Garlic's Germ-killing Properties

Garlic's use as a medicine dates back thousands of years and is mentioned in medical texts from Greece, Rome, China and India. Garlic offers germ-killing benefits against a variety of pathogens, including bacteria, viruses, molds and parasites. Its antioxidant and other active components also demonstrate a positive effect on the cardiovascular system. Possible immune-enhancing properties of garlic that may help prevent some forms of cancer are being explored by researchers as well.

Food Preservative

Garlic is an effective food preservative for salad dressings and ketchup, according to the book "Food Flavors: Formation, Analysis, and Packaging Influences," edited by Ellene Tratras Contis. Garlic inhibited several species of bacteria and molds that commonly contaminate foods and was more effective than horseradish, which was also evaluated in the study. Additionally, garlic is effective at doses that do not undesirably alter the flavors of these foods.

Processing

The drying process may affect the germ-killing properties of garlic's active ingredient, allicin, according to A. S. Naidu, editor of the book, "Natural Food Antimicrobial Systems." Commercial preparations of garlic, such as peeled garlic and garlic oils, can be contaminated by Clostridium botulinum, the bacteria that causes botulism. When processed safely, however, garlic provides both germ-killing and germ-inhibiting effects. Fresh garlic exhibits the greatest antimicrobial properties. Naidu advises standardization of the purification and quality control techniques used in processing garlic to ensure the highest degree of safety and effectiveness.

E. coli

Garlic has been found effective against E. coli and Bacillus cereus -- a soil-dwelling bacteria that causes food poisoning, according to Victoria Renoux, author of the book, "For the Love of Garlic." Allicin extract has shown antibacterial activity against some drug-resistant strains of E. coli, Candida albicans and some types of intestinal parasites, such as Entamoeba histolytica and Giardia lamblia. Garlic may also have antiviral activity. Fresh is best, says Renoux, though freeze-dried garlic-juice powder is also effective against some bacteria. Garlic also provides high levels of the antioxidant vitamins C, E and beta-carotene and the antioxidant and immune-boosting mineral selenium.

Anti-viral

A derivitive of garlic known as allitridin inhibited cytomegalovirus, a type of herpes virus, in a study conducted at the Laboratory of Pediatric Clinical Virology, Department of Pediatrics, Tongji Medical College, China. In the test tube study, allitridin inhibited the virus in the early stages of replication. The study was published in the October 2006 issue of the journal "Antiviral Research."

Oral Health

Garlic may be good for your oral health, according to researchers at the Department of Oral Pathology, School of Clinical Dentistry, University of Sheffield, United Kingdom. In their study, they demonstrated antibacterial properties of garlic against several oral pathogenic bacteria, including Streptococcus mutans and P. gingivalis. The study appeared in the July 2005 issue of the journal "Archives of Oral Biology."