Food Spoilage: Refrigeration & stomach cancer
HEALTH & FITNESS By KEMI ILORI
Tuesday, November 25, 2008

It may surprise you to know that the first practical application of refrigeration, was a health based one and it served the basis of the fridges that we all use today. This will become evident as you read on. Last week, I drew attention to the fact that spoilt food could be the source of deadly diseases. It is always prudent to throw away food that is spoilt. No matter how tempted we are to eat the food. The stomach is the receptacle for the food that we eat after we have swallowed the food. The stomach is a J-shaped organ that lies in the left and central portion of the abdomen.

The stomach produces many digestive juices and acids that mix with food and aid in the process of digestion. One of the greatest inventions of our time is refrigeration. It has helped to reduce the incidence of stomach cancer from food from two important areas. Stomach cancer (also known as gastric cancer) is a disease in which the cells forming the inner lining of the stomach become abnormal and start to divide uncontrollably, forming a mass called a tumor.

While the exact cause for stomach cancer has not been identified, several potential factors that have been associated with it include; diet, work environment, exposure to the bacterium Helicobacter pylori. Before the invention of refrigeration, the method of food preservation that was used was drying, salting, smoking, pickling of food etc. Some of these methods still made the food liable to spoilage from spores, bacteria, fungi. But these foods often also contained large amounts of nitrites and nitrates, which can be converted in your stomach into cancer-causing compounds. Countries where consumption of salted meat and fish and pickled vegetables is high e.g.

Japan and Korea are notable examples and they tend to have correspondingly high rates of stomach cancer. Eating a diet high in red meat, especially when the meat is barbecued or well done, also has been linked to stomach cancer. Refrigeration reduces the need to use these preservation methods and will keep food fresh for a few days. This is except, of course, if you have a particular liking for such foods (pickled, nitrate preserved) and you choose to eat them regularly as a matter of choice.

These are found in processed foods. Fresh unwashed, unpeeled, untrimmed and uncooked food have a high bacteria load. When food is kept in fridges, the temperature of the food is lowered and this helps to prevent the food from spoiling. This is because refrigerating food slows or stops bacterial growth in food that would have led to spoilage. At 320F, most bacteria are unable to grow, but still survive. This means that your food should not stay in the fridge for long. If you leave food in the fridge for long enough, bacteria will start growing in them. Unpreserved food should stay in the fridge for less than a week. Freezing is able to preserve food for longer. Stomach cancer is one of the leading causes of cancer deaths in several areas of the world, most notably Japan and other Asian countries. In Japan, it appears almost ten times as frequently as in the United States.

The number of new stomach cancer cases is decreasing in some areas, however, especially in developed countries; this is good news for us! In the United States, incidence rates have dropped from 30 individuals per 100,000 in the 1930s, to only 8 in 100,000 individuals developing stomach cancer by the 1980s. The use of refrigerated foods and increased consumption of fresh fruits and vegetables, instead of preserved foods with high salt content, may be a reason for the decline.
The invention of refrigeration is particularly useful to us in the tropical regions where the ambient temperature makes our foods more prone to spoilage.

The first known method of artificial refrigeration was demonstrated by William Cullen at the University of Glasgow in Scotland in 1748. Cullen used a pump to create a partial vacuum over a container of diethyl ether, which then boiled, absorbing heat from the surrounding air. The experiment even created a small amount of ice, but had no practical application at that time. Refrigeration is the process of removing heat from an enclosed space, or from a substance, to lower its temperature. A refrigerator uses the evaporation of a `liquid to absorb heat.

The liquid is called the refrigerant, and when used in a refrigerator; it evaporates at an extremely low temperature, creating freezing temperatures inside the refrigerator. It seems quite easy now, but it took a while to develop.
In 1805, an American inventor, Oliver Evans, designed the first refrigeration machine. The first practical refrigerating machine was built by Jacob Perkins in 1834; it used ether in a vapor compression cycle.

An American physician, John Gorrie, built a refrigerator based on Oliver Evans' design in 1844 to make ice to cool the air for his yellow fever patients; this was the first practical application that I referred to earlier. Since these humble beginnings, refrigeration has gone through various modifications till the refrigerator and other appliances that use the refrigeration principle emerged.
The first refrigerator was developed in 1918 by a man called Kelvinator in the United States of America. The Kelvinator brand still exists today. It was not until around 1921, that production started on a commercial scale, even then, only about 5,000 people had fridges in the whole world! However, Europe lagged behind America. By 1937, nearly half of all Americans had a refrigerator while only 12 per cent of British homes had refrigerators by 1958. Most homes in urban Nigeria have a fridge.

We all know that the best option is farm fresh food, cooked and straight to the table, but that is impossible for most of us. Refrigeration helps to keep our food available for longer, but more importantly, it is one appliance that has be recognized globally for helping to reduce the incidence of stomach cancer. It seems like a fridge is almost indispensable to the average home. When purchasing a fridge, it is advisable that you buy one that says No CFCs on it. You should always remember that you should not leave your food in the fridge for too long. Some microbes grow in the fridge! Foods also lose some of their nutrients as they stay in the fridge. Consume refrigerated food in less than a week.