X-ray irradiation as a valid technique to prolong food shelf life: The case of ricotta cheese

The sanitising effects of X-rays were studied on ricotta cheese at intensities of 0.5, 2 and 3 kGy, using products manufactured artisanally and industrially. Microbiological, sensory and pH evaluations were performed during refrigerated storage. The artisanal ricotta irradiated at the two highest intensities (2 and 3 kGy) remained acceptable for more than 20 days, whereas the untreated samples became unacceptable after only 3 days of storage. The shelf life of the product irradiated at 0.5 kGy was limited to 14 days, due to the appearance of sensory defects. The industrial product irradiated at all X-rays intensities recorded a significant shelf life prolongation up to 84 days compared with the control, which was rejected after 40 days due to sensory defects. The results show that X-ray treatment can significantly prolong the shelf life of ricotta cheese, boosting the marketability of this fresh dairy product far from the local production sites.