such as artisanal ricotta. The current paper offers the first example in literature of "gentle " and efficacious treatment of fresh perishable products by gas effluents plasma enriched by reactive oxygen or nitrogen species. The easy implementation of the proposed indirect approach and the easily customizable CAP system at room temperature could gain great attention from fresh dairy sector, with economic advantages and benefits also for the environment.