Characterisation of Urda whey cheese: Evolution of main biochemical and microbiological parameters during ripening and vacuum packaged cold storage

In this study, the main biochemical and microbiological characteristics of Urda, a traditional Greek whey cheese, were determined during ripening at 19 ± 2 °C for 25 days followed by vacuum packaging and storage at 5 °C until day 360. Few differences in pH, water activity, acid degree value, moisture, salt, protein and fat contents were observed between Urda cheeses produced from sheep or goat milk whey at all sampling days (1, 25, 90, 180 and 360). Cheese microbiota was dominated by mesophilic lactic acid bacteria, but high numbers of enterococci, aerobic gram-negative bacteria and Enterobacteriaceae were also present. Increases in all the soluble nitrogen fractions of cheeses occurred, primarily during cold storage. Ketones and terpenes were the most abundant volatile compounds in fresh (1-day) sheep and goat cheeses, respectively, whereas free fatty acids were the most abundant compounds in mature (180-day) cheeses, followed by ketones.