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Home , Food system

INGREDIENTS OF THE SYSTEM

BACKGROUND READING 1 "How we eat determines, to a considerable extent, how the world is used."1 –Wendell Berry, author and farmer

Food holds many meanings and serves many roles. At its most basic level, it is a source of nourishment, without which we would cease to function. On a global scale, nations depend on food for political stability.2 Among the one in six people worldwide who lack adequate access to food,3 it may be viewed as a rare and precious . Others who enjoy access to an abundant food supply may take it for granted; in many parts of the world, consumers and food industries discard it in great quantities.4 Beyond its biological roles, food has deep social meaning; it can serve as a mark of culture, values or taste, a gathering point among communities or an opportunity to reinforce relationships.5,6 On a personal level, food and emotion are closely tied.7 Food may provide temporary relief from anxiety, depression, loneliness and boredom.7 Feelings of joy and other positive emotions may inspire healthier, more pleasurable eating experiences.7

These examples illustrate just a few of the ways that food is an integral part of human lives. We all experience food, if for no other reason than because we all consume it. Our relationship with food, however, extends far beyond the act of eating.

Food takes a complex journey from its origins on farm fields, ranches, rivers, oceans and other sources to consumers’ plates. Along the way, it passes through the hands of producers (including farmers, ranchers and fishermen), processors, transporters, warehouse operators, retailers, consumers and waste handlers. The term food system or describes this series of interdependent links, including the people and resources involved at each stage. In this curriculum, we frequently refer to five major stages along the supply chain: production, processing, distribution, retail and consumption. The sequence in which modules are listed roughly follows this chain of events.

The stages along the supply chain do not occur in a vacuum. They depend upon parts of the natural environment, such as soil, freshwater and countless organisms. They are influenced by people and organizations, including businesses, policymakers, nonprofits and ordinary citizens. In turn, the activities taking place along the supply chain affect, both positively and negatively, human , equity and the natural environment. The study of the food system encompasses all of these interrelated parts. Looking at the connections between food, health, society and the environment in this way, one can imagine how what we eat determines “how the world is used.”1

TEACHING THE FOOD SYSTEM | A PROJECT OF THE JOHNS HOPKINS CENTER FOR A LIVABLE FUTURE 1 INGREDIENTS OF THE FOOD SYSTEM | BACKGROUND READING Why study the food system? Through understanding—and working with—the food system, health advocates, researchers, policymakers, business owners and otherwise engaged citizens can foster positive changes. These include promoting healthier diets, reducing the risk of foodborne illness and other diseases, upholding workers’ rights, supporting small businesses, conserving natural resources, mitigating climate change, improving air and water quality, and protecting .

Food and health The food system is essential to health for the obvious reason that we depend on a safe and adequate food supply to survive. Globally, —the production of food and goods through growing crops and raising animals—provides the vast majority of the raw and ingredients that form the basis of our food supply.8 Food processing—the practices used to transform raw plant and animal materials into products for consumers9-11—can extend the availability of certain foods and reduce the risk of foodborne illness.10,12-15 To deliver food to hungry consumers, it must be transported. Densely populated cities, in particular, may not be able to feed themselves without relying on food produced on remote farmland.16 Finally, food outlets, such as supermarkets, schools and farmers’ markets, may provide consumers with access to a wide variety of food choices.

Each stage of the food system, from field to plate, can produce activities that are detrimental to health. The use of chemical pesticides, a practice common in the industrial model of agriculture in the United States, poses health risks to farm workers and consumers.17-19 The prevailing approach to raising animals for , eggs and dairy is called industrial food animal production (IFAP).20 Potential health harms associated with IFAP include the spread of disease from animals to humans, a risk that is increased by housing many animals in crowded facilities (sometimes called concentrated animal feeding operations, or CAFOs).20 Animal waste, known to harbor pathogens (disease-causing organisms) and harmful chemicals, may contaminate air, water, soil and the food supply,20 through which people may be exposed. Gases and other airborne materials arising from stored animal waste can cause respiratory and neurological illnesses in IFAP workers and nearby communities.20 The routine use of , primarily to promote animals’ growth,20 can foster the generation of -resistant pathogens, which can cause human infections that are difficult or impossible to treat.20-27 Slaughtering animals and meat processing can present additional risks to workers’ health and the safety of the food supply. Injuries in the food processing industry as a whole are among the highest in any job category.28 The scale of the current food processing industry contributes to foodborne illness outbreaks; as processing plants become larger, they handle greater volumes of products—sometimes from many different sources—and distribute them over a broader geographic area.28 This practice increases the risk of widespread exposure to contaminated products.28 The conditions under which food is transported, stored and prepared can also contribute to foodborne illness.29,30 These are just a few examples; for more information, refer to Unit II: From Field to Plate.

TEACHING THE FOOD SYSTEM | A PROJECT OF THE JOHNS HOPKINS CENTER FOR A LIVABLE FUTURE 2 INGREDIENTS OF THE FOOD SYSTEM | BACKGROUND READING Food and diet are major determinants of health. Rates of obesity31 and diabetes32 have risen to epidemic proportions in the United States. Heart disease, obesity, diabetes and other related conditions are among the leading causes of death.33-35 In general, Americans eat too many nutrient- poor foods made with refined , added fats and added sugars; and too few nutrient-dense foods like and .36,37 These dietary patterns are not solely determined by individual will. External factors may play a considerable role; these include the influence of family and peers, food advertising, the cost of food and physical access to food stores —all part of what has been called the food environment (see Unit III: Eating, and Food Environments).38

Many of the health harms and benefits of the food system are the indirect result of its effect on the environment. Climate change, for example, is generally viewed as a major threat to public health, equity, , freshwater supplies and .39-43 Impacts to the environment that diminish the long-term viability of the food supply have downstream effects on nutrition. The relationship between food and the environment is discussed below.

Food and justice The harms and benefits of the food system are not equally shared.31,44 Certain segments of the population, particularly low-income, minority and immigrant communities, bear a heavier burden of health risks associated with food production and processing.18,45-51 Some communities may have less access to healthy food stores in their neighborhoods, potentially putting the residents at greater risk for diet-related diseases.52,53 The price of some foods may also be a barrier to adopting healthier diets among lower-income families.54-56 These and other inequalities illustrate the significance of equity, or fairness, in the food system—sometimes called food justice.57

Food and the environment Environmental effects on the food system The term environment refers to the living (biological) and nonliving (physical) components of our surroundings. We frequently use it to refer to natural and human environments, such as farms, rivers, oceans, forests and the organisms that inhabit these places. The term is also sometimes used to refer to the organisms living in a place, their physical environment and all of the interactions within.58

Living organisms play essential roles in providing our food supply. The most apparent examples are the domesticated animals and crop plants that we directly depend on for food. Less obvious are the countless wild organisms that play supporting roles in farming, ranching and other forms of food production. Certain birds, insects, fungi and bacteria, for example, perform essential functions such as pollination, controlling pests or providing crops with the necessary nutrients for growth. Greater biodiversity—the genetic diversity among these domesticated and wild organisms—

TEACHING THE FOOD SYSTEM | A PROJECT OF THE JOHNS HOPKINS CENTER FOR A LIVABLE FUTURE 3 INGREDIENTS OF THE FOOD SYSTEM | BACKGROUND READING promotes a more abundant and stable food supply.17,59,60 For more information, refer to Agriculture and Ecosystems.

Not all organisms are beneficial from a human perspective. The term pest refers to any organism that threatens human interests.61 The definition for what is considered a pest is, of course, subjective.61 In agriculture, common pests include certain plants (weeds), insects, fungi, bacteria and other organisms that can kill crops or interfere with their growth. Ironically, the technological solutions designed to control agricultural pests, including certain insecticides and herbicides, sometimes cause health and environmental harms.17,62 Certain bacteria, viruses and other pathogens can also infect animals or contaminate food, potentially posing dangers to human health. The science of protecting the food supply from viral, bacterial and other forms of contamination is called . For more information, refer to Food Safety.

Nonliving parts of the environment include air, water and climate, all critical to food production. Most of our food supply, for example, depends on soil and the organisms living within it.8 Climate— the overall weather conditions over a long period of time—is a major factor in determining the type and quantity of foods that can be produced in a region. For more information, refer to Agriculture and Ecosystems.

Not every part of the environment is “natural.” Human-made surroundings, sometimes called the built environment, include homes, schools, stores, neighborhoods, cities, and the roads and railways that connect them. The built environment has a strong effect on what people eat. For example, the type and distribution of food stores in a community are often associated with the diets of residents and their health.63 People who live in areas with limited access to healthy food tend to have poorer diets, and they suffer more from obesity and diabetes.64-66 Buses and other means of transportation can play an important role in improving access to healthy food outlets.67-69 For more information, refer to Food Environments.

Food system effects on the environment Living and nonliving parts of the environment are affected, both positively and negatively, by the activities along the food chain.

Well-managed agriculture, for example, can provide habitats for wildlife,70 sequester that contribute to climate change71 and foster healthy ecosystems.

Practices in the food system can also have detrimental effects on the natural environment. Food production, for example, can degrade finite natural resources8,72-74 and negatively impact biodiversity, climate, water quality and animal welfare.17,75-77 Various forms of waste are generated during food production, processing, distribution, retail and preparation.4,78,79 All of these stages require energy use,80,81 particularly at the household level.82 Depending on the source, energy use can contribute to climate change, depletion, poor air quality and other harms.81 Many of these environmental harms also negatively impact human health. TEACHING THE FOOD SYSTEM | A PROJECT OF THE JOHNS HOPKINS CENTER FOR A LIVABLE FUTURE 4 INGREDIENTS OF THE FOOD SYSTEM | BACKGROUND READING For more information on the effect of the food system on the environment, refer to the modules in Unit II: From Field to Plate.

Impacts to animal welfare are discussed in Food Animal Production.

Dominant and alternative systems Many of the health, environmental and social harms described here result from practices associated with the dominant U.S. food system. We refer to this as the industrial food system (see History of Food). Industrialization is not, however, inherently harmful and has in some respects greatly increased efficiency within the food system.83,84

Alternative parts of the supply chain, such as , pasture-based systems and other forms of agriculture that strive to be more sustainable, may reduce or minimize some of the harms associated with the industrial system. These practices may promote public health, uphold social justice, reduce pollution, conserve biodiversity, minimize the depletion of finite resources or protect animal welfare.17 Alternative forms of processing, distribution, marketing and retail can be seen as part of the small but growing efforts to build local and regional food systems (refer to and ).85 These may support smaller farmers,85 strengthen local economies85 and allow consumers to connect with the origins of their food.86,87 In some cases, local and regional food distribution may reduce the energy use and climate impacts associated with transport, though smaller shipments may result in efficiency losses.88,89 Alternatives in the food system are discussed in greater detail throughout units II and III.

Systems thinking The food system and its relationship with health, society and the environment form a larger, interconnected whole. An understanding of how these connected parts are related, and how changing one part might affect the others, is essential to any attempt to foster change in the food system.

When the complexity of systems is not taken into account, unpredicted and undesired outcomes often result. The heavy reliance on agricultural chemicals is an example of a practice that may provide short-term benefits (fewer pests and greater crop growth, for example) alongside more indirect harms to health and ecosystems, such as elevated cancer risks17 and polluted waterways.76,77

Harms arising from the food system might be prevented or reduced by better accounting for the numerous and complex connections between food, health, society and the environment. An effective approach would likely involve partnerships between many different stakeholders in the system, including farmers, policy makers, scientists, industries and citizen groups. This systems approach can help us better understand, and change, “how the world is used.”1

TEACHING THE FOOD SYSTEM | A PROJECT OF THE JOHNS HOPKINS CENTER FOR A LIVABLE FUTURE 5 INGREDIENTS OF THE FOOD SYSTEM | BACKGROUND READING References 1. Berry W. The pleasures of eating. In: What are People For? New York: North Point Press; 1990. 2. Godfray HCJ, Beddington JR, Crute IR, et al. Food security: the challenge of feeding 9 billion people. Science. 2010;327(5967):812-8. 3. Food and Agriculture Organization of the United Nations. Hunger. 2011. Available at: http://www.fao.org/hunger/en/ [Accessed June 2011]. 4. Parfitt J, Barthel M, Macnaughton S. Food waste within food supply chains: quantification and potential for change to 2050. Philosophical Transactions of the Royal Society B: Biological Sciences. 2010;365(1554):3065- 3081. 5. Counihan C, Esterik PV. Food and Culture: A Reader. New York, NY: Routledge; 1997:424. 6. Quandt S, Arcury TA, Bell RA, McDonald J, Vitolins MZ. The social and nutritional meaning of food sharing among older rural adults. Journal of Aging Studies. 2001;15(2):145-162. 7. Canetti L, Bachar E, Berry EM. Food and emotion. Behavioural processes. 2002;60(2):157-164. 8. Pimentel D. Soil erosion: a food and environmental threat. Environment, Development and Sustainability. 2006;8(1):119-137. 9. Heldman DR, Hartel RW. Principles of Food Processing. New York: Chapman and Hall; 1997. 10. Truswell AS, Brand JC. Processing food. British Medical Journal. 1985;291(6503):1186-90. 11. Monteiro CA, Levy RB. A new classification of foods based on the extent and purpose of their processing. Public Health Nutrition. 2010;26(11):2039-2049. 12. Smith JS, Hui YH. Food Processing: Principles and Applications. Ames, Iowa: Wiley-Blackwell; 2004. 13. Wiley RC. Minimally Processed Refrigerated Fruits & Vegetables. New York: Chapman & Hall; 1994. 14. Ohlsson T, Bengtsson N. Minimal Processing Technologies in the . Boca Raton, FL: CRC Press; 2002. 15. Alzamora SM, Tapia MS, López-Malo A. Minimally Processed Fruits and Vegetables: Fundamental Aspects and Applications. Gaithersburg, MD: Aspen Publishers, Inc. 2000. 16. Peters CJ, Bills NL, Lembo AJ, Wilkins JL, Fick GW. Mapping potential foodsheds in New York State: a spatial model for evaluating the capacity to localize food production. Renewable Agriculture and Food Systems. 2008;24(1):72-84. 17. Horrigan L, Walker P, Lawrence RS. How can address the environmental and public health harms of . Environmental Health Perspectives. 2002;110(5). 18. Frank A, McKnight R, Kirkhorn S, Gunderson P. Issues of agricultural safety and health. Annual Review of Public Health. 2004;25:225-245. 19. Calvert GM, Karnik ÃJ, Mehler L, et al. Acute pesticide poisoning among agricultural workers in the United States, 1998-2005. American Journal of Industrial Medicine. 2008;51:883-898. 20. Pew Commission on Industrial Farm Animal Production. Putting Meat on the Table: Industrial Farm Animal Production in America. 2008. 21. Teuber M. Veterinary use and antibiotic resistance. Current Opinion for Microbiology. 2001;4:493-499. 22. Smith D, Harris A, Johnson J, Silbergeld E, Morris J. Animal antibiotic use has an early but important impact on the emergence of antibiotic resistance in human commensal bacteria. Proceedings of the National Academy of Sciences of the United States of America. 2002;99:6434-6439. 23. Gupta A, Nelson JM, Barrett TJ, et al. Antimicrobial resistance among Campylobacter strains, United States, 1997-2001. Emerging Infectious Diseases. 2004;10(6):1102-1109. 24. File TMJ. Clinical implications and treatment of multi-resistant Streptococcus pneumoniae pneumonia. Clinical Microbial Infections. 2006;12:31-41.

TEACHING THE FOOD SYSTEM | A PROJECT OF THE JOHNS HOPKINS CENTER FOR A LIVABLE FUTURE 6 INGREDIENTS OF THE FOOD SYSTEM | BACKGROUND READING 25. Spellberg B, Guidos R, Gilbert D, et al. The epidemic of antibiotic-resistant infections: a call to action for the medical community from the Infectious Diseases Society of America. Clinical Infectious Diseases. 2008;46(2):155-164. 26. Iovine M, Blaser M. Antibiotics in animal feed and spread of resistant Campylobacter from to humans. Emerging Infectious Diseases. 2004;10(6):1158-1159. 27. Silbergeld EK, Graham J, Price LB. Industrial food animal production, antimicrobial resistance, and human health. Annual Review of Public Health. 2008;29:151-169. 28. Woteki CE, Kineman BD. Challenges and approaches to reducing foodborne illness. Annual Review of Nutrition. 2003;23:315-44. 29. Kessel J Van, Karns J, Gorski L, McCluskey B, Perdue M. Prevalence of salmonellae, listeria monocytogenes, and fecal coliforms in bulk tank milk on US dairies. Journal of Dairy Science. 2004;87(9):2822-2830. 30. USDA Food Safety and Inspection Service. Be food safe: four easy lessons in safe food handling. 2007. Available at: http://www.fsis.usda.gov/PDF/BFS_Brochure.pdf. 31. Wang Y, Beydoun MA. The obesity epidemic in the United States - gender, age, socioeconomic, racial/ethnic, and geographic characteristics: a systematic review and meta-regression analysis. Epidemiologic Reviews. 2007;29:6-28. 32. CDC Division of Diabetes Translation. Long-term Trends in Diabetes. 2010. 33. Mokdad AH, Marks JS, Stroup DF, Gerberding JL. Actual causes of death in the United States, 2000. JAMA. 2004;291(10):1238-45. 34. Flegal KM. Excess deaths associated with underweight, overweight, and obesity. JAMA. 2005;294(5):552- 553. 35. Hajjar I, Kotchen JM, Kotchen TA. Hypertension: trends in prevalence, incidence, and control. Annual Review of Public Health. 2006;27:465-90. 36. Grotto D, Zied E. The Standard American Diet and its relationship to the health status of Americans. Nutrition in Clinical Practice. 2010;25(6):603-12. 37. Farah Wells H, Buzby JC. Dietary Assessment of Major Trends in U.S. Food Consumption, 1970-2005. 2008. 38. Story M, Kaphingst KM, Robinson-O´Brien R, Glanz K. Creating healthy food and eating environments: policy and environmental approaches. Annual Review of Public Health. 2008;29:253-272. 39. Schmidhuber J, Tubiello FN. Global food security under climate change. Proceedings of the National Academy of Sciences. 2007;104(50). 40. Nelson GC, Rosegrant MW, Koo J, Robertson R. Climate Change: Impact on Agriculture and Costs of Adaptation. Washington, D.C.: International Research Institute; 2009. 41. Intergovernmental Panel on Climate Change. Climate Change 2007: Synthesis Report. Valencia, Spain; 2007. 42. Patz JA, Gibbs HK, Foley JA, Rogers JV, Smith KR. Climate change and global health: quantifying a growing ethical crisis. EcoHealth. 2007;4(4):397-405. 43. Patz J. Public health risk assessment linked to climatic and ecological change. Human and Ecological Risk Assessment. 2001;7(5):1317-1327. 44. Neff R, Palmer A, McKenzie S, Lawrence R. Food systems and public health disparities. Journal of Hunger & Environmental Nutrition. 2009;4(3):282-314. 45. Gouveia L, Juska A. Taming nature, taming workers: constructing the separation between meat consumption and meat production in the US. Sociologia Ruralis. 2002;42(4). 46. Lipscomb H, Argue R, McDonald M, et al. Exploration of work and health disparities among black women employed in poultry processing in the rural South. Environmental Health Perspectives. 2005;113:1833-1840. 47. Cooper M. The Heartland`s raw deal: how meatpacking is creating a new immigrant underclass. Rowman and Littlefield; 2007. 48. McCauley L, Lasarev M, Higgins G, et al. Work characteristics and pesticide exposures among migrant agricultural families: a community-based research approach. Environmental Health Perspectives. 2001;109:533-538. TEACHING THE FOOD SYSTEM | A PROJECT OF THE JOHNS HOPKINS CENTER FOR A LIVABLE FUTURE 7 INGREDIENTS OF THE FOOD SYSTEM | BACKGROUND READING 49. Lipscomb H, Loomis D, McDonald M, Argue R, Wing S. A conceptual model of work and health disparities in the United States. International Journal of Health Services. 2006;36:25-50. 50. Donham K, Wing S, Osterberg D. Community health and socioeconomic issues surrounding concentrated animal feeding operations. Environmental Health Perspectives. 2007;115:317-320. 51. Mirabelli MC, Wing S, Marshall SW, Wilcosky TC. Race, poverty, and potential exposure of middle-school students to air emissions from confined swine feeding operations. Environmental Health Perspectives. 2006;114:591-596. 52. Morland K, Wing S, Diez Roux A. The contextual effect of the environment on residents` diets: the atherosclerosis risk in communities study. American Journal of Public Health. 2002;92(11):1761-1767. 53. Morland KB, Evenson KR. Obesity prevalence and the local food environment. Health & Place. 2009;15(2):491-495. 54. Powell LM, Chaloupka FJ. Food prices and obesity: evidence and policy implications for taxes and subsidies. Milbank Quarterly. 2009;87(1):229-257. 55. Dong D, Lin BH. and Consumption by Low-Income Americans: Would a Price Reduction Make a Difference? 2009. 56. Golan E, Stewart H, Kuchler F, Dong D. Can low-income Americans afford a healthy diet? Amber Waves. 2008;6(5). 57. Gottlieb R, Joshi A. Food Justice. Cambridge, MA: MIT Press; 2010. 58. Encyclopedia Brittanica. Ecosystem. Britannica Online Encyclopedia. 2011. Available at: http://www.britannica.com/EBchecked/topic/178597/ecosystem [Accessed May 31, 2011]. 59. Fowler C, Mooney P. Shattering: Food, Politics, and the Loss of Genetic Diversity. Tuscon, AZ: The University of Arizona Press; 1990:278. 60. Food and Agriculture Organization of the United Nations. Agroecosystem Biodiversity. 2010;(August 2). Available at: http://www.fao.org/biodiversity/ecosystems/bio-agroecosystems/en/. 61. Encyclopedia Brittanica. Pest (vermin). Britannica Online Encyclopedia. 2011. Available at: http://www.britannica.com/EBchecked/topic/453421/pest [Accessed May 31, 2011]. 62. Lewis W, Lenteren J van, Phatak S, Tumlinson J. A total system approach to sustainable pest management. Proceedings of the National Academy of Sciences of the United States of America. 1997;94(23):12243-12248. 63. Glanz K, Sallis JF, Saelens BE, Frank LD. Healthy nutrition environments: concepts and measures. Am J Health Promot. 2005;19(5):330-333. 64. Moore LV, Diez Roux AV, Nettleton JA, Jacobs DR. Associations of the local food environment with diet quality—a comparison of assessments based on surveys and geographic information systems. American Journal of Epidemiology. 2008;167(8):917-924. 65. Goldstein H, Harvey S, Banthia R, et al. Designed for Disease: The Link Between Local Food Environments and Obesity and Diabetes. Center for Public Health Advocacy, PolicyLink, and the UCLA Center for Health Policy Research; 2008. 66. Franco M, Diez Roux AV, Glass TA, Caballero B, Brancati FL. Neighborhood characteristics and availability of healthy foods in Baltimore. American Journal of Preventive Medicine. 2008;35(6):561-567. 67. Antin T, Hora M. Distance & Beyond: Variables influencing conceptions of food store accessibility in Baltimore, MD. Practicing Anthropology. 2005;27(2):15-17. 68. Kaufman P. Rural poor have less access to supermarkets, large grocery stores. Rural Development Perspectives. 1999;13(3):19-26. 69. Weinberg Z. No place to shop: Food access lacking in the inner city. Race, Poverty, and the Environment. 2000. 70. American Farmland Trust. Farmland Protection. 2009. Available at: http://farmland.org/programs/protection/default.asp [Accessed May 27, 2011]. 71. Lal R. Soil carbon sequestration impacts on global climate change and food security. Science. 2004;304(5677):1623-7.

TEACHING THE FOOD SYSTEM | A PROJECT OF THE JOHNS HOPKINS CENTER FOR A LIVABLE FUTURE 8 INGREDIENTS OF THE FOOD SYSTEM | BACKGROUND READING 72. Frumkin H, Hess J, Vindigni S. Peak petroleum and public health. JAMA. 2007;298(14). 73. Cordell D, Drangert J-O, White S. The story of phosphorus: global food security and food for thought. Global Environmental Change. 2009;19(2):292-305. 74. Strzepek K, Boehlert B. Competition for water for the food system. Philosophical Transactions of the Royal Society of London. 2010;365(1554):2927-2940. 75. Weber CL, Matthews HS. Food-miles and the relative climate impacts of food choices in the United States. Environmental Science and Technology. 2008;42(10):3508-13. 76. Howarth R. Coastal nitrogen pollution: a review of sources and trends globally and regionally. Harmful Algae. 2008;8(1):14-20. 77. Diaz RJ, Rosenberg R. Spreading dead zones and consequences for marine ecosystems. Science. 2008;321(5891):926-9. 78. Senauer B, Asp E, Kinsey J. Food Trends and the Changing Consumer. St. Paul, Minnesota: Eagan Press; 1991. 79. Marsh K, Bugusu B. - roles, materials, and environmental issues. Journal of Food Science. 2007;72(3):R39-55. 80. Steinhart JS, Steinhart CE. Energy use in the U.S. food system. Science. 1974;184:307-316. 81. Woods J, Williams A, Hughes JK, Black M, Murphy R. Energy and the food system. Philosophical Transactions of the Royal Society of London. 2010;365(1554):2991-3006. 82. Canning P, Charles A, Huang S, Polenske KR, Waters A. Energy Use in the U.S. Food System. Economic Research Service, USDA; 2010. 83. USDA Economic Research Service. Agricultural Productivity in the United States. 2010. Available at: http://www.ers.usda.gov/Data/AgProductivity/ [Accessed June 1, 2011]. 84. Ikerd JE. Sustaining the profitability of agriculture. In: Economist’s Role in the Agricultural Sustainability Paradigm. San Antonio, TX: University of Missouri; 1996. 85. Martinez S, Hand M, Pra M Da, et al. Local Food Systems: Concepts, Impacts, and Issues. USDA Economic Research Service; 2010. 86. Food Marketing Institute. U.S. Grocery Shopper Trends. Arlington, VA; 2009. 87. King RP, Hand MS, DiGiacomo G, et al. Comparing the Structure, Size, and Performance of Local and Mainstream Food Supply Chains. ERS; 2010. 88. Hill H. : Background and Marketing. Fayetteville, AR; 2008. 89. Pirog R, Pelt T Van, Enshayan K, Cook E. Food, Fuel, and Freeways: An Iowa Perspective on How Far Food Travels, Fuel Usage, and Greenhouse Gas Emissions. Ames, Iowa: Leopold Center for Sustainable Agriculture; 2001.

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