ECOLOGY AND THE CONSERVATION OF NATURAL RESOURCES
|Science in Society
||Societal Needs 4.4a
To develop an understanding of the interdependence of all organisms and the need for conserving natural resources
Awareness of, concern for, and action on problems in the environment can result in major improvements.
Ecology Q4.00 To understand how intentional and unintentional food contamination can occur through man's activities
INSTRUCTIONAL OBJECTIVES: The learner will:
4.01 explain the importance of side effects of materials unintentionally added to plant or animal material which is to be consumed as food or to be added to the food chain.
OUTLINE OF CONTENT:
4.02 explain the importance of knowing how to appropriately dispose of and/or use materials which could be hazardous to living things if allowed to enter the food chain.
4.03 explain the importance of side effects of materials intentionally added to plant or animal material which is to be consumed as food or to be added to the food chain.
4.04 describe the dangers of sulfites, nitrates, and sugar as food additives, and the role of government agencies that regulate their use.
4.05 trace the presence of DDT in the food chain that results in the endangerment of a species.
I. Food contamination
A. Intentionally added
II. Disposal and/or use of hazardous materials
B. Unintentionally added
III. DDT in food chains
B. Industrial chemicals
C. Other chemicals
A. DDT on crops -- insects/mice -- bald eagles
IV. Food additives
B. DDT in water -- plankton - small fish -- larger fish, brown bear
V. Government agencies regulating environmental health
A. Food and Drug Administration -- all foods shipped interstate except red meats, poultry, and eggs.
B. Food Safety and Quality Service -- red meats, poultry, and eggs.
C. U.S. Dept. of Agriculture - pesticides
D. Environmental Protection Agency - toxic chemicals in the environment that might get into the food chain
2. citizen participation
COMPONENT OF SCIENCE: Science in Society
To enable students to demonstrate positive attitudes toward science in solving problems and making personal decisions about issues affecting the individual, society and the environment.
4.4 SOCIETAL NEEDS - Science establishes the basis for applying technology to needs within a society.
4.4a - Scientific research and development have an ethical component.
BENCHMARK: Scientists consider the effect of research and development.
Three 55-minute class periods
Magazines, newspaper articles, food labels, student activity sheets
AAT, additives, EPA, FDA, Food Safety and Quality Service, mutagens, nitrites, pesticide, residue, USDA, sulfites
Are there any of you who have a garden? Have you ever helped someone tend a garden? What are some of the problems you encounter? (weeds, bugs, preparing the food to keep it) What happens if you do not remove the insects or kill them? (they eat the plants) What do you know about food you buy in the grocery store? Do you know where it was grown? Do you know what chemicals were used an it? We are going to find the answers to these and other questions you have about food safety and contamination.
I asked each of you to bring a label from a can of food at your house. Do you understand the label? Do you know what is not on the label but may be added to the food?
A food additive is a substance or a mixture of substances, other than basic foodstuffs, present in food as a result of any aspect of production, processing, storage or packaging. The term does not include chance contaminants.
Food processors have an estimated 10,000 chemicals they can add to what we eat. Some are harmless, some are beneficial. Why are chemicals used in food processing? Remember I asked you how you prepare food from the garden? What is the reason to process the food? (so you can keep it and eat it at a later date) Food processors add these chemicals for one or more of the following purposes: Improve nutritional value, enhance quality or consumer acceptability, improve keeping, quality, make the food more readily available, and facilitate its preparation.
The majority of food additives have nothing to do with enhancing the nutritional value of food. Most of the chemicals make the customer want to buy the food. We want enhanced food because we see beautiful pictures of foods in our magazines and on television. We expect all of Mother Nature's products to be perfect and they are not. We dye the skins of oranges a bright orange to match our mental picture of the ideal orange. We feed chemicals to chickens to turn the skin yellower and make it look more appetizing. Fruits and vegetables are kept unblemished by fungicides, pesticides, herbicides, and other antispoilants.
Food purveyors are responding to our change in lifestyle. We want food that is easy to prepare and that means higher costs. Women who spend the day on the job do not have the time or energy to prepare a traditional meal. The traditional family sit-down dinner has been abandoned by many working families with different schedules.
Microwave ovens have become so popular that by 1990 it is predicted that 60 percent of American homes will have them.
Foods that are easier to prepare must be mashed, mushed, mangled, and loaded with chemicals so that we can have cake mixes, peeled, and sliced potatoes, and instant everything.
By law the label must identify the product in a language the consumer can understand. It must list the manufacturer, packer, or distributor, and declare the quantity of contents either in net weight or volume. Ingredients must be listed in the order of their predominance. Pictures of the produce placed on the label must be representative of the container's contents.
For more than 300 standard foods--including ice cream, catsup, any mayonnaise--no ingredients need be listed. Processors follow the standard chemical recipes written out by the government. The manufacturer may substitute a nonstandard chemical if he lists it on the label. If artificial coloring or) flavoring is listed, the processor does not have to identify what kind of flavorings or colorings are used.
The only time you can count on "light" foods having less calories is when the label has "low calorie" or "reduced calories" because the FDA requires such products to have at least 1/3 fewer calories than similar regular products.
Food companies test additives to be sure they will not harm you. Additives are fed to animals in large amounts at one time. Using control animals (animals not fed the additive) they perform autopsies to determine the effects on tissues or observe animals for symptoms of side effects.
There is a large percentage of food additives that have not been tested for long-term effects. Cancer may take 20 years to develop in humans and often more than 2 years in animals. One partial solution is to use the AWS TEST developed in the early 1970's. This simple test using common bacteria reveals whether a chemical changes genetic material.
Almost all chemicals that cause cancers have given positive results on this test.
Another great problem with testing additives is how they interact with each other and the 63,000 other chemicals in common use today. Animal studies have predicted several carcinogens including three that may be contaminants in food: the mold on nuts, alfatoxin, the plastic used in packaging, vinyl chloride, and the hormone used to increase the weight of meat.
The father of modern food additive laws was Dr. Harvey W. Wiley. In the 1900's he led the fight against boric acid, formaldehyde, and salicylic acid. Young men volunteered to be guinea pigs, which meant eating measured amounts of these chemicals to determine toxicity.
As a result of his work, the first Federal Food and Drug Act was passed in 1906. By 1958, the Food Additives Amendment was passed. Food and chemical manufacturers were required to run extensive tests on additives before they were marketed.
The food industry wants changes in food laws to protect them economically. They do not want recall of products but gradual phasing out so the food supply will not be disrupted or so economic hardships will not be placed on the companies.
Now that we have discussed the history of food additives, let's divide additives into broad categories for further study. Antispoilants are used to prevent microbes from spoiling food and chemical deterioration of food. There are about 100 in common use. These prevent foods from off-flavors and off-odors. Benzoic acid and BHA are two examples. Another type of preservative is a sequestering agent. These agents prevent physical and chemical changes that affect color, flavor, texture, or appearance. EDTA is an example.
Acids, Alkalis, Buffers and Neutralizers are used to modify the flavors in soft drinks. Phosphoric acid gives colas that tangy taste. Buffers and neutralizing agents control the acidity or alkalinity in food. Some common chemicals in this class are ammonium bicarbonate, calcium carbonate, and tartaric acid.
Humectants are necessary in the production of some types of confections and candy to prevent drying out. Substances used for this purpose include glycerine, which helps marshmallows retain their soft moist texture, propylene glycol, and sorbitol. Calcium silicate is used to prevent table salt from caking.
Coloring agents of both natural and synthetic origin play a major role in attractiveness of foods. In 1960, the FDA required manufacturers to retest all artificial colors to determine safety. At present, there are six permanently listed as safe. Among them FD and C Blue No. I and FD and C Green No. 33 have been shown to cause tumors at the site of injection in animals, but the FDA did not consider this significant because the experiments concerned injection by needle and not ingestion in food or application to the skin. Among the natural colors used in foods are alkanet, annato, carotene, chlorophyll, cochineal, saffron, and turmeric. Foods that are frequently colored include candy, baked goods, soft drinks, butter, cheese, and cream.
Flavoring agents are the most numerous additives, with over 2000 in use. Some 500 are natural and the balance synthetic. They are usually added in amounts from a few to 300 parts per million. Amyl acetate, benzaldehyde, carvone, ethyl acetate, ethyl butyrate and methyl salicylate are examples. The most common flavor enhancer is monosodium glutemate (MSG) and maltol.
Physiologic Activity Controls are added to fresh food to serve as ripeners or antimetabolic agents. Chemicals are added to make bananas ripen faster and prevent potatoes from sprouting. Various amylases from plant, animal, fungal, and bacterial sources have been used to break down the components of starches to make them more digestible. Enzymes are used in candy, the brewing industry, bread and frozen milk concentrates.
Sanitizing agents are used to clean bacteria and debris from products. Emulsifiers are added to maintain a mixture and assure consistency. They influence ease of mixing and smoothness such as whipped cream and frozen desserts. Some common emulsifiers are lecithin, the monoglycerides, and diglycerides, and propylene glycol alginate.
Enrichment of food means that the natural nutrients have been removed during processing and then replaced. Cereals are enriched to provide from 12 to 23 percent of the daily supply of thiamine, niacin, and iron.
A number of additional substances are used for various purposes. Sugar substitutes like saccharin and sorbitol are commonly used.
A Consumer's Dictionary_of Food Additives used as a source.
*Winter, Ruth. A Consumer's Dictionary of Food Additives used as a source.
In class, ask the students to make a list of preservatives and additives on the label of food they brought to class. Share labels with other students and find as man different additives as you can. Prepare a chart listing food additives, and purpose of additive.
1. Divide students into groups. Assign each group a certain type of additive. (preservatives, acids, alkalis, buffers, neutralizers, humectants, coloring agents, flavorings, physiologic activity controls, bleaching and maturing agents/break improvers, processing aids, and nutrition supplements.) Choose 10 food labels and find the additive you are studying. List the food and the additives.
2. Choose articles to read from list. Have a debate between farmers and grocery on use of pesticides.
3. Prepare a bibliography of articles on DDT and food chain.
4. Write a report an DDT - use old as well as current information.
5. Cut articles out of the newspaper that refer to the EPA and its work.
6. Prepare a file for your library on food additives.
With the cooperation of a grocery store, assign students different types of food to study. Have them complete the above activity at a grocery stores
Interview an organic gardener. Tape the interview and share with the class.
Now that we have completed our study of food additives, list some of the reasons we use additives. List some cautions we need to observe.
mutagens - change genetic material that is transferred to daughter cells when cell division occurs.
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