Efficacy of Lactic Acid Bacteria Isolated from Some Fruits and Vegetables

Document Type : Original Article


THE CURRENT study was conducted to assess the extent of probiotics Lactic acid bacteria(LAB) in some fresh fruits as (peach, pashmala, ,apricot, grape, banana, yellow and red apple, Kiwi, guajava and orange) and some vegetables as (cucumber, tomato and strawberry). Thirty eight (38) isolates were Gram positive and catalase negative, 20 isolates belong to genus Lactobacillus and 18 belong to Lactococcus sp. According to biochemical reactions 13 isolates out of 38 were identified as 5 belong to L. plantarum, 2 isolates to L. brevis, 3 to Pediococcus sp. and 3 to Leuconostoc sp. Antagonistic activity of these isolates against Staphylococcus aureus ATCC6538, Escherichia coli ATCC8739, Pseudomonas aeruginosa ATCC 9027 and Salmonella typhimurium ATCC22 bacteria were assessed. It noticed that some isolates have a negative effect against all the tested isolates, other isolates affected on some tested strains and some isolates affected on all tested strains. In all the cases that have affected the inhibition area not exceeding 5mm. Sensitivity to commercial antibiotics were studied and it noticed that the isolates showed sensitivity to antibiotics varies among the least sensitive isolate, Leuconostoc sp. 26, where it was sensitive to only one antibiotic and the most senior sensitivity was L.plantarum 5 and 27 strains which showed sensitivity to 11 out of 14 antibiotics that were tested . Probiotics characteristics showed that all isolates were sensitive to low stomach pH3 and for 0.3% bile salt, only six isolates were resistant to bile salts 0.3% concentration after 4h; four of Lactobacilli strains (L.plantarum 1, 5 and 38 and L. brevis11 ) and two of Lactococci (Pediococcus sp. 18 and Leuconostoc sp. 21) .