Antibacterial effect of thyme, peppermint, sage, black pepper and garlic hydrosols against Bacillus subtilis and Salmonella enteritidis

Author: A. I. Al-Turki

Received 8 January 2007, accepted 12 April 2007.

Abstract

The antibacterial effect of thyme, peppermint, sage, black pepper and garlic hydrosols, widely used in food products as drinks and food additives, were tested for their inhibitory effects against Bacillus subtilis and Salmonella enteritidis. Single and combined hydrosols of previous common herbs were used to evaluate in vitro the antibacterial activity against these pathogenic bacteria. The obtained data showed that all of the tested herbal hydrosols demonstrated antibacterial activities against all of tested bacteria. Garlic hydrosols demonstrated stronger antibacterial activity against Bacillus subtilis and Salmonella enteritidis compared with thyme, peppermint, sage and black pepper. Combined extracts of thyme, mint and sage (1: 1 mixing ratio) had slightly higher antibacterial activity against Bacillus subtilis and Salmonella enteritidis compared with single plant hydrosols. Thyme hydrosols demonstrated higher antibacterial activity against Bacillus subtilis and Salmonella enteritidis compared with sage, peppermint and black pepper. Generally, single or combined common herbal hydrosols had inhibitory effects against the tested pathogenic bacteria. Therefore, these hydrosols are considered natural food and/or feed additives to improve the gut health of humans and animals.

Key words: Gut health, pathogenic bacteria, food and/or feed additives, spices, herbs, medicinal value.