Abstract
Bacteriocin-producing Lactococcus lactis strains were evaluated for their ability to control Listeria monocytogenes in traditional Moroccan lben (cultured milk). Results demonstrated that the pathogen decreased below detectable levels within 24 hours in fermented samples inoculated with bacteriocin producers, while surviving for 6 days in uninoculated controls. This biocontrol approach offers a natural alternative to chemical preservatives in dairy safety.
Background
Listeria monocytogenes is a major foodborne pathogen of particular concern in dairy products. Traditional Moroccan lben, a fermented milk drink, is consumed widely and may be susceptible to contamination during artisanal production.
Study Design
Bacteriocin-producing Lactococcus lactis strains isolated from dairy environments were characterized and used as protective cultures in artificially contaminated lben samples stored at refrigeration temperatures.
Results
- L. monocytogenes counts fell below the detection limit within 24 hours in cultures containing bacteriocin-producing strains
- In control batches (no protective culture), the pathogen survived for up to 6 days
- The protective effect was attributed primarily to bacteriocin production rather than competition for nutrients or pH reduction
Conclusion
Bacteriocinogenic L. lactis cultures represent a viable biocontrol strategy for enhancing the safety of traditional fermented dairy products in Morocco and similar contexts, without compromising sensory quality.