TITLE:
Use of Lactococcus lactis Subsp. Lactis Strains to Inhibit the Development of Pathogens
AUTHORS:
Abir Maalaoui, Abdesselem Trimeche, Pierre Guy Marnet, Yann Demarigny
KEYWORDS:
Lactococcus lactis, Minimal Medium, Pathogenic Bacteria, Antibacterial Activity, Barrier Effect
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.11 No.2,
February
27,
2020
ABSTRACT: Bovine mastitis affects the udder health and thus causing significant
economic losses. Probiotic products based on the use of lactic acid bacteria
(LAB) to limit pathogens multiplication and pre-infection risks can be an
interesting alternative to post infection allopathic treatment with antibiotics.
Lactococcus lactis is one of the most important bacteria used in dairy technology. In this
work, a total of 21 Lactococcus lactis subsp. Lactis strains, 20 from goat milk whey and one
strain from cow milk were used to evaluate their antibacterial activity against
four pathogenic germs responsible for mastitis: Escherichia coli, Staphylococcus aureus, Streptococcus uberis and Streptococcus agalactiae. The
nisin-producing cow milk strain was active against St. uberis and Str. Agalactiae using the well diffusion method. For the strains isolated from goat milk
whey, no antimicrobial effect was observed against these pathogens. However, a
different approach based on the growth of pathogenic bacteria interacting with
the Lactococcus lactis strains in a minimum medium was used to study the barrier effect of LAB.
The Lactococcus lactis strains S1 and S2 from goat milk whey depleted the growth of Sa. aureus, St. uberis and E. coli during 8 h and stopped the development of St. agalactiae.