Abstract
Traditional dairy products (TDP) are a valuable source of lactic acid bacteria (LAB) for use in sustainable and natural food systems. This study examined the technology and biopreservative properties of LAB isolated from 167 dairy samples across 11 regions of Morocco. Among the 2,672 pure isolates, 531 presumptive LAB were selected for laboratory phenotypic evaluation, focusing on milk acidity, enzyme activities, stress resistance, and antibacterial efficacy against foodborne microorganisms. The acidity test revealed considerable intraspecies variability; notably, the top-performing outliers were isolates of Enterococcus faecalis and Lactococcus lactis, predominantly derived from Lben and the Tetouan region. Significant heterogeneity was also observed in enzymatic activity, with approximately 70% exhibiting proteolytic activity, 22% lipolytic activity, 43% esterolytic activity, and 42% amylolytic activity. In terms of inhibitory activity, 32% of the LAB isolates showed inhibition against the tested pathogens, with noteworthy suppression observed against Staphylococcus aureus (13%) and Listeria monocytogenes (15%). The most potent antibacterial activity was identified in isolates of Enterococcus faecium, Lactiplantibacillus plantarum, and L. lactis, which were isolated from Lben (Agadir), Milk (Fes), and Raib (Fes), respectively. Principal component analysis (PCA) and clustering identified three distinct functional clusters of isolates, shaped by geographical origin and dairy products type, with specialized traits in acidification, stress resilience, or enzymatic activity. Representative isolates (n = 84) from key clusters were identified by 16 S rRNA sequencing, encompassing 15 LAB species, dominated by L. lactis, Leuconostoc mesenteroides, Enterococcus spp. and Lpb. plantarum. This work represents the first extensive screening of LAB from Morocco, providing a valuable collection of strains and a foundational framework for developing tailored autochthonous starter or adjunct cultures for improved dairy fermentation and biopreservation.