How Do Food Preservatives

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How do Food Preservatives affect the growth of Microorganism?| By: Aya Zbedah|
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December 15, 2008|
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Mrs. Hafell 5th Period Biology|
2008-2009|
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Abstract

How Food Preservatives affect the growth of Microorganisms?
Aya Zbedah
Ballard High School

The purpose of this project is to see which preservative will either slow down the growth of bacteria or speed up the growth using the three most common preservatives: sugar, salt and, vinegar.

Humans usually have a problem keeping their food safe and clean at the same time to prevent from getting sick. But what they don’t know is that the way they preserve their food can be very dangerous.

Since the drying effect of salt has been used for thousands of years, it usually takes about 20% of salt to inhibit microbes. However, there are some microbes that can survive high salt concentrations. Sugar has the same mechanism as salt, but it takes much more sugar than salt to produce the same effect. So, if salt, sugar, and vinegar all have the same amount to test for the growth of bacteria, the sugar will speed up the growth of the bacteria, and the vinegar and salt will kill the bacteria.

Table of Contents

1. Problem/Purpose/Hypothesis……………… ……Page 4 2. Background Paper…………………………………………Page 5 3. Materials/Procedure………………………………… Page 10 4. Results……………………………………………………..Page 12 5. Conclusion…………………………………………….. Page 13 6. Bibliography………………………………………… Page 14 7. Tables and Graphs…………………………… Page 15-17

Problem/Purpose

The purpose to this experiment was to see which preservative was better at keeping the growth of bacteria at a minimum. This experiment would help out a lot of people because it allows them to see what preservatives they’re using are safe for their foods and themselves.

Hypothesis

If all living organisms require and are highly dependent on water to survive then adding salt will cause the water to osmotically diffuse out of the cell thereby killing cells in the bacteria. Then, sugar would help the bacteria in making more bacteria and vinegar will keep it neutral.

Background Paper

How does food get contaminated? The problem of protecting food from being spoiled has allowed scientists to understand ways on how we can try to prevent from getting foodborne illnesses. Thousands of types of bacteria are naturally present in our environment. Not all bacteria cause disease in humans. For example, some bacteria are used beneficially in making cheese and yogurt. Bacteria that cause disease are called “pathogens.” When certain pathogens enter the food supply, they can cause food-borne illness. Only a few types cause millions of cases of food-borne illness each year. Ironically, most cases of food-borne illness can be prevented. Proper cooking or processing of food destroys bacteria. They can grow in just about any food, but are fond of protein foods, such as meat, poultry, seafood, eggs, and dairy products in particular, as well as high-protein vegetables such as beans and grains. Food spoilage can be caused by a combination of various factors such as light, oxygen, heat, humidity, and all kinds of microorganisms. To prevent this, every food should be stored in a dark, dry place at a proper temperature. There are a few ways to protect your food from spoilage: 1) Avoiding light- photo resistant packages, dark bottles for oil 2) Oxygen- can foods, vacuum packaging

3) Heat- cooling
4) Humidity- vacuum packaging
5) The Development of Microorganisms- pasteurization, UHT( Ultra High Temperature), freezing, chemical preservatives, irradiation Germs can sometimes get into food through slaughter and meat processing procedures or through water containing waste and sewage. Food handlers can also contaminate food. If you leave food on the counter at room temperature then the bacteria will start to spread quickly. Bacteria such as E.coli and Salmonella cause most cases of food borne...
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