Food Processing

Food processing has occurred since humanity began using fire and tools to cook meats, squeeze fruits for juice, or grind grains for flour.  We all use one or more processes in our kitchen to prepare meals. Food processing can be defined as the use of methods and techniques involving equipment, energy, and tools to transform agricultural products such as grains, meats, vegetables, fruits, and milk into food ingredients or processed food products.

Processed food is a related but slightly different term, where a food material has been changed in some way through a combination of ingredients together with processing steps to make the food safe to eat, shelf-stable for future use, convenient to use (e.g., microwaveable dinners), tasty/palatable, (e.g., a milk chocolate bar), and/or more nutritious (e.g., breakfast cereals fortified with vitamins).

All processed foods use food processing, but not all food processing leads to processed foods, for example, the process of washing apples before packaging for consumption.

While related, the terms food processing and processed food are not completely synonymous.   With advancements in science and technology and its application to produce food, has led to a considerable increase in the availability of processed foods. In the last few decades, there has been some criticism and confusion among consumers, health professionals, and others regarding the benefits and detriments associated with the consumption of processed foods.  It is important that communications on these topics should differentiate between food processing and processed food as described above, to help people make informed decisions about the food products they purchase and consume.  This tool kit provides helpful fact-based information to assist with communication on these topics.  

Food processing – A brief history
Traditional food processing methods that go back thousands of years include chopping, mixing & milling (converting grains into flour), and wet/dry heat-based processes, such as baking, cooking, roasting, frying, and smoking that inhibit or inactivate spoilage microorganisms, change the sensory attributes, and lengthen the time over which food can be consumed. Likewise, fermentation of fruits, grains, dairy, or meat by specific microorganisms that lead to the production of acids and/or alcohols have a similar preservative effect and also impact the taste. Food processes such as baking, drying, extraction (e.g., mashing of olives and decanting to make olive oil), brining— (addition of salt or sugar for extending shelf-life of meat or seafood), or combinations of any of these methods developed over time by various cultures has enabled the shift from subsistence to sustainable food production. These food processing methods have been utilized for centuries and continue to advance to meet the needs of the growing population. 

Recent food processing technologies are often extensions of these original food processing methods and have helped in creating food products such as canned vegetables, juices, and jellies and jams in the 19th century. The use of pasteurization (controlled time and temperature process to destroy illness-causing micro-organisms and spoilage enzymes) helps extend the shelf-life of products such as milk and beer. The advent of industrial-scale refrigeration in the late 1800's enabled the chilling or freezing of food products and led to the development of refrigerated/frozen food products in concert with the advent of in-home refrigerator/freezers in the early 1900’s. Quick freezing, invented by Birdseye in the 1920’s, enabled the delivery of foods that when thawed and cooked were almost like the fresh version and maintained most of the sensory and nutrient properties.

During the 20th century, many newly discovered ingredients were used (food additives) to make foods more convenient to use and/or to enhance their appearance and/or taste. The advent of prepared dinners, high in salt and modified starches, in the 1950’s, the rapid expansion of fast serve food, and widespread availability of candies and beverages high in sugar in combination with synthetic food dyes are examples of convenience, indulgence, and enjoyment foods. Consumer demands for natural ingredients led to the development of natural additives, such as anti-microbial preservatives (e.g., nisin) and antioxidants (e.g., rosemary extract). Advances in food processing technologies such as canning, freezing, and aseptic processing in the 20th century led to the year-round availability of seasonal fruits and vegetables without the addition of food additives, while maintaining much of the original nutritional properties of the food and reducing food waste.

Current state of food processing
In the 21st century, advances in food processing have also transformed food formulation, such as replacing sugar with naturally sourced non-caloric sweeteners (e.g., stevia derivatives), which have helped reduce sugar consumption by 28 lbs. per person since 1999 in the U.S. The demand for natural and easily identifiable ingredients in food products has led to the development of vitamins and colorants from natural sources to replace the synthetic versions, for example. Another example is the creation of gluten-free products for a subset of consumers who may be sensitive/intolerant to gluten or have celiac disease. The continued advancement of food science, engineering, and packaging has led to nutritious and healthy food and beverage products in the marketplace. However, many processed food products that are unhealthful (high in saturated fat, sugar, and/or salt), convenient, and often inexpensive continue to be in the marketplace and have led to consumer confusion and misperceptions about food processing. Many technical advancements and product designs are being pursued to address the unhealthful food trends of the past century, while still maintaining and improving food safety and year-round availability of nutritious products. 

New Food Processing Technologies
Research on food and food processing continues to expand as people are increasingly interested in leveraging food to benefit their health and the environment. Some of the new technologies being researched focus on reducing and reusing food waste. With the world population expected to increase to 9 billion by 2050, technology to re-capture and re-use such waste will become more critical as the limitations of growing food becomes greater due to various causes, such as limited availability of arable land and water and climate changes. Linked to this is new technology development around sustainable food packaging (i.e., bio-degradable), as plastic waste has become a major issue globally. The globalization of food poses additional challenges, such as food safety for the food system. Artificial intelligence could be used to collect data and manage food processes to further enhance food safety and quality and optimize distribution networks to address this challenge. Research to maintain or enhance the nutritional value of food and its effects on human health, as well as how the food is grown and distributed will drive new processing technologies through the remainder of the 21st century.

What is processed food?
The combination of food ingredients (food formulation) and use of processing step(s) to design a food product with particularly desired attributes (formulated food) is termed as processed food).

What is food processing?
Food processing can be defined as the use of equipment, energy, and tools to safely and efficiently transform food ingredients like grains, meats, vegetables, or fruits with minimal waste into more value-added ingredients or in combination to obtain more convenient processed food products for sale. Examples of value-added ingredients include flour, milk powder, liquid eggs, frozen vegetables, frozen chicken breast, and cooking oil. Examples of processed food products include cheese dips, ready to eat cereals, potato chips, salad mixes, packaged lunchmeats, and baked muffins. We might consider ingredients like flour or cooking oil as a processed product since they are sold in stores, but we do not generally eat flour or consume cooking oil without further preparation, such as making bread from flour. Food processing is used to make value-added ingredients and processed food products for business-to-business sales, food service establishments, and sales in retail outlets, such as supermarkets and convenience stores, and for preparation and consumption at home. Most of the food in our food supply undergoes some form of processing, however, not all food is considered as processed food, for example, carrots that are washed, cleaned, and refrigerated.

What is the need for processing food?
Since before recorded history, mankind has been processing food to preserve it for later consumption (e.g., drying meat), make it more convenient to use or handle (e.g., grinding wheat into flour), and/or make seasonal produce available year-round (e.g., drying fruits or canning vegetables). Every day, most people employ simple (such as cooking eggs and toasting bread) or complex (e.g., preparing a multi-step, yeast-leavened sweet bread) processes to prepare food. Food processing makes it easier to provide shelf-stable, convenient to use, and tasty/palatable food products. For example, the invention 150 years ago of quick-cooking (via moist heat) and rolling of whole grains like oats enabled consumers to prepare a cooked oatmeal breakfast in 10% of the time it otherwise required (from 50 to 5 minutes), without changing the nutritional characteristics or adding other food ingredients. Even today, healthy whole grains are prepared using the same techniques with more automated and large-scale equipment. Food processing also enables the delivery of a consistent food ingredient for repeated use. For example, imagine the challenge that consumers or food service establishments would face if the time required to cook oatmeal varied between 3 and 15 minutes vs. 5 minutes, which they expect. Food processing leads to a much more consistent end use as well as a continuous supply of ingredients and food products.

Are there different types of food processes?
There are a wide variety of food processes across a range involving one or a combination of steps (unit operations) that can be done from the scale of a home kitchen to large production factories employing thousands of people. Simple steps like washing, chopping, cooking, or mixing of spices together to make unique flavor blends involve only one or two steps (unit operations), while more modern technologies like ultra-high heat treated (UHT), aseptically filled milk, or modified atmosphere packaging involve numerous steps with tremendous complexities and require scientific understanding to function successfully. Often, numerous food processing steps are used in concert with a variety of ingredients to create food products that are safe to consume even 12-18 months later, while still retaining the taste, texture, nutritional value, and appearance, thus becoming a processed food. Processed foods are often easier to store and transport, including exporting to other countries.

Are there misconceptions about food processing?
Food has a significant impact on a person’s health. It is a common bond that connects people. Most of us have a fundamental understanding of food processing primarily through our experiences at home (e.g., washing, cooking, grilling, and freezing), but are unaware or know very little about the complexities associated with industrial food processing to make food products that are purchased frequently at grocery stores. Hence for many, it is a mystery. Ingredients such as flour, roasted coffee, and cooking oil, and food products like jams, canned vegetables, and ready-to-eat shelf-stable dinners all undergo food processing, but only some are generally considered processed foods and these differences are unknown/unclear to some consumers. Many consumers who roast coffee beans at home would not consider roasted coffee beans as processed food, even though they undergo several processing steps.

Several organizations have created definitions for food processing and/or processed foods. For example, the International Food Information Council (IFIC) has created a set of scaled definitions for processed foods — from Minimally processed to Highly Processed, that provides some help in defining the degree to which a food has been processed.

While useful in some respect, these tools provide limited guidance about the nutrition value of the food. The challenge with such tools is that they fail to fully incorporate the breadth and complexity of food — their inherent nutritional variations and the variety of processes used to make the food product. So far, creating a universal definition that incorporates all of these factors is difficult as demonstrated by the ongoing revisions of the definition established by the United Nations Food and Agriculture Organization.

Are there any benefits of processing foods?
There are many benefits associated with processing foods which are discussed below.

Food safety
The safety of food is of paramount concern to everyone who purchases food products at a retail store or food service establishment. Food safety challenges occur in developed and developing countries. The drive to simplify ingredient labels, increased availability of conveniently packaged healthful foods like salad mixes and refrigerated pre-cut fruits and vegetables, increased consumption of food away from home and/or home delivery, as well as the globalization of food sourcing has created complexities, which could potentially increase the incidents of food-borne illness above the infrequent good manufacturing lapses like improper sanitation or incorrect processing conditions. New measures, such as regulatory requirements related to food traceability, recall authority, prevention of bioterrorism via food (e.g., U.S. Food Safety Modernization Act in USA, 2011), and advances in processing technologies continue to be implemented to improve food safety. Hidden from view to most consumers are technologies for rapid testing for microbial or chemical contamination, tracing of a food ingredient back to its source location, and enhanced temperature control of refrigerated or frozen food from point of production to the retail or food service establishment, where the consumer purchases the product. The food industry plays a major role in ensuring that our food is safe by implementing complex food safety systems, policies and regulations, and employee training. Despite the headlines on food recalls that we occasionally see and the increased complexities of the food supply chain, the safety of the food we consume continues to improve. Food processing systems in the 21st century and the associated safety and quality management tools enable continued delivery of more nutritious and safe food than any time in human history. A key component of food safety is having well-trained food industry and regulatory personnel with multiple checks and balances in place to manage the highly complex food processing systems, distribution networks, and food service and retail establishments responsible for delivering food to people. Finally, continued consumer education regarding food safety at home is critical.

Food preservation & year-round food supply
Most fruits and vegetables become available during certain seasons of the year (e.g., apples). How is it that we enjoy these fruits and vegetables all-year-round? One way is by sourcing from another country during the off-season (e.g., Chile or New Zealand). However, this creates major logistical complications to maintain the quality of the product for sale to consumers. Another option is to store the fruits and vegetables in refrigerated, controlled atmosphere environments and apply an edible, protective coat to preserve the product for off-seasonal use. The use of technologies, such as aseptic and ultra-high temperature food processing allows some food products to be stored unrefrigerated for a longer period of time, for example, high-protein nutrition shake with a shelf-life of 12 months, for older adults.

Convenience and availability
Advances in food processing have resulted in the development and widespread availability of convenient food products that require minimal preparation/cooking and ready-to-eat (RTE) food products, some of which are also healthful. For example, whole grain pasta made by cooking, extruding, and drying grain flour, is a shelf-stable product that requires minimal preparation time.

Another example of advances in food processing is the increasing availability of many regionally grown food products, such as pineapple grown in Hawaii, the Philippines, or Thailand in convenient single-serve plastic packages. Similarly, modern food processing and distribution systems enable the availability of fresh or frozen seafood from virtually anywhere in the world to land-locked markets like the Midwest in the United States.

Food product cost
Advances in food processing to deliver benefits such as food safety, preservation, shelf-life extension, and/or convenience is often associated with increased costs. However, large-scale processing technologies enable production of cost-effective products for consumers to purchase at grocery stores rather than make it at home from raw ingredients. Consumer purchasing and consumption decisions are influenced by many factors, including taste, cost, perceived quality, nutritional health, and/or environmental considerations. Food processing is used to achieve one or more of these factors.

Healthy options
Food processing has helped deliver healthy food options (e.g., plant-based foods, plant-based protein, low-fat meat and dairy products, foods high in whole grains, frozen fruits and vegetables, canned vegetables with low sodium, and canned fruits in water or in 100% fruits juice with no added sugar) to assist consumers in following a healthy dietary pattern(s). While some food processing steps (e.g., cooking) can lead to nutrient loss (e.g., vitamin C), they also sometimes can increase the availability of nutrients, for example, lycopene in tomatoes or fiber in grains.

Does food processing make the food unhealthy?
Not necessarily. Food processing is a tool used to make food safe, nutritious, palatable, convenient, shelf-stable, affordable, and accessible. Like any tool, it can be used properly or improperly, and it is important that its use is regulated and controlled by well-trained people. Some food processing steps like cooking can reduce available nutrients, but the step(s) could also eliminate potential illness causing microorganisms. In some cases, processing can increase the bioavailability of nutrients, for example, lycopene in tomatoes, or decrease negative components like lectins in beans. Food processing can sometimes lead to potentially harmful byproducts, such as acrylamide in fried foods.

Does food processing change the food?
Processing of food can change all types of attributes within the food. For example, the blending of nutrients into foods (e.g., vitamin D in milk) could improve the nutrient status in populations where the intake of a nutrient is low/deficient. Extraction of olive oil from olives enables cooking with a healthy oil source as part of the Mediterranean diet. The process of cooking makes food safe to consume by eliminating pathogenic or spoilage causing organisms that could make us sick or make the food inedible, change the texture and flavor of food (e.g., fresh vs. cooked vegetables), and/or degrade certain essential nutrients, such as vitamin C. Another example is milling, which transforms grains into different forms such as flour. Generally speaking, processing makes food easier to consume or use than in the original state and enables its safe use over a longer period of time.

Are new food processing technologies potentially harmful?
It is unlikely that the consumption of food produced using a new processing technology would be harmful to a consumer. Most countries require a thorough evaluation of a new technology before its implementation in food manufacturing. For example, consumers were concerned about microwave cooking technology, where the use of radio waves to cook food was thought to make the food unsafe. However, the technology was thoroughly tested by regulatory agencies and manufacturers before it was applied broadly in homes and food production. Now, many people around the world use microwave to cook food.

How does new technology support food processing?
Historically, the application of technology has brought many beneficial capabilities to the processing of food. Further, understanding the relationship between food nutrients/components and their impact on human health has helped develop technologies to create food products that benefit health. For example, gluten-free options are available for a subset of individuals who are intolerant/insensitive to gluten or who have celiac disease.

Are organic foods processed differently?
Organic foods/ingredients are processed in the same manner as their non-organic counterparts. However, ingredients used in organic foods are grown as per a countries’ requirements, which vary from country to country. Organic farms cannot use synthetic fertilizers and pesticides for multiple growing seasons before the product can be considered organic. An organic farm cannot use synthetic fertilizer. Except for a few, most synthetic pesticides are not allowed for organic agriculture. Naturally derived pesticides may be used if they are not indicated as prohibited in the National Organic Program’s “National List of Allowed and Prohibited Substances.” Further, organic raw ingredients/foods are required to be stored separately from the non-organic ingredients/foods. Beyond the farm, organic products must be segregated from non-organic products at each food processing step throughout the food production. Organic food products can be produced on the same processing system as non-organic, however, there are additional requirements for cleaning the processing equipment to avoid co-mingling with non-organic foods/ingredients. For example, organic whole grain pasta undergoes the same processing steps (cooking, extruding, and drying of grain flour) as its non-organic counterpart but the grain is grown in an organic farm, stored separately, and processed on equipment's which are cleaned thoroughly or on equipment's that are only used for organic products, to avoid co-mingling with non-organic ingredients.

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Food processing has occurred since humanity began using fire, tools to cook meats, squeeze fruits for juice, or grind grains for flour. All processed foods use food processing, but not all food processing leads to processed foods.

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