Surface UV-C light treatments to prolong the shelf-life of Fiordilatte cheese

Abstract

Abstract The possibility to apply UV-C light technology to control surface contamination and extend the shelf-life of Fiordilatte was investigated. First, cheese was inoculated with Pseudomonas spp., exposed to UV-C light for increasing time up to 750 s to estimate the antimicrobial efficacy of the treatments. UV-C light penetration depth in Fiordilatte was also evaluated. Then, a shelf-life test was carried out on samples exposed to 0.1, 0.6, 1.2 and 6.0 kJ/m 2 UV-C light, compared to untreated control cheese. The samples were packaged with brine, stored at 9 °C and analyzed for microbial growth, sensory quality and pH. A germicidal effect of about 1–2 log cycles on Pseudomonas spp. and Enterobacteriaceae was observed during storage. UV-C light did not promote changes in terms of color, texture and surface appearance. With a minimum transmittance inside the product, this treatment showed an interesting surface microbial decontamination that prolonged cheese shelf-life. Industrial relevance Considering that dairy industry represents one of the most important components of the Italian food system, the present work focused on the utilization of UV-C light to preserve one of the most important milk-derived Italian fresh cheese, Fiordilatte, which totalized a consumption of about 20 kg per capita per year in the world. Interesting results were recorded on treated samples, above all at specific UV-C light fluence values (6 kJ/m 2 ). The control of microbial proliferation in these treated samples allowed prolonging shelf-life by 80% compared to untreated cheese. The technique is very rapid and simple to be scaled up; after proper optimization of light parameters, it could be applied at industrial level to prevent surface post-process contamination of Fiordilatte that generally represents the main factor responsible for product deterioration and its short shelf-life.