The antibacterial activity of citrus
essential oils was tested against human pathogenic bacteria.
The results presented in Table 4 showed great differences
in the activity between citrus species and during ripening
stages. The oils were effective against Gram (+) and Gram
(−) bacteria, with a major activity against S. aureus and E.
coli. Bitter orange, lemon, and orange were effective against
P. aeruginosa only at maturity while mandarin oil remained
inactive against this strain. In accordance with our finding,
Espina et al. [12] reported no activity of the peel oil extracted
from mature mandarin fruit against P. aeruginosa. On the
other hand, lemon and mandarin essential oils extracted
from immature fruit exhibited the highest antibacterial
activity against E. coli which was comparable of positive
control activity. In the case of S. aureus, the oils were mostly
active at mature stage with mandarin oil showing the highest
antibacterial activity.