Preservatives (page 3)
Get the Facts
- The U.S. Food and Drug Administration (FDA) regulates the use of food additives. Nitrates and nitrites are used as preservatives for meat; they also give meat a healthy-looking red color. These preservatives are potentially dangerous because they can lead to the production of cancer-causing chemicals in the digestive system. FDA regulations allow foods to contain up to 500 parts per million (ppm) of nitrate and 200 ppm of nitrite. It is considered safe for adults to consume these preservatives at this low level, but foods for babies under one year of age should contain no nitrate or nitrite additives. Find out more about nitrates and nitrites. Could other safer methods of preserving meats be used?
- The food additive sodium benzoate is on the GRAS list. This chemical occurs naturally (in very small amounts) in many foods, such as prunes and cranberries. It is naturally present and part of the metabolic process in the human body. Find out more about sodium benzoate. What conditions must exist for it to be effective? List foods it is used in. What is considered a harmless level for human consumption?
- The FDA allows preservatives to be added to foods at specific levels. How are these safe levels of consumption determined?
- Five types of microorganisms that cause food to spoil are staphylococci, bacilli, molds, streptococci, and yeasts. These organisms feed on much the same substances as do humans and, when present, can bring about undesirable chemical and physical changes in food. With the right conditions, they can double in number every 20 or 30 minutes. Find out more about these food spoilers and how they can be controlled. You could prepare a data table for display showing diagrams of the five types of microorganisms and listing specific types of food spoilage, such as botulism (one of the most serious types of food poisoning) or simple fermentation by yeast. (See the sample data table in Figure 23.2.)
- Find out more about advancements in preserving foods. Compare home food preservation methods in the past and at present. Some things have changed very little, such as the smoking of meats on an open fire. You could use diagrams to compare old and new techniques.
- In the late eighteenth century, Napoleon offered 12,000 francs for a new way of preserving food. Nicolas Appert, a Parisian chef, won the money with his heat-preserved foods. Find out how this man without any knowledge of microbes and their role in food spoilage was able to preserve food.
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