Bacteria Source no. Inhibition zone (mm) Populations Algerian population Tunisian population  (BB) Tunisian population (WB) C1 C2 C3 C4 C1 C2 C3 C4 C1 C2 C3 C4 Gram-negative Escherichia Coli ATCC10536 15b 8c 8c 8c 20a 8c 7c NA 15b 9c 10c 8c Salmonella - 14b 7c 7c 6c 12b 8c 6c 6c 11c 6c 9c 12b Gram-positive Staphylococcus aureus ATCC 6538 10c 7c 7c 8c 23a 22a 8c 1d 21a 19a 8c 8c Bacillus subtilis ATCC 6633 9c 8c 8c 8cc 12b 9c 7c 6c 10c 8c 8c 7c Listéria - 10c 7c 7c 7c 15b 8c 7c 7c 7c 9c NA 8c Where C1: 10μl of essential oil and C2: 1/10, C3: 1/20, C4: 1/30. Values followed by the same letter under the same line are not significantly different (Duncan’s multiple range test at P>0.05).

Table 2: Antibacterial activity estimated by diameter of inhibition of Myrtus communis L. essential oils isolated from Algerian and Tunisian population: (Black Ballouta: BB and White Ballouta: WB).