Why Food Spoils Science Project
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Written by Dee
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Saturday, 07 July 2007 |
Why Food Spoils Science Project. Learn how bacteria cause food to go bad. Science teachers can also use this as a bacteria or prokaryote lesson plan or exercise.
Keeping Foods from Spoiling Science Project
You know that many foods if left in the air spoil or decay. Name some foods which you know will spoil if left exposed
to the air. Since foods must be transported long distances and frequently must be kept many months before being used,
the problem of preserving foods is of the very greatest importance. Without the means of preserving food from
decay our present civilization could not have arisen. Think for a moment of the possibility of the existence of great cities, like New York, Chicago, or of great manu-
facturing centers, if ways of keeping foods from spoiling had not been discovered. Could the United States have sent
her great army of 2,000,000 men to Europe, if there had been no means of preserving foods for many months and
even years? In considering how foods may be kept from spoiling, naturally the first problem is Science Fair Project Idea 1: What causes foods to spoil or decay? Is it the oxygen of the air acting upon the food which causes the change, a process of slow oxidation such as we have
observed in a number of cases? The question can be answered by performing the following experiment. Food Decay Science Experiment To find out what causes foods to spoil when left exposed to the air, pour some beef tea made of beef extract and a
small amount of peptone (digested protein) into two test tubes. Boil the beef tea in each test tube for an equal length of time. Stopper one with cotton. Allow the other to remain open. Place the tubes side by side in the room. (Experiments have proved that air will pass through a cotton stopper but that particles floating in the air are caught by the cotton.)
After a few days observe the contents of the tubes. What differences in appearance are noticeable? Smell the con-
tents of each tube. What is your conclusion? Is oxygen alone able to cause substances to decay? If a drop of the
beef tea from the unstoppered tube is examined with a high power microscope, a very large number of exceedingly
small objects will be seen. Some are spherical and some are rod-shaped.
If even the smallest possible amount of the spoiled beef tea is added to the unspoiled, stoppered tea, the latter also be-
comes spoiled in a few days. Another examination of the tea with the microscope will show that there has been an
enormous increase in the number of the spherical and rod-shaped bodies. The fact that they have increased in number
is an indication that they are living bodies. These small, living bodies are called bacteria.
It seems evident that the spoiling of the beef tea was associated with the development of bacteria within it.
Many experiments have shown that the decay of plant and animal (organic) matter is always brought about by bacteria
or their close relatives, the molds.
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Last Updated ( Sunday, 22 July 2007 )
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