Example research essay topic: Using Irradiation To Make Food Safer For Consumers - 1,171 words

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Using Irradiation to Make Food Safer for Consumers In the world today, there is a limited access to fresh and uncontaminated food. Gunjan Sign, of Popular Science, reports that "The U. S. Centers of Disease Control estimates 6. 5 million confirmed cases and more than 25 million additional unreported incidents of food poisoning each year" (65). For example, with seventy-five percent of the chicken in Europe and sixty percent of the chicken in the United States infected, salmonella is a serious problem ("Food Irradiation").

The United States reports about two million cases of salmonella per year, costing an estimated 2. 44 billion dollars. "All creatures carry thousands of different bacteria in their bodies, yet most of these microbes are harmless or even beneficial, " says Sinha (65). Unfortunately, there are still many bacteria that cause problems for humans. For example, E. coli is usually found in the gut of cows. Although most people do not eat this part of the cow, the beef may sometimes be cross-contaminated if the intestines are accidentally split during slaughter. Steps are needed to minimize the risk of food contamination on the world's population.

Irradiation should be used to kill pathogens and extend the shelf life of food. After decades of exhaustive studies, experts agree that irradiation is safe and effective against food-borne pathogens. When irradiation is mentioned, many people think of nuclear radiation and then of Hiroshima and Nagasaki, or of Three Mile Island. "Do you want your food nuked?" inquire the opponents of irradiation (Satin 1 - 2). "Irradiation can be portrayed by anti-nuclear (sic) fanatics as something only welcome if you like chickens that come with three drumsticks, or turkey tetrazzini that glows in the dark, " says Stephen Chapman of the Chicago Tribune (3). The proponents of irradiation blame this fear on nothing more than the name, which has lead to the common misconception and association with nuclear radioactivity. Irradiation is correctly called "ionizing" in France, to avoid association with the negative meaning of the root word, radiation (Satin 3). This is not twisting it around, but simply giving another name to the same process.

Irradiation is simply the process of exposing food or some other substance to low levels of radiation. Irradiation does not make food radioactive, and it does not make it glow. In fact, every time one goes outside, one is being irradiated by the sun. If sun lotion was called "radiation protection cream or irradiation lotion, " people would be turned off at first (Satin 4). People would eventually realize that there was nothing to fear and would use it.

Radiation is thought by most people only to be present in nuclear bombs and power plants. Radiation, from Webster's New Collegiate Dictionary, is the process of emitting radiant energy in the form of waves or particles ("radiation"). This includes all energy in the electromagnetic spectrum. Light rays, radio waves, microwaves, and heat are all forms of radiation, and we do not fear them.

In fact, microwave ovens use radiation and are present in almost every American household. They were at one time feared, as irradiation is now. People eventually began to accept them for their efficiency and convenience. Irradiation works to disable cells by making changes to their DNA or RNA (nucleic acids). The gamma radiation used in irradiation makes changes to these highly complex macromolecules. The change is just enough to render them inoperable.

Irradiation kills food pathogens, insects, and other pests. Complete sterilization can also be achieved by the use of irradiation. Salmonella, listeria, and campylobacter can be killed or greatly reduced ("Food Irradiation"). Irradiation can delay ripening and spoilage of produce.

For example, potatoes often ripen in storage, due to the change of starches into glucose, and become mushy. Irradiation disables the macromolecules responsible for this change. Precooking the potatoes has the same effect but is not practical (Satin 13). One of the concerns about irradiation is the formation of free radicals.

These free radicals, or electrically charged particles, are formed during the process of irradiation. Free radicals are slightly unstable and try to find another compatible free radical to link to, forming a stable radio lytic compound. This happens faster in moist than in dry foods. This is because the free radicals are more free to move in liquids than in solids. These radio lytic compounds and free radicals may sound scary to many people when they are taken out of context. However, these compounds are very common, and they are formed during everyday events such as metabolism and other simple biochemical reactions (Satin 18).

Gamma radiation can be used to irradiate food. This requires an unstable isotope which slowly decays and emits gamma radiation. One such isotope is Uranium- 238. Although it is not used in irradiation, it is commonly used as an example to show how gamma radiation is emitted. Uranium- 238 is very unstable and can hardly hold itself together. Eventually, a particle made of protons and neutrons breaks free from the atom forming a new atom, thorium- 234.

The process continues, changing into protactinium- 234, and eventually into lead- 206. Occasionally during the remainder of the decay, non-particle radiation is released in the form of gamma (y) radiation. Gamma radiation is the form of nuclear radiation that is used in food irradiation. Gamma rays (as previously mentioned) are used in one type of irradiation plant, the gamma ray type facilities. The most common radioactive substance used in this process is cobalt- 60, but cesium- 137 is also used. Pellets of the cobalt- 60 are stored in stainless steel cylinders called pencils.

Each pencil is about 17. 75 inches long and one half inch in diameter (Murano 11 - 12). The pencils are transported to the facility in a lead cast to prevent contamination of people or other things during transfer. The cobalt- 60 pencils are held on a source rack. Since most products must be exposed to the gamma rays for several hours, a conveyed moves the food past the source rack, stops, and then moves again.

The cobalt- 60 emits gamma rays continuously in all directions. A conveyed loops all the way around the source rack to take advantage of the gamma rays being emitted in all directions and to maximize efficiency. A standard gamma ray facility contains about one million curies (Murano 11 - 12). The curie is "a unit of radioactivity equal to 3. 7 1010 disintegration's per second" (Webster's "curie").

When new, each pencil contains about six-thousand to thirteen-thousand curies. Electron beam facilities are the second type of irradiation plants. These plants do not use atomic radiation, but rather, an electron beam generator and require extensive electrical components and heat exchangers to cool them. The plants usually use an electron beam of five to ten million electron volts (Murano 15 - 16).

However, a five megavolt beam from both sides of the food can only penetrate one and one half inches. The throughput is determined by the number of watts. Since the beam is directed at...

Research essay sample on Using Irradiation To Make Food Safer For Consumers