Work

Enhancing “Ewiss” cheese production using autochthonous lactic acid bacteria and Propioniciclava flava as an alternative to commercial propionic acid bacteria

Year: 2025

Type: article

Abstract: This study aimed to reinforce the link between Ewiss cheese and its geographical origin by using autochthonous starter cultures to develop a “natural Ewiss cheese” (NEC). Lactic acid bacteria (LAB) and propionic acid bacteria (PAB) were selected from local sheep milk cheeses. Streptococcus thermophilus strains (RC-UNIPASAAFM00189, RC-UNIPASAAFM00233, RC-UNIPASAAFM00239, and RC-UNIPASAAFM00249) were sourced from the University of Palermo culture collection, while Propioniciclava flava (RC-UNIPASAAFM01343) was isolated during this study. LAB were added as natural whey starters post-pasteurization, and Pc. flava was introduced as an adjunct culture when milk pH reached 6.4. Microbial dynamics were monitored from pasteurized milk to ripened cheese. LAB counts ranged from 2–3 log CFU/mL before starter addition, with thermophilic LAB dominating after curdling. After 9 months, PAB became more prevalent. Metagenomic analysis (Illumina sequencing) revealed Streptococcus and Lactobacillus as dominant genera throughout ripening. At 9 months, cheeses showed 28.19% protein and a rich free fatty acid profile, including 22.60% mono-unsaturated fatty acids, mainly oleic acid (19.17%), and moderate poly-unsaturated fatty acids. Thirty-one volatile organic compounds were identified, with acids, especially propionic acid, being most abundant. A control cheese was produced using commercial LAB and PAB from the same bulk milk for sensory comparison. Sensory analysis revealed that NEC made with autochthonous cultures scored higher than the control. These findings show that integrating Swiss cheese-making techniques with selected autochthonous strains enhances NEC’s sensory and biochemical qualities, supporting the diversification and valorisation of Sicilian dairy products.

Source: International Dairy Journal

DOI: 10.1016/j.idairyj.2025.106473