SARAH LONG:And this is Sarah Long with the VOA Special English program SCIENCE IN THE NEWS.
Today,we tell about spices and some interesting ideas about these substances.
BOB DOUGHTY:People have used spices in food for thousands of years.
Some spices are valued for their sharp taste.Others are chosen for their smell.
Spices are made from plants or vegetables.Common spices include pepper,cloves,ginger,mustard,cinnamon and dill.
Spices come from different parts of plants.
For example,cinnamon comes from the hard outer covering of cinnamon plants.
The spice ginger comes from the part of the ginger plant that grows underground.
Spice plants grow in many countries.
The Molucca islands in Indonesia,for example,are famous for producing spices such as cloves,nutmeg or mace.
Vanilla comes from plants growing in south America.
Many people grow spice plants outside their homes.
Then they dry the plants for later use.
Some common spice plants can even be grown inside a house if they are placed in sunny areas near windows.
SARAH LONG:Spices have influenced world history.
For example,the Goth people of Europe defeated Roman forces in a battle almost two-thousand years ago.
After the fighting ended,the leader of the Goths is said to have demanded five-thousand pounds of gold and three thousand pounds of pepper.
Later,explorers like Marco Polo,Vasco de Gama and Christopher Columbus discovered new lands while seeking to expand trade with spice-growing areas in Asia.
The Italian cities of Genoa and Venice became powerful because they were at the center of this spice trade.
The spice trade was so important to national economies that rulers started wars in their struggle to control spices.
BOB DOUGHTY:Spices are commonly used because they can make food taste better.
Two researchers at Cornell University in the American state of New York say there is another reason for spice use in cooking.
They say spices contain substances that kill or slow the growth of dangerous bacteria in food.
It is a known fact that some spices destroy bacteria.
Spices long have been used to keep food safe to eat.
In the past,spices also were used to help protect the condition of dead bodies.
The study reportedly was the first to investigate the idea that spices are used in cooking because they destroy dangerous bacteria.
SARAH LONG:Researchers Paul Sherman and Jennifer Billing examined more than four-thousand-five-hundred directions for cooking meat or fish.
They found these recipes in traditional cookbooks published in thirty-six countries around the world.
The two researchers studied the spices used in the recipes and tested them against thirty kinds of bacteria.
The researchers say people use spices because they make food taste good,and bacause spices protect people against disease.
They say people who used spices many years ago lived healthier and longer lives because the spices killed disease-causing bacteria in their food.
They say the use of the spices spread in some areas because the people who used spices shared these safer cooking methods with their children and friends.
BOB DOUGHTY:Professor Sherman and Mizz Billing found that onion and garlic are used most often in areas where weather conditions are very warm.
These two spices stopped almost one-hundred percent of the bacteria against which they were tested.
Hot peppers stopped the growth of eighty percent of the bacteria tested.
The researchers found that foods from warm climates contain more onion,garlic and hot peppers than foods from other areas.
For example,eighty percent of the recipes from Indonesia called for garlic and onion.
Seventy-seven percent called for the use of hot peppers.
But the use of spices was not as common in cooler climates.
Onions appeared in fifty-six percent of the recipes from Ireland.
Garlic was called for in twenty-three percent of the Irish recipes,and hot peppers in only two percent.
In Norway,no recipes called for garlic and only twenty percent called for onions.
SARAH LONG:The Cornell University researchers found that countries with warm climates generally use many different spices in many of their foods.
Countries with cooler climates use fewer spices in fewer foods.
The researchers also found that spice use within large countries sometimes differed from one area to the next.
Examples include the northern and southern United States,and northeastern and southwestern China.
The study showed that the recipes from warmer areas used more spices than the recipies from cooler areas.
These findings support the idea that the most effective spices are used mostly in areas where bacteria destroys foods quickly.
Such areas generally are very warm.
BOB DOUGHTY:Professor Sherman and Mizz Billing rejected other attempts to explain the large amount of spices in foods from,warmer climates.
One possible explanation is that people in warm climates use more spices because spices cause their bodies to release sweat.
It says the liquid from sweat may help to cool the skin.
The researchers say that only one spice they studied,hot peppers,can cause sweating.
Ant it is not one of the most popularly used spices.
The researchers also note that hot pepper do not produce sweating in all people who eat them.
SARAH LONG:Another explanation for the use of spices is that they hide the bad smell and taste of food already being destroyed by bacteria.
The researchers rejected this idea.
They say people who eat food with harmful bacteria would be more likely to get sick and die,so this method of cooking would not be passed on to others.
A third explanetion for the increased use of spices in warmer climates is that people use spice plants growing near them.
The study found that people do not use every spice grown in their local area.
And,they do use many spices imported from other countries.
For example,pepper is used in all thirty-six countries in the study,but it grows in only nine of them.
BOB DOUGHTY:The American researchers say the smells and taste of spice plants probably have changed over time to protect the plants against bacteria,insects,and fungi.
They say this is important because humans are affected by many of these same enemies.
The bacteria and fungi that live on and inside dead plants can be harmful to humans.
If spices kill such substances or stop their poisons,spice use might reduce the likelihood of developing food poisoning or other sicknesses.
SARAH LONG:Not everyone agrees with some of the study findings.
Critics argue that economic and cultural forces can explain spice use in many countries.
Frederick Simoons is a retired American expert of world cultures.
He says people very often explain things from the past in terms of modern knowledge.
Mister Simoons notes that garlic was often banned for religious leaders because garlic has a strong smel
He said such smells were not permitted in ancient times for people wishing to communicate with spiritual being
BOB DOUGHTY:One interesting finding discussed by the Cornell researchers is the rate of food poisoning in Japan and Korea.
Food poisoning affected about thirty of every one-hundred-thousand Japanses from Nineteen-Seventy-One until Nineteen-Ninety.
But only three of every one-hundred-thousand Koreans had the problem during the same period.
The researchers were surprised by this because both countries have similar climates.
They noted,however,that Korean food is spicier than Japanese.
They say Korean food also calls for more spices known to have anti-bacterial effects.
The researchers do not know why Japanese recipes do not call for the more effective spices.
But they say the spices used in Japanese cooking may have been enough to protect people from sickness in the past,but not now.