Microbial diversity and sensorial properties of malga cheese from Trentino (Italy) after long-term ageing period

Background: Malga cheeses are made in artisanal and seasonal dairies located in the Alps. This study was carried out to determine microbial diversity and sensorial properties of Malga cheese from Trentino (Italy) after long-term ageing period. The effects of adding the Fermalga Bacterial Pools (FBP) on microbiota biodiversity of cheese were also evaluated. Methods: Populations of Lactic Acid Bacteria (LAB), mesophilic/thermophilic lactobacilli, mesophilic/thermophilic lactococci, coliforms, Enterococcus sp., and Streptococcus sp. was evaluated by plate count in 38 cheese samples after 6 and 16 months of ageing. Sensorial analysis of cheeses was performed by a panel of 30 expert judges. Statistical analysis of the data was carried out using STATISTICA v. 8.0. Results: The total microbial count of medium-aged (6 months) cheeses was significantly (p<0.05) higher than that of long-aged (16 months) cheeses. Coliforms as well as Staphylococcus sp. were not detected in all samples. Thermophilic LAB were the relevant (45%) population in cheese made by FBP; while mesophilic LAB, mainly lactobacilli were the relevant (87%) population in the non-inoculated cheeses. The sensorial scores of 16 months-aged cheeses were significantly (p<0.05) higher than that of 6 months samples. However, there was no significant (p>0.05) difference between sensorial scores of Fermalga and non-Fermalga cheeses. Conclusion: The protection of traditional fermented foods can occur by innovative technologies, making them safe without altering their typical features. This preliminary investigation on the characteristics of Alpine Malga cheeses showed that the addition the FBP had no undesirable effect on the organoleptic characteristics of the cheeses.