Valtellina Casera PDO is a key cheese designation in the Valtellina region, utilizing over 30% of the milk produced by livestock farms in Sondrio. Its production is governed by a Production Specification Document (PSD), which emphasizes the cheese's link to its territory but lacks clarity in some aspects. This study evaluates the impact of cattle breeds on the cheese microbiota to inform PSD revisions that better represent production methods and preserve the unique traits of Valtellina Casera PDO. Milk from specific cattle breeds influences cheese profiles. The current PSD permits traditional breeds, including Brown Swiss, Holstein Friesian, Simmental, and their crossbreeds. Differences in cheese from these breeds may result in organoleptic variations. Brown Swiss milk could enhance the cheese's market value, promote sustainable farming, and justify a differentiated labeling for cheese made exclusively from Brown Swiss milk. To explore these differences, 12 cheese samples from Brown Swiss milk and 31 from mixed breeds were analyzed across three ripening stages. Microbiological analyses included lactic acid bacteria enumeration (rods and cocci, heterofermentative lactic acid bacteria and enterococci) using standard methods. DNA sequencing (16S rRNA) was performed using Illumina MiSeq, and fatty acid profiles were analyzed with an Agilent GC system. Microbiological results showed more homogeneous microbial levels in mixed-breed cheese compared to Brown Swiss cheese, which had higher heterofermentative bacteria and rod-shaped lactic acid bacteria. These differences persisted during ripening but were not statistically significant. Fatty acid profiles also showed no significant differences between the two groups. Sequencing produced an average of 45,056 reads per sample. Alpha and beta diversity analyses revealed no significant differences in microbiome richness or biodiversity between the two groups (Observed species index p-value = 0.9859, Chao1 p-value = 0.9953, Shannon p-value = 0.2901). In both cases, 90% of the core microbiota consisted of Streptococcus spp. and Lactobacillus spp. The findings confirm that microbiota composition is stable across breeds, and microbial or fatty acid profile differences are minimal. Nonetheless, a differentiated branding strategy for Brown Swiss milk cheese could enhance the cultural and economic value of Valtellina Casera PDO while maintaining its traditional identity.
Influence of cattle breeds on microbiota and quality of Valtellina Casera PDO Cheese
P. Cremonesi;C. Ceccarani;T. Silvetti;S. Morandi;F. Bonazza;M. Brasca;B. Castiglioni
2025
Abstract
Valtellina Casera PDO is a key cheese designation in the Valtellina region, utilizing over 30% of the milk produced by livestock farms in Sondrio. Its production is governed by a Production Specification Document (PSD), which emphasizes the cheese's link to its territory but lacks clarity in some aspects. This study evaluates the impact of cattle breeds on the cheese microbiota to inform PSD revisions that better represent production methods and preserve the unique traits of Valtellina Casera PDO. Milk from specific cattle breeds influences cheese profiles. The current PSD permits traditional breeds, including Brown Swiss, Holstein Friesian, Simmental, and their crossbreeds. Differences in cheese from these breeds may result in organoleptic variations. Brown Swiss milk could enhance the cheese's market value, promote sustainable farming, and justify a differentiated labeling for cheese made exclusively from Brown Swiss milk. To explore these differences, 12 cheese samples from Brown Swiss milk and 31 from mixed breeds were analyzed across three ripening stages. Microbiological analyses included lactic acid bacteria enumeration (rods and cocci, heterofermentative lactic acid bacteria and enterococci) using standard methods. DNA sequencing (16S rRNA) was performed using Illumina MiSeq, and fatty acid profiles were analyzed with an Agilent GC system. Microbiological results showed more homogeneous microbial levels in mixed-breed cheese compared to Brown Swiss cheese, which had higher heterofermentative bacteria and rod-shaped lactic acid bacteria. These differences persisted during ripening but were not statistically significant. Fatty acid profiles also showed no significant differences between the two groups. Sequencing produced an average of 45,056 reads per sample. Alpha and beta diversity analyses revealed no significant differences in microbiome richness or biodiversity between the two groups (Observed species index p-value = 0.9859, Chao1 p-value = 0.9953, Shannon p-value = 0.2901). In both cases, 90% of the core microbiota consisted of Streptococcus spp. and Lactobacillus spp. The findings confirm that microbiota composition is stable across breeds, and microbial or fatty acid profile differences are minimal. Nonetheless, a differentiated branding strategy for Brown Swiss milk cheese could enhance the cultural and economic value of Valtellina Casera PDO while maintaining its traditional identity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
