I recommend this short, interesting article.
Garlic, onion, allspice and oregano, for example, were found to be the best all-around bacteria killers (they kill everything), followed by thyme, cinnamon, tarragon and cumin (any of which kill up to 80 percent of bacteria). Capsicums, including chilies and other hot peppers, are in the middle of the antimicrobial pack (killing or inhibiting up to 75 percent of bacteria), while pepper of the white or black variety inhibits 25 percent of bacteria, as do ginger, anise seed, celery seed and the juices of lemons and limes.
The Cornell researchers report in the article, “Countries with hotter climates used spices more frequently than countries with cooler climates. …”