How the biodiversity loss in natural whey culture is affecting ripened cheese quality? The case of Trentingrana cheese

The present study investigated the dynamic changes in biodiversity population of lactic acid bacteria associated with the natural whey culture (NWC) of Trentingrana PDO cheese. NWC samples were collected from 14 dairies over a period of three years. Culture-independent analysis (pentaplex-PCR) highlighted the continued presence of Lactobacillus helveticus and Streptococcus thermophilus along with a drastic reduction of Lb. delbrueckii subsp. lactis presence. RAPD-PCR performed on 64 LAB strains isolated from 4 dairies pointed out an important decrease in the number of Lb. helveticus and St. thermophilus biotypes over time. This biodiversity loss was reflected also on the volatile organic compounds produced by the NWC isolates. Our results indicate that to preserve the complex pattern of cheese flavour it will be necessary introduce technological innovations to protect the whey culture microbiota preventing adverse effect on typical cheese traits.