Most of the world’s food supply undergoes some preservation and processing before being marketed. Preserving and processing foods provide many hidden benefits. Each protects consumers in different ways. Food preservation includes handling or treating food to prevent or slow down spoilage. Food processing involves transforming raw ingredients into packaged food, such as cutting whole carrots into baby carrots, canning fruits, and frozen meats. There are numerous benefits to preservation and processing; however, they also pose some concerns. They pose nutritional and sustainability problems. We will discuss this topic throughout the book.

Food Preservation

Food preservation protects consumers from harmful or toxic food, guards against foodborne illnesses, and also protects the flavor, color, moisture content, and nutritive value of food.  Fruits and vegetables have their highest vitamin content and flavor when they are fresh from the vine.  Freezing them helps to retain the qualities.

Foods may be preserved in a variety of ways. Some are ancient methods that have been practiced for generations, such as drying fruits, curing, smoking. or salting meats, pickling vegetables, and fermenting dairy products. Others include the use of modern techniques and technology, including drying, vacuum packing, pasteurization, and irradiation. Some people are skeptical about irradiation.

Food Irradiation 

Food irradiation is a preservation method that uses controlled energy to reduce or eliminate harmful microorganisms and insects. This process improves food safety and helps extend shelf life. Although it may be unfamiliar to some consumers, it functions much like pasteurization and canning in making foods safer to eat.

Major food and health organizations—including the U.S. Food and Drug Administration (FDA), World Health Organization (WHO), Centers for Disease Control and Prevention (CDC), and U.S. Department of Agriculture (USDA)—have determined that food irradiation is safe. Its use has grown over the past several decades and is widely accepted as an effective tool for food safety.

Irradiated foods are identified by the green Radura symbol on packaging, along with a statement such as “Treated with radiation” or “Treated by irradiation.” For bulk items like fruits and vegetables, labeling must appear on the product or nearby display. However, irradiated ingredients in multi-ingredient foods (such as spices) do not need to be individually labeled.

Irradiation is not a substitute for proper food handling throughout the food system. It also does not make food radioactive, significantly alter its nutritional value, or noticeably change its taste, texture, or appearance. As a result, consumers cannot detect whether a food has been irradiated.

We must follow basic food safety rules with irradiated foods, as they may still become contaminated with disease-causing microbes. ^[1] 

How Is Food Irradiated?

Three types of radiation are approved for use in food irradiation:

• Gamma rays: Produced from radioactive isotopes such as cobalt-60 or cesium-137. Gamma rays penetrate deeply into foods and are also used to sterilize medical equipment and treat cancer.
• X-rays: Generated when high-energy electrons strike a metal target. X-rays can penetrate food in much the same way as gamma rays, and they are widely used in medicine to create images of internal structures.
• Electron beam (e-beam): A stream of high-energy electrons produced by an electron accelerator. E-beam irradiation does not penetrate as deeply as gamma rays or X-rays and is typically used for thinner foods.

What foods are irradiated?

The FDA has approved several types of foods for irradiation in the United States, including:

• Beef, pork, and poultry
• Seafood (including crustaceans and molluscan shellfish)
• Fresh fruits and vegetables (including leafy greens such as lettuce and spinach)
• Seeds for sprouting (e.g., alfalfa sprouts)
• Shell eggs
• Spices and seasonings

Food Processing

Food processing includes the methods and techniques used to transform raw ingredients into packaged food. Workers in this industry use harvested crops or slaughtered livestock to produce products marketed to the public. There are different ways food can be processed, from a one-off product, such as a wedding cake, to a mass-produced product, such as a line of cupcakes packaged and sold in stores.

The Pros and Cons of Food Processing

Food processing offers several important benefits, including extending shelf life and making foods easier to store, transport, and distribute. In many cases, processing also improves food safety and convenience. However, there are some drawbacks to consider.

Certain processing methods can reduce the levels of heat-sensitive nutrients. For example, canning uses heat, which can lower the vitamin C content of fruits and vegetables. At the same time, some processing techniques can enhance nutrient availability or add nutrients through fortification.

Added ingredients are another consideration. Many processed foods contain added sugars, which can contribute to excess calorie intake if consumed in large amounts. Health organizations such as the American Heart Association recommend limiting added sugar to no more than 6 teaspoons per day for women and 9 teaspoons per day for men. For example, one 12-ounce can of regular soda contains about 9–10 teaspoons of added sugar, which exceeds or meets the daily recommended limit. ^[2]

Overall, the impact of processed foods on health depends on the type of processing and the overall dietary pattern.

Food Additives

If you examine the label on processed food, it is not unusual to see a long list of added ingredients. These natural or synthetic substances are food additives , and there are more than three hundred used during food processing today. The most popular additives are benzoates, nitrites, sulfites, and sorbates, which prevent molds and yeast from growing on food.^[3] Food additives are introduced in the processing stage for a variety of reasons. Some control acidity and alkalinity, while others enhance the color or flavor of food. Some additives stabilize food and keep it from breaking down, while others add body or texture. Table 1.5 lists some common food additives and their uses:

The Pros and Cons of Food Additives

The FDA works to protect the public from potentially dangerous additives. Passed in 1958, the Food Additives Amendment requires a manufacturer to demonstrate the safety of an additive before it can be approved. The Delaney Clause that was added to this legislation prohibits the approval of any additive found to cause cancer in animals or humans. However, most additives are considered to be “generally recognized as safe,” a status that is determined by the FDA and referred to as “GRAS.”

The Pros: Food additives are typically added during processing to improve product quality and consistency. Many additives also make items more “shelf stable,” meaning they will last a lot longer on store shelves and can generate more profit for store owners. Additives can also help prevent spoilage caused by temperature changes, damage during distribution, and other adverse conditions. In addition, food additives can protect consumers from exposure to rancid products and foodborne illnesses.

The Cons: Food additives aren’t always beneficial, however. Some substances have been associated with certain diseases if consumed in large amounts. For example, the FDA estimates that sulfites can cause allergic reactions in 1 percent of the general population and in 5 percent of asthmatics. Similarly, the additive monosodium glutamate, which is commonly known as MSG, may cause headaches, nausea, weakness, difficulty breathing, rapid heartbeat, and chest pain in some individuals.^[5]

Fermented Foods 

Fermentation helps preserve foods while also being a part of food processing. The most common fermented foods people eat today are dairy products such as cheese and yogurt. The fermentation process typically involves microorganisms converting the natural sugars in foods to alcohol or acid. Not all microbes are pathogenic and spoil foods. Many foods require the addition of bacteria, mold, or yeast to develop their typical characteristics. For example, all yogurts contain the bacteria Lactobacillus bulgaricus and Streptococcus thermophilus. (These are also known as probiotics or live active cultures.) The fungus Penicillium roqueforti gives blue cheese its characteristic color and flavor. And, of course, we all know that yeast is needed to make bread. The video below explains the roles these bacteria, fungi, and yeast play in fermentation.

Pre- and Probiotics:  What’s the Difference?

You’ve probably seen a lot in the media about probiotics and prebiotics—but what do they actually do?

Probiotics are live bacteria that can benefit your health, especially your digestive system. Even though bacteria often get a bad reputation, these are the “good” or “friendly” bacteria that help keep your gut healthy. A common type is lactobacilli, which are found in fermented foods like yogurt.

Prebiotics, on the other hand, are not bacteria. They are types of fiber that your body cannot digest. Instead, they act as food for the good bacteria already living in your large intestine, helping them grow and thrive.

Think of it this way:

• Probiotics = the good bacteria
• Prebiotics = the food that helps those bacteria grow

Research shows that probiotics can help reduce certain types of diarrhea (especially those caused by viruses) and may improve symptoms of lactose intolerance. Scientists are continuing to study these topics, and more health benefits may become clearer as research grows.

As interest in gut health increases, researchers are also working to better understand:

• Which specific strains of bacteria are most beneficial
• How much (dose) is needed for health effects
• Which foods or supplements are most effective

For now, including a variety of fiber-rich foods and fermented foods in your diet is a simple way to support a healthy gut.

attributions

This chapter is an adaptation of “Chapter 17. Food Safety” in Human Nutrition:2020 Edition by University of Hawai‘i at Mānoa Food Science and Human Nutrition Program licensed under a Creative Commons Attribution 4.0 International License.