Contribution des bactéries lactiques thermophiles à la qualité du yaourt

Abstract

This study, conducted at the Numidia dairy plant (Constantine) in 2025, highlights the technological and health-related roles of lactic acid bacteria, particularly Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, in yogurt production. In compliance with Good Manufacturing Practices, both physicochemical and microbiological analyses were carried out. The results showed that the product met the applicable standards. Furthermore, microbiological tests confirmed the total absence of pathogenic microorganisms, including Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, and Enterobacteriaceae. These findings confirm that the use of lactic acid bacteria not only ensures the production of yogurt with desirable organoleptic qualities, but also offers a safe and functional food product. Thus, this dissertation emphasizes the importance of incorporating beneficial microorganisms into the agri-food industry to meet the growing consumer demand for natural, safe, and health-promoting products.