Volatile oils of peel fruits of Balady orange and Grapefruit were extracted by steam distillation and cold pressed methods, those that of Mandarin and Lemon were extracted by steam distillation only. Bacteriological experiments showed that volatile oils obtained by steam distillation method are strong inhibitors of the in vitro development of Pasteurella multocida, Salmonella gallinarum, Salmonella pullorum and Escherichia coli than that of pressed method and chloramphenicol.