Belabbes, Souad2015-02-252015-02-252015-02-25https://dspace.univ-tlemcen.dz/handle/112/7432This work is revealed the existence of antagonistic effect betweèiic c swaiu «fit& gmm Ladococcus sp mares milk and pathogenic species by i1ifiï dise ïnhditory factors produced by these bacteria, which can be irganiv hages, bydrogen peroxide or bacteriocins. Ail pathogens were inhibited by lactic strains tested secrete organic acids, hydrogen peroxide and bacteriocins but flot lodge phages. Ail strains belonging to lactic Lactococcus lactis and Lactococcus diacetylactis one produce two types of bacteriocins one is sensitive to pepsin and 2ic oher to a proteinasee, they also produce bacteriocins such as glycoprotein id I w Iipoprolein. They operate on 900/9 ofpathogenic bactena. Mou sirains oflactic acid have a bacteriosiatic effect on pathogenic fora. Interactions between strains ofLactococcus can be achieved, and the selfinhibition except for strain Lclj3. Ail paihogens showed a significant sensitivity to nisin as zones of inhibition ranging li-om 9 mm to Enterobacter up to 18 mm for Bacillus cereus of collection.frinhibition ,nisine ,antagonisme ,bactéries pathogènes ,LactococcusThesis