Quality and shelf life of fresh cheese packed under vacuum and modified atmosphere

Proizvedeni svježi sir od kravljeg mlijeka pakiran je u atmosferi zraka, vakuumu te modificiranoj atmosferi s dva omjera plina (60% N2:40% CO2; 70% N2:30% CO2) te su uzorci skladišteni u hladnjaku 18 dana. Uzorci su izuzimani i analizirani svaka tri dana. Kiselost je padala (s početnih 4,66 na 4,47), a broj naraslih kolonija mikroorganizama postupno rastao tijekom skladištenja u svim uzorcima, s tim da su te promjene kod uzoraka pakiranih u modificiranoj atmosferi i vakuumu bile znatno usporene (kiselost ne pada ispod 4,50). Svi uzorci postigli su visoke senzorske ocjene (17,63 – 19,73), no uz minimalne razlike najbolje ocjene postigli su uzorci pakirani u modificiranoj atmosferi s omjerom plinova 70% CO2:30% N2 (prosječan broj bodova 18,26). Vrijednosti ostalih ispitivanih parametara također su pokazali kako vakuum i modificirana atmosfera znatno produljuju rok trajanja uz očuvanje fizikalno-kemijskih i senzorskih svojstava svježeg sira.After production process, the fresh cheese was packed under normal atmosphere, vacuum and modified atmosphere with two types of gases in different ratio (60% N2:40% CO2; 70% N2:30% CO2) and stored in fridge for 18 days. The analysis was conducted every three days. Results showed that during a storage period acidity (from 4,66 to 4,47) was decreasing steadily, while colonies of microorganisms were multiplying However, samples of a fresh cheese packed under vacuum and modified atmosphere retard the decrease of acidity (no result under 4,50) and microbiological growth. Scores of sensory evaluations were high for all samples (17,63 – 19,73) but the best result had a sample packed under MA with ratio 70% CO2:30% N2 (average score 18,26). Other analysis confirmed that packaging under vacuum and MA can prolonged shelf life of fresh cheese while preserving its physico - chemical and sensory characteristics