Screening for potential new probiotics based on safety, probiotic properties, antimicrobial activity and technological performance of lactic acid bacteria strains isolated from fermented foods and animal microbiota

Abstract

Aims: Over the past 20 years, probiotic microbes have been added to various foods.In this regard, several aspects, such as safety, functionality and technological features, must be taken into consideration when screening probiotic bacteria.This study focused on isolating and characterizing lactic acid bacteria (LAB) strains from various sources in the Tangier region of Morocco to assess their potential as probiotics and biocontrol agents in the food industry. Methodology and results:The present study was conducted in the Tangier region (North of Morocco) from various sources, including fermented table olive, Lben, cheese, camel and goat feces.In addition, the study involved 16S rDNA sequencing, which led to the identification of 1 Leuconostoc mesenteroide, 4 Lactobacillus plantarum, 1 Enterococcus faecalis and 33 Enterococcus faecium.The strains were subjected to a safety examination and evaluated regarding their functional features.Furthermore, the presence of vanA and vanB genes was detected using PCR for Enterococcus isolates.Most strains tested for probiotic assessment demonstrated high survival rates at low pH and bile salts, along with the presence of stomach and digestive enzymes, auto-aggregation and biofilm potential.Similarly, these strains, including Lactobacillus plantarum 14.2 and 14.4, exhibit an effective defence mechanism against enteric and food-borne infections by co-aggregating with pathogens such as Listeria monocytogenes, Escherichia coli, Salmonella typhimurium and Staphylococcus aureus.Conclusion, significance and impact of study: Research findings show the new LAB strain's advantageous traits, establishing E. faecium 1, L.plantarum 14.2 and 18.5 as strong candidates for use as alternative biocontrol agents in the food industry.