Chemical Food Preservatives - Essay Example

Chemical Food Preservatives Describe and discuss the desirable qualities of chemical food preservatives? The goal of food conservation is to keepthe food in a protected condition over a period of time so that it will not ruin the food or make people ill who consume it. The organisms that ruin food product are usually called spoilage organisms, whereas those that make people sick are referred to as pathogens. The methods used for food preservation varies and one among them is by using chemical. Many chemicals are used today in the preservation of foods and they vary from the simple substances like salt and sugar, to complex compounds such as benzoates. The important qualities of the chemical preservatives considered are mainly should maintain or improve nutritional value and preserve quality and freshness. The most common chemical preservatives used today and the chemicals those have the qualities GRAS (generally regarded as safe) are sulphites, dehydroacetic acid, sodium nitrite, ethyl formate, propionic acid, sorbic acid and benzoic acid. These substances are by now well thought-out harmless because of widespread use in the past with no known damaging effects. These chemicals have multifaceted mechanisms by which they restrain their target organisms (Davis and Conner, 2001). (4) 2. Describe two examples of chemical preservatives where one or more of these criteria are not met Sulphite compounds are preservatives which are used in such foods as soups, biscuits, dehydrated vegetables, fruit juices, jams, sauces, instant coffee, dried fruit, French fries, and many other products. Sulphur dioxide is antioxidants that are used to lighten and to stop browning in dried fruits and vegetables, fruit juices and alcoholic beverages. It avoids yeast growth and also inhibits bacteria growth in wine. Sulphites slow down microbial increase by reacting to the energy currency of the cell and it blocks the cellular transport system. This process changes the flavour and also reduces the levels of essential amino acids. Sulphites are found in dried fruits and vegetables, such a dried apricots, sun-dried tomatoes and dried sweet potatoes. Sulphites are also found in liquids such as vinegar, coconut syrup, lemon juice and fruit juices to extent their shelf life. Sulphurs are also used in the preparation of wines. Some people are sensitive to sulphites. Sulphites have been recognized to cause asthma and hyperactivity. They can also wipe out vitamins in the foods they preserve. Sulphites have been connected to a variety of illnesses such as asthma attacks, dizziness, nerve problems, blurred vision, stomach problems and other possible ailments. Studies have linked sulphites with the lessening of vitamin B1 or thiamine which can affect the nervous system. Some examples of sulphite preservatives are: Calcium hydrogen sulphite, Calcium sulphite, Potassium bisulphite, Potassium sulphite, Potassium sulphite, Sodium bisulphate, Sulphur dioxide etc. (Howley, 2001) 3. Describe three chemical food preservatives in detail. For each one, discuss: a. The type of chemical and mode of action b. What types of food they should be used for (any why) c. How much can be added, what governs this? Propionic acid and its salts, sodium and calcium propionates are accepted in the United States as GRAS (Generally Recognized As Safe) preservatives for food. Antimicrobial achievement of those substances is aimed at to molds and rope bacteria, with almost no effect on yeast, hence making them a perfect choice for products that use commercial yeast as an ingredient. Propionates effectiveness is measured by the pH of the food, and effective upper limit being considered as 5.5 pH. These substances are used mostly as mold and rope inhibitors in bread, in cheese, non-alcoholic beverages, confections, fillings, frostings, fresh dough, pizza crust, puddings, gelatines, jams, jellies and some meat products. Propionic acid is an oily liquid, soluble in water, with a slight spicy, unpleasant, bad smell. It is also corrosive and flammable, hence needs special care in handling. Propionic acid is produced naturally during the fermentation of some cheeses such as Swiss cheese, in concentrations as high as 1%, thus hindering the growth of molds. Sodium propionate is proposed in baked products that use baking powder and baking soda instead of yeast as the leavening agent, because the existence of calcium ions interrupts the leavening process. Calcium propionate is preferred in baked foods that use yeast, such as breads and rolls, because the nutritional value is increased by the added calcium. Usual level of usage of propionic acid and propionates is 0.1 to 0.4 %.  The parabens are esters of para-hydroxibenzoic acid. The two common esters are methyl and propyl parabens, which are accepted for food use in the United States under the GRAS categorization. The permitted concentration is 0.1 %. They are most active against yeasts and molds. The significant benefits of parabens are their effectiveness at higher pH values, from 3 up to 8, and stability to high and low temperatures. Normally used in bakery products (formulated without yeast), beverages, flavour extracts, food colours, fruit products, jams, jellies, marinated and smoked fish, pickles, salad dressings, syrups, wine and olives (Zakour, 1998). 4. Formulate an argument (pros and cons) regarding the applicability of antibiotics as animal food supplements. There is a risk to give antibiotics to animals along with their feed that can result microbes in the domestic animals to become resistant to the drugs. This can affect people who are eating and handling the meat to become infected with the resistant bacteria contaminated with the pathogens. The majority of the antibiotics used on the farm are not used to treat sick animals but, farmers feed livestock a low-level diet of antibiotics to promote animals to grow faster and, more efficiently. However this practice has more and more become the focus of anxiety. Studies have already established evidence that the use of antibiotics on farms has caused a raise in antibiotic-resistant cases of food poisoning as a result of campylobacter and salmonella bacteria in people. The researchers point to the antibiotic drug called Virginiamycin has been used on livestock ever since 1974. It is found that Virginiamycin-resistant bacteria in as much as 50 percent of supermarket chicken, turkey and pork. Because of consumption these meat the effectiveness Synercid considerably reduced in humans, which causes anxiety and concern of the use of Virginiamycin to promote the growth of food animals. It is not easy to establish the chain of proof needed to say for certain that the Virginiamycin in animals results in resistance to Synercid in humans. Supporters of animal antibiotics state that the scientific evidence connecting Virginiamycin resistance in animals to Synercid resistance in humans remains uncertain, and that animal antibiotics usually cause no instant danger to people. Researches have established Synercid resistance in 1 percent to 4 percent of humans tested, and that is far below the rate of Virginiamycin resistance found in animals. However a detailed study in this regard is needed. In Europe, administrators have already barred the farm use of Virginiamycin and three other growth-promoting antibiotics, in keeping with the suggestions from the World Health Organization. Legislation to enforce a similar ban in the United States was initiated in Congress by Rep. Sherrod Brown (D-Ohio). The FDA is making effort to fully understand and enumerate the risk to humans posed by antibiotic use in animals, and will take up a proper risk appraisal of Synercid and Virginiamycin (Kaufman, 2000). 5. How are NaCl and sugar used in food preservation? Most microorganisms cannot live in a comparatively dry environment. This is how NaCl and sugar accomplish as food preservatives. When a microbe is in non-saline surroundings, existing water can pass through the membrane of the microbe easily. In the non-saline environment, water inside and outside of the cell comes into balance because of diffusion. The diffusion causes water to move from areas of low concentration of solutes to areas of high concentration of solutes. (A solute is any matter that can be dissolved in water). This means that the quantity of water moving out of the cell is the same as water moving into the cell. This process should go on for the organism to stay alive. On the other hand, if salt is added to the water to create a saline environment, this makes an isotonic condition for the cell causing more water moving out of the cell than moving into the cell. This arrests the growth for the microbe or even death. This effect of salt has been used since thousands of years to preserve food. Normally it takes about 20% salts to restrain microbes. Yet, there are some microbes that can survive high salt concentrations. Sugar acts as the same way as salt, but it takes larger quantity of sugar than salt to create the same result (Davis and Conner, 2001). 6. Using examples, describe what indirect antimicrobials are. Garlic and NaCl are among the frequently used natural indirect antimicrobials in food preparations and preservation. These constituents are used in many Philippine meat food schemes as well as cured meat according to a specified formula at typical levels for garlic and NaCl, respectively (Hoogenkamp, 2001). Features of the various types of indigenous sausages produced from different areas of the nation are explained by the concentrations of garlic and NaCl present in these a variety of products. The action of NaCl as an antimicrobial agent is based mostly on its plasmolytic effect on microbial cell membrane (Shelef and Seiter, 1993). Elevated levels of NaCl in culture broths osmotically strain microbial cells resulting to reduced turgor stress of the cell membrane, liberate of microbial cytoplasmic water, and cause cell shrinkage (Jay, 1986). The major antimicrobic component of garlic (Allium sativum) was reported to be allicin. Microbial RNA synthesis and activity of sulfhydryl-containing enzymes (Wills, 1956) are some of the physiological processes identified to be affected by allicin in microorganisms. Fresh garlic extracts included in culture broth have an inhibitory effect on growth of several microorganisms of public health consequence. But, there is incomplete information regarding the efficacy of garlic in combination with other natural antimicrobials to control growth of pathogenic organisms in food systems. Furthermore, there is imperfect information relating to the antimicrobic relations of garlic with other constituents in the food system known to have natural antimicrobial properties. References Davis, M. and Conner, D. (2001) You Are What You Eat [Online] Theme B: Food Science/Technology and Processing Module I.B.2-Food Preservation. Available from:< http://www.eng.auburn.edu/~wfgale/usda_course/section0_5.htm> [26 January 2008]. Hoogenkamp, H.W. (2001). Soy protein and Meat Formulations. Protein Technologies Intl.-A Dupont Business, St. Louis. Howley, J. (2001) Natural & Synthetic Chemical Food & Cosmetic Preservatives Parabens, Sulphites, Benzoates, Nitrates & Nitrites, Propionic Acid and Propionates, and Ascorbic Acid [Online] Available from: [26 January 2008]. Jay, J.M. (1986). Modern Food Microbiology. Van Nostrand-Reinhald, New York. Kaufman, M. (2000). Antibiotics in Animal Feed--A Growing Public Health Hazard Worries Rise over Effect of Antibiotics in Animal Feed [Online] Organic Consumers Association - 6771 South Silver Hill Drive, Finland MN 55603 Available from: [26 January 2008] Shelef, L.A. and Seiter, J.A. (1993) Indirect antimicrobials. In Antimicrobials in Foods, ed. by P.M. Davidson and A.L. Branen. Marcel Dekker, Inc., New York, pp.539-562. Wills, E.D. (1956). Enzyme inhibition by allicin, the active principle of garlic. Biochem., 63, 514 Zakour, O.P.(1998) Chemical Food Preservatives: Propionates and Parabens. [Online] Venture Vol. 1 No. 3 A Quarterly Newsletter Published by NYS Food Venture Center Geneva, NY. Available from: [26 January 2008]. . Read More