Sophia Marie D. Verdeflor Grade 9-1 STEP August 18, 2014

Assignment in Consumer Chemistry

Food Irradiation

Food irradiation is the process of exposing foodstuffs to a source of energy capable of stripping electrons from individual atoms in the targeted material (ionizing radiation). The radiation can be emitted by a radioactive substance or generated electrically. This treatment is used to preserve food, reduce the risk of food borne illness, prevent the spread of invasive pests, delay or eliminate sprouting or ripening, increase juice yield, and improve re-hydration. It is permitted by over 50 countries, with 500,000 metric tons of foodstuffs annually processed worldwide. Food irradiation is criticized because irradiation can initiate chemical changes are different than those that occur when heating food (Unique Radiolytic Products). Some people worry that there is the potential of danger from these substances. Research has discovered that one family of chemical is uniquely formed by irradiation, and this product is nontoxic. When heating food, all other chemicals occur in a lower or comparable frequency. Others criticize irradiation because of confusion with radioactive contamination or because of negative impressions of the nuclear industry. The regulations that dictate how food is to be irradiated, as well as the food allowed to be irradiated, vary greatly from country to country. In Austria, Germany, and many other countries of the European Union only dried herbs, spices, and seasonings can be processed with irradiation and only at a specific dose, while in Brazil all foods are allowed at any dose. Irradiation is also used for non-food applications, such as medical devices, plastics, tubes for gas pipelines, hoses for floor heating, shrink-foils for food packaging, automobile parts, wires and cables (isolation), tires, and even gemstones. Uses

Irradiation is used to reduce pathogens, increase shelf life, eliminate pests, increase juice yield, delay

sprouting, and improve re-hydration.

Irradiation is used to reduce the pathogens in foods. Depending on the dose, some or all of

the microorganisms, bacteria (as well as "good bacteria" that inhibit the growth of pathogenic bacteria),

and viruses present are destroyed, slowed down, or rendered incapable of reproduction. This reduces or

eliminates the risk of food borne illnesses. Some foods are irradiated at sufficient doses to ensure that

the product is sterilized and does not add any spoilage or pathogenic microorganisms into the final

product.

Irradiation is used to as delay the ripening of fruits and the sprouting of vegetables by slowing down the

enzymatic action in foods.

Impact of irradiation on food chemistry

The irradiation source supplies energetic particles or waves. As these waves/particles pass through a

target material they collide with particles. Around the sites of these collisions chemical bonds are

broken, creating short lived radicals (e.g. the Hydroxyl radical, the hydrogen atom and solvated

electrons). These radicals cause further chemical changes by bonding with and or striping particles from

nearby molecules. When collisions damage DNA or RNA, effective reproduction becomes unlikely; also

when collisions occur in cells, cell division is often suppressed.

Irradiated food does not become radioactive as the radioactive source is never in contact with the foodstuffs and energy of radiation is limited below the threshold of induction of radioactivity, but it does reduce the nutritional content and change the flavor (much like cooking), produce radiolytic products, and increase the number of free radicals in the food.

Irradiation causes a multitude of chemical changes. The scale of these chemical changes caused by

irradiation is not unique. Cooking, smoking, salting, and other less novel techniques, cause the food to

be altered so drastically that its original nature is almost unrecognizable, and must be called by a

different name. Storage of food also causes dramatic chemical changes, ones that eventually lead to

deterioration and spoilage.

Public perception and impact

Irradiation has been approved by the FDA for over 50 years, but the only major growth areas for the commercial sale of irradiated foods for human consumption are fruits and vegetables that are irradiated to kill insects for the purpose of quarantine. In the early 2000s in the US irradiated meat was common at some grocery stores, but because of lack of consumer demand it is no longer common. Because consumer demand for irradiated food is low, reducing the spoilage between manufacture and consumer purchase and reducing the risk of food borne illness is currently not sufficient incentive for most manufactures to supplement their process with irradiation. It is widely believed that consumer perception of foods treated with irradiation is more negative than those processed by other means, although some industry studies indicate the number of consumers concerned about the safety of irradiated food has decreased in the last 10 years to levels comparable to those of people concerned about food additives and preservatives. “These irradiated foods are not less safe than others,” Dr. Tarantino said, “and the doses are effective in reducing the level of disease -causing micro-organisms.” "People think the product is radioactive," said Harlan Clemmons, president of Sadex, a food irradiation company based in Sioux City, Iowa. Some common concerns about food irradiation include the impact of irradiation on food chemistry, as well as the indirect effects of irradiation becoming a prevalent in the food handling process. Irradiation reduces the risk of infection and spoilage, does not make food radioactive, and the food is shown to be safe, but it does cause chemical reactions that alter the food and therefore alters the chemical makeup, nutritional content, and the sensory qualities of the food. The some of the potential secondary impacts of irradiation are hypothetical, while others are demonstrated. These effects include impacts due to the reduction of food quality, the loss of bacteria, and the irradiation process. Because of these concerns and the increased cost of irritated foods, there is not a widespread public demand for the irradiation of foods for human consumption.