Note: This webpage is for instructional purposes only and the scenario described below is fictional.

Food Processing, Nutrition, and Environment

UW-Madison Task Force Members:
   Justin Hill, Department of Biology
   Ayla Masrin, Department of Nutritional Sciences

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Scenario | Abstract | Introduction | Methods | Results | Limitations | Conclusions | Citations | Acknowledgements | About the Authors

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Scenario

      We've been approached by the USDA to combine current literature on nutrition and sustainability in order to assess the effectiveness of food processing. We aim specifically to look at the environmental, social, economic, and nutritional implications of food processing to address two issues: 1) Is processing a realistic solution to the global health issue of food insecurity as it relates to obesity and micronutrient deficiency? 2) Does processing put future generation's environmental, social, or economic stability at risk?

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Abstract

The original intent of food processing is to extend shelf-life and preserve the food product; however, the increasing trend of obesity in the modern world correlates to an increase in ultra-processed food (UPF) consumption that includes energy dense snacks and drinks. Meanwhile, some processed foods are not linked with this obesity trend, such as processed vegetables and pre-prepared meats. These supply an easy, affordable alternative to fresh foods. This study aims to combine current research to analyze the food processing industry in terms of nutrition and the three pillars of sustainability: environment, society, and economy. Social and economic sustainability center around the consumer’s perspective. Food processing, agriculture, and storage contribute largely to the environment in greenhouse gas (GHG) emissions and waste. Three food processes were studied for the nutrition and environmental impacts: ultra-processed foods (UPFs), processed vegetables, and processed “convenient” meats. UPFs contained the least nutritional content, while processed vegetables were high in nutrition, and both were relatively environmentally sustainable. Processed meats had the greatest environmental impact, but the nutritional content was not altered from the starting product thanks to technological advancements. These foods were all  popular among consumers because of their ease of preparation and storage. Increasing efficiency of technologies throughout the food production system would benefit both the environmental and economic sustainability of the system. Meanwhile, more affordable, easy, healthy food choices would increase the social sustainability of the food production system and combat the increasing trend of unhealthy diets, so this is where future research should be focused. 

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Introduction

Food processing techniques have increased accessibility and convenience of various food products. However, like any new technology, it has some tradeoffs. The increased efficiency in the food production system was necessary to provide enough food for the growing population on Earth. With this increased efficiency, four main issues must be taken into account. The first concern is with potential health risks associated with increased processing, while the remaining three are concerns with sustainability of the food production system.

Micronutrients are imperative for health in metabolism, blood, and tissue function (Shenkin, 2006). While there is a growing trend of energy dense foods, these foods rarely contain the necessary micronutrients for good health (Louzada et al., 2015b). We examined the nutritional content of vegetables due to the high content of vital vitamins and minerals in these foods. Meanwhile, meats were included in the study because of the high protein value, containing essential amino acids for our body’s function. Protein contributes to a variety of physiological functions, including bone health (Bonjour, 2005) and muscle protein synthesis. Dietary amino acids provide the backbone for muscle synthesis, and can ultimately benefit an individual’s bodily functions, especially in aging populations (Paddon-Jones and Rasmussen, 2009).

For this study, we define sustainability in terms of the three pillars: environmental, economic, and social. As the UN points out, “Economic development, social development and environmental protection are interdependent and mutually reinforcing components of sustainable development”, (Kuhlman and Farrington, 2010); so altering one aspect of sustainability impacts the other two, proving that research must include all three pillars. Since no resource is 100% renewable, we simply consider environmental sustainability to be lowering greenhouse gas (GHG) emissions and food waste to retain resources for future generations. While environmental impacts include numerous other areas, GHG emissions and food waste have been widely studied in the food industry and were therefore the chosen metric in this study. In terms of social sustainability, consumer acceptance and likelihood to purchase the product, without increasing any health risks, is the metric we utilized. More economically sustainable products are those that are cheaper, processed or fresh, as this makes it an option for people of all socio-economic classes.

The increasing trend of processed food consumption has been linked to the increasing trend of obesity (Louzada et al., 2015a), suggesting that the nutritional content of processed foods needs to be enhanced further. The challenge in this issue is integrating everything into a long term solution in terms of food processing, as we predict that more processing in food systems leads to decreased nutritional content and decreased environmental sustainability, while economic and social sustainability increase.

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Methods

We conducted a literature review of current publications on the food production industry in relation to nutrition and the three pillars of sustainability: environmental, economic, and social aspects. We limited our study to packaged food items that would commonly be found in grocery stores, excluding any restaurant products. This study focuses on food processing and agriculture in developed countries.

Nutrition

To examine the impact of food processing on the nutritional content of food products, literature on the nutrition of three processed food groups were included: ultra-processed foods (UPFs), processed vegetables, and processed meats. Ultra-processed foods (UPFs) are defined as industrial food products containing additives not included in culinary preparations of the same base food product (Steele et al., 2016). A wide variety of UPFs were examined, from salty snacks to sweetened beverages. UPFs often contain high fat and reduced sugar contents, and are subsequently associated with the increasing trend of obesity in the developed world. Processed vegetables were restricted to frozen or canned products, with fresh vegetable products included as a comparison. In analyzing the nutritional content of processed versus fresh vegetables, vitamin C, proteins, and other antioxidants were the main focus. The processed meats included lunch meats and other “convenient” meats that were cured, processed, and packaged in bulk such as the meat in pre-made, frozen dinners.

Environment

The metrics for environmental impact included greenhouse gas (GHG) emissions for the three processed food groups, and waste generation from food and packaging. In reviewing GHG emissions in food production, the publications include the agriculture, processing and packaging, and in-store components (refrigeration, freezing, etc.) of the food products. The food and packaging waste was not categorized by types of food in the literature analyzed.

Social

We searched for literature on studies and surveys for consumer preferences in foods based on price, convenience, taste, and other factors. We conducted 15 interviews among peers to gain perspective on what factors drive food choices uniquely for the young adult population on a college campus. The following questions were included in our survey:

1. What is the biggest factor you take into consideration when grocery shopping?
2. Do you consider the environmental effects of the food production when deciding what to purchase?
3. Are you more likely to purchase prepackaged foods or fresh foods?
4. What do you normally snack on?
5. How often do you cook?

Economics

This study focuses mainly on the consumer aspect of economic sustainability. When examining the economic sustainability of processed foods, we did not split it into the three different food groups (UPF, meat, vegetable) because they all had the same general trend of cost going down as nutritional contents decreased (Hawk, 2017).

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Table 1.The mean energy content of various food groups

in the diet of 3700 adults from First Nations communities

in Canada. Source: Batal et al. 2017

Results

Nutrition

The issue with ultra-processed food (UPF) consumption is the increased energy in carbohydrates, sugar, and saturated fats, but decreased protein content, vitamin A, potassium, and other micronutrients. In various Canadian provinces it was found that 59.3% of a person’s energy intake is made up of ultra-processed foods, while only 36.4% of energy intake is acquired by consuming fresh or minimally processed foods (Table 1)(Batal et al., 2017). Meanwhile, in Brazil, 21.5% of a person’s diet is made up of ultra-processed foods (Louzada et al., 2015a), highlighting that low-income households consume more energy dense, nutrient poor food, and are at increased risk for health complications because of it (Drewnowski, 2010). The average person from age 40-59 has a BMI that is .69 higher for a diet consisting of at least 39% UPFs than someone whose diet consists of less than 11% UPF (Louzada et al., 2015a). If the consumption of UPF’s continues to rise due to the fast-paced, convenience driven society we live in, the average BMI will do the same (Botonaki and Mattas, 2010).

Vegetables are a main source of dietary micronutrients, including various vitamins and minerals. While the initial processing may cause a slight decrease in these nutrients, the shelf life can be longer for these processed vegetables. Frozen peas, broccoli, and, spinach had 80% or less of the vitamin C content than their fresh alternatives; however, they maintained consistent vitamin C levels over 21 days while the fresh vegetables stored in both ambient and chilled temperatures dropped below 50% of the initial vitamin C content (Favell et al., 1998). When analyzing water-soluble antioxidant activity, the total activity decreased by more than half in canned and jarred peas. Similarly, canned spinach had less than 30% of the antioxidant activity found in fresh spinach (Hunter and Fletcher, 2002).

With the increased processing and consumption of meats, there is a rising concern in the health implications of “convenient” meats because of the new technologies being used. High pressure processing, a widely used new technology, is cheaper and more environmentally friendly than the high heat processing that was traditionally used (Hugas et al., 2002); however, the effects of this processing method on microorganism growth are still being studied. It has shown that it can yield “shelf-lives similar to thermal pasteurization, while maintaining the natural food quality parameters (nutrients and sensorial preservation)” (Pereira and Vicente, 2010), making the products appealing to consumers. Adult lunchmeat consumers had significantly higher intakes of nutrients such as calcium, potassium, thiamin, and sodium. Additionally, consumers had increased calories, energy adjusted intakes of protein, and saturated fatty acids (Agarwal et al., 2015).

Table 2. Micronutrient fraction content in food products grouped by level of processing. Source: Louzada et al. 2015b		Figure 1. Comparison of vitamin C content in frozen versus fresh peas and green beans over time. Source: Favell et al. 1998		Figure 2.Comparison of vitamin C content in frozen versus fresh spinach over time. Source: Favell et al. 1998

Environment

Figure 3. Mean GHG emissions food groups by GHG emissions origin.

Values are expressed per 100 g (A) and 100kcal (B). Source: Drewnowski et al. 2014

  Greenhouse Gas Emissions

 Globally, food systems contribute 19-29% of the total GHG emissions, a not insignificant amount (Vermeulen et al., 2012). Agriculture contributed about 58% of the GHG emissions with all of the food groups together when looking at the mean GHG per 100 grams of edible product. Processing, packaging, and storage components varied greatly depending on the type of analysis done (per 100 g vs 100 kcal), but regardless, these components still contributed much less GHG emissions than agriculture (Drewnowski et al., 2014).

Agriculturally, the GHG emission contribution by ultra-processed foods varies greatly. Since UPF’s start as regular, unprocessed foods and are then processed into UPF’s, the effect they have on the environment depends on the kind of UPF considered.Once the foods are taken for processing, all of the UPFs have about the same amount of GHG emissions, which is only about 1% of the total emissions created in the food production system. Finally, the GHGs from the storage in stores is also highly variable due to the wide array of foods in the UPF category (Drewnowski et al., 2014).

The environmental impact of vegetable processing lies largely in the agriculture and in store components. In a study of Australian agriculture the environmental impact of 23 vegetable crops were compared, finding an average of 9.2 tons of carbon dioxide emissions per hectare of cropland. The major sources of emissions in vegetable agriculture came from the electricity in irrigation (54%) and post-harvest activity (11%), as well as nitrogen fertilizers in the soil (17%). Targeting alternative sources for energy for electricity, such as solar energy, could effectively decrease these emissions. Additionally, keeping water-filled spaces in the soil at less than 40% or decreasing soil compaction, and thereby increasing oxygen diffusion in the soil would reduce emissions from nitrogen fertilizers (Maraseni et al., 2010). When the energy density of the food product was factored in, the GHG emissions per 100 kcal were significantly higher in vegetable processing than in other food categories, suggesting that replacing meats with vegetables in equal caloric content would result in an increase in overall GHG emissions. The main source of the emissions when analyzed per 100 kcal were the in store components of electricity, refrigeration, and freezing of processed products, which came out to about 8% of the total GHG emissions and 36% of the emissions from the vegetable food group as a whole(Drewnowski et al., 2014).

Meat products have the highest GHG emissions per 100 grams of product out of any of the food groups, processed or not. The meat agriculture GHG emissions produced are 41% of the total agricultural emissions (Drewnowski et al., 2014). Once the meat is into the processing stage, though, the GHG emissions are being greatly reduced thanks to new technology. High hydrostatic pressure techniques reduce GHG emissions because of the small amount of energy needed to compress a solid or liquid to 500 MPa as compared to heating to 100 °C (Pereira and Vicente, 2010). The meat storage GHG per 100 grams is about 2.5% of the total emissions, and about 13% of the emissions created by meats (Drewnowski et al., 2014).

          Waste Generation

Food production and processing requires resources, such as water, nutrients, energy, and land. The increasing trend of food waste in the US increases the amount of resources being utilized for food production and thereby increases GHG emissions. Additionally, GHG emissions increase due to rotting food waste in landfills producing methane (Hall et al., 2009). Municipal solid waste (MSW), which includes both the packaging and food waste, from waste landfills in the US contributed to approximately 18.1% of total US methane emissions in 2013 (Lee et al., 2016). Consequently, reducing total waste from food production in the form of food and packaging materials would reduce the total methane emissions in the US, and allow reduced food production.

Since food processing extends shelf life ( Marsh and Bugusu, 2007), consumers are less likely to throw these products away due to spoilage. In his study comparing food and drink waste in the UK, Parfitt et al. (2010) classified waste as either avoidable, possibly avoidable, or unavoidable (Figure 4). The study broke down waste into various stages of food production, including harvesting, processing, packaging, and post-consumer waste. Total food and drink waste amounted to 14 megatonnes (Mt) in the UK, with the majority arising from household waste. Household food and drink waste consisted of almost 60% of the total value, with 37.9% of the total consisting of avoidable waste and an additional 10.7% being possibly avoidable. This amounts to almost 48.6% of the total food and drink waste in the UK being avoidable. This study also breaks down the waste by food groups, including processed foods and fresh foods (Figure 5). The largest contributors to food waste included fresh vegetables and fruits, whereas the processed alternatives made up a significantly smaller amount in comparison. In processing foods, the products are made to last longer, thus contributing to less waste than fresh alternatives. An increased trend among communities of purchasing processed instead of fresh vegetables and fruits could ultimately reduce food wastes.

Figure 4. Classifications of household food wastes. Source: Parfitt et al. 2010	Figure 5. Food waste in million tonnes per year, categorized by food groups. Source: Parfitt et al. 2010

The purpose of packaging is to preserve and protect the food from outside contamination, with food waste considered to be decreased as a result of the longer shelf life from packaging. The major contributors to total MSW of packaging materials are paper (or paperboard) and plastic, at 84 and 28.9 million tons, respectively (Marsh and Bugusu, 2007). Prior to 2004, packaging process and materials were mainly petroleum based and performed at high temperatures; however, a materials breakthrough allowed packaging material to be made from a renewable resource derived from corn, polylactide (PLA) (Eilert, 2005).

Social

The increasing number of young people with minimal cooking skills, the decreasing available time to prepare meals due to employment and life-style patterns, and the baby-boom generation reaching retirement ages and being less willing to spend time cooking all contribute to the increase in processed food consumption (Eilert, 2005). Additionally, about 90% of US households have microwaves, providing further incentive, as it makes pre-cooked dinners easier and quicker to prepare. For example, in 1960, 80% of the poultry meat was still sold under the form of fresh, whole birds, whereas this has now been reduced to less than 5%. Since processed foods are quicker to prepare (Leroy and Degreef, 2015), tastier, and cheaper (Hawk, 2017), they are far more socially sustainable than fresh, unprocessed foods. The only caveat to this is the UPFs, as they are not a nutritious option (Drewnowski and Darmon, 2005).

The people with the most consistent tendency to convenience shop are those with values that motivate people to act independently and enhance their own personal interests. Other consumers likely to convenience shop are those with self-enhancement tendencies (personality traits like power and achievement seeking). This is because these people want to spend more time bettering themselves and furthering their careers than cooking (Botonaki and Mattas, 2010).In conducting interviews with 15 college students, the most important factor considered in food choices were the price of the product (Figure 6).

Figure 6. Most important factors considered in food purchases.		Figure 7. Mean prices of food products categorized by level of processing in 2010. Source: Hawk 2017

Economics

As shown from our survey (Figure 6), a big driver for purchasing certain foods is in price. The increasing prevalence of obesity correlates with the low cost of energy-dense foods, as consumers who value costs of food products tend to purchase high energy foods over low energy, high nutrient content foods such as vegetables (Drewnowski and Darmon, 2005). In studying food prices in a Washington County, Hawk (2017) analyzed prices from 379 food and beverage products. Categorizing the products into levels of processing, Hawk found an inverse relationship with processing and price such that as processing increases, the cost of the product decreases (Figure 7).

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Limitations

• Water use varies so widely when it comes to the different processing techniques (Hugas et al., 2002), and was excluded to ensure this study is complete and conclusive.
• The current research on the economic concerns surrounding food processing is lacking when it comes to the producer.
• GHG emissions from transportation were available, we chose to exclude them in this study due to the variability in GHG emissions based on the type of transportation (train, plane, boat, etc.) and distance between the farm, processing plant, and store.
• Our social study had some selection bias as we only interviewed our peers since we had limited time to get responses.

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Conclusions

There are certainly food processes that are beneficial to the nutritional content of a product, but some processes, such as UPFs, alter the nutritional content in a negative way. The increasing trend of UPF consumption correlates with decreased nutritional diversity, specifically in micronutrient content, and increased obesity trends in today’s society. Vegetable processing serves as a middle ground as the processing decreases the micronutrient content slightly, but the primary purpose of vegetable freezing and canning is to maintain the nutritional content of the foods for a longer time than the fresh products. Meat processing has no negative effects on the micronutrient or protein content of the food thanks to high pressure processing.

The environmental impact in terms of GHG emissions leaves a lot of room for improvement when it comes to agriculture. More research and additional policy implementations should be done here to cut down on the excess GHG emission produced when cultivating food off the farm. Processes should also continue to be implemented to increase environmental efficiency of processing, while simultaneously retaining nutritional content. There needs to be more research done to decrease energy in storing frozen UPFs, vegetables, and meats. This could be incredibly helpful because frozen goods last longer, but take more energy to conserve than fresh foods. The processing and packaging of products has decreased in the negative environmental impacts with improvements in non-thermal processing techniques and packaging material used, but these techniques and materials need to have more widespread use before a real improvement in GHG's or waste will be seen. This could be achieved by publicity surrounding packaging waste that will coax producers into using an environmentally friendly alternative. Additionally, an increase in incentives for recycling could reduce wastes greatly.

The social aspects can be improved by more widespread education of nutrition and the increasing trend of obesity. Developments in food processing to create healthier, convenient, and cheap food products could provide incentives for communities to make better food choices. In general, processing creates a more socially sustainable system because of the increased convenience and shelf-life of these products.

Processing is also very economically sustainable because it creates products that are much cheaper than their fresh counterparts. Additional research is needed to determine if there are any economic impacts of processing on producers and farmers though, because most of the research simply looks at how processing affects the consumer.

More research is needed directly comparing the effects of less food waste (due to the longer shelf-life) and more GHG emissions (due to the packaging) to come to a conclusive decision on the environmental effects of these processed foods. While environmental sustainability decreases, the economic and social sustainability increases with more processing; nutritional contents are only negatively impacted in some instances such as in UPF’s. This is not the case, however, with meats and vegetables.

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Citations

Acevedo, Miguel F, et al. Mar. 2018. “Food security and the environment: Interdisciplinary research to increase productivity while exercising conservation." Global Food Security 16: 127-132.

Agarwal, Sanjev, et al. Dec. 2015. “Association of lunch meat consumption with nutrient intake, diet quality and health risk factors in U.S. children and adults: NHANES 2007–2010.” Nutrition Journal, vol. 14, no. 1.

Batal, Malek, et al. Jul. 2017. “Quantifying associations of the dietary share of ultra-Processed foods with overall diet quality in First Nations peoples in the Canadian provinces of British Columbia, Alberta, Manitoba and Ontario.” Public Health Nutrition, vol. 21, no. 01, 103-113.