Sensory and Microbiological Evaluation of Traditional Ovine Ricotta Cheese in Modified Atmosphere Packaging

Ovine ricotta cheese is a traditional Sicilian dairy product characterised by high humidity and a short shelf life (2-4 days when refrigerated). The increasing demand for fresh food has prompted manufacturers to develop special packaging techniques, such as modified atmosphere packaging (MAP), that can extend the shelf life and maintain the organoleptic characteristics of ovine ricotta cheese. The aim of the present study was to evaluate the shelf life of fresh MAP-packed ovine ricotta cheese by monitoring the microbiological, chemical, physical and organoleptic characteristics of the product. Samples of a single batch were packed in MAP or vacuum packed and stored at 4°C for 24 and 7 days, respectively. Water activity, pH, physicochemical parameters and microbiological characteristics were examined. A sensory panel rated the product's main organoleptic characteristics (colour, odour, flavour and texture). Results showed that MAP controlled the development of any unwanted microflora, but did not affect the development of intrinsic lactic floras or chemical parameters. Sensory analysis revealed that overall the MAP-packed ricotta remained acceptable for up to 15 days of storage. The vacuum-packed ricotta cheese, however, showed a progressive deterioration in organoleptic characteristics from day 5 onward and therefore had a shorter shelf life. In conclusion, the ability of MAP to extend the shelf life of a traditional regional product (such as fresh ovine ricotta cheese) guarantees consumers a quality product and provides opportunities for manufacturers to expand their markets beyond national boundaries.