Chives inhibit E. coli O157:H7, Salmonella in culture medium.

E. coli O157: H7 and Salmonella are two pathogens of concern. One approach used to inhibit or inactivate these pathogenic bacteria involves the use of natural antibacterial preservatives. Although numerous studies have been published on the antimicrobial activity of spices, few have reported data related to the antimicrobial activity of chives.

The objective of scientists at North Carolina State University was to examine the antibacterial activity of chives against several strains of E. coli O157:H7 and Salmonella. Researchers used six strains of E. coli O157:H7 and 38 strains of Salmonella in this study.

Chives were cut into small pieces, blended and centrifuged to obtain a chive extract. Researchers used a diffusion assay to determine the antibacterial activity of the extract. The extract had strong antibacterial activity against all tested strains of bacteria.

The minimum inhibitory concentration of the extract was 200 [micro]l to 300 [micro]l, and its minimum lethal inhibition was 0.06 to 0.08 (vol/vol). Researchers found that at least 800 [micro]l were required to completely inhibit bacterial growth during a 24-hour period. A heat treatment at 60 C for 20 minutes, or at 90 C for 5 minutes, had little effect on the activity of chive extract. But a heat treatment at 121 C for 30 minutes completely inactivated the action of the extract. Still, the extract proved effective against the strains and has potential for inhibiting pathogens in food systems.

Chives also offer some nutritious benefits. The medical properties of chives are similar to those of garlic, although weaker. The less potent effects in comparison with garlic are probably the main reason for its limited use as a medicinal herb. Containing numerous organisulphide compounds, such as allyl sulfides and alkyl sulfoxides, chives have a beneficial effect on the circulatory system, acting upon it by lowering blood pressure. As chives are usually served in small amounts and never as the main dish, negative side effects are rarely encountered, although digestive problems may occur if too much is consumed. Chives are also rich in vitamins A and C, as well as trace amounts of sulfur and iron.

Further information. Salam Ibrahim, School of griculture and Environmental Sciences, North Carolina A & T State University, Food Microbiology and Safety Laboratory, Greensboro, NC 27411; phone: [phone]; fax: [phone]; email: [e-mail].