The Food System

The food system is a network of farmers and related operations, including food processing, wholesale and distribution, retail, industry technology, and marketing. The milk industry, for example, includes everything from the farm that raises livestock, to the milking facility that extracts the product, to the processing company that pasteurizes milk and packages it into cartons, to the shipping company that delivers the product to stores, to the markets and groceries that stock and sell the product, to the advertising agency that touts the product to consumers. All of these components play a part in a very large system.

Two important aspects of a food system are preservation and processing. Each provides for or protects consumers in different ways. Food preservation includes the handling or treating of food to prevent or slow down spoilage. Food processing involves transforming raw ingredients into packaged food, from fresh-baked goods to frozen dinners. Although there are numerous benefits to both, preservation and processing also pose some concerns, in terms of both nutrition and sustainability.

Food Preservation

Food preservation protects consumers from harmful or toxic food by limiting the growth of bacteria within food. There are different ways to preserve food. Some are ancient methods that have been practiced for generations, such as curing, smoking, pickling, salting, fermenting, canning, and preserving fruit in the form of jam. Others include the use of modern techniques and technology, including drying, vacuum packing, pasteurization, and freezing and refrigeration. Preservation guards against foodborne illnesses, and also protects the flavor, color, moisture content, or nutritive value of food.  We’ll discuss a few of the more common forms of food preservation below, but be aware that there are many others.

Low-Temperature Storage

One of the most common ways food is preserved in the era of electricity is by storing it at low temperatures, either refrigeration (below 40°F/4ºC) or freezing (below 0ºF/-18ºC). The bacteria that cause food to spoil and the ones that can make us sick are unable to grow at these temperatures.  However, the bacteria are still there and will begin growing again if the food is put back into warmer temperatures, as happens if you leave it on the counter or if the power to your refrigerator fails.

High-Temperature Treatment

Low temperatures keep bacteria from growing, but high temperatures can actually kill bacteria. This is one reason why you cook many types of food before eating it (apart from enhancing the flavor).  This is also why you can boil contaminated water to make it drinkable.  There are several different forms of food preservation that use high temperatures to sterilize food.  We’ll discuss two: canning and Pasteurization.

Canning

In canning, foods are placed into jars or cans and heated to a temperature that destroys any bacteria, often by boiling.  The containers are also vacuum sealed to prevent other bacteria from entering after the container cools down.  Canning is an important part of the industrial food system, and many people also practice canning at home.

Pasteurization

Pasteurization is an industrial process used to eliminate bacteria in milk or juice.  This process was invented by the French chemist Louis Pasteur in 1862. Pasteurization involves exposing liquids to high temperatures for a very brief amount of time.  The short exposure keeps the liquid from cooking, reducing changes to taste or texture. The time and temperature used in Pasteurization varies depending on the product, but in the US, for milk, it’s around 158°F (70°C) for 15 seconds. This temperature greatly reduces the number of bacteria in milk but does not kill all of them, which is why milk in the US must remain refrigerated. Many other countries use ultra-high temperature Pasteurization for milk (140°C for 4 seconds), which kills all bacteria, meaning that unopened milk can last for months unrefrigerated.

Dehydration

Drying food is an effective method of food preservation, because bacteria need water in order to live, just like we do. This is possibly one of the earliest forms of food preservation. Sugar and salt may be used to accelerate the dehydration process, as both of these substances draw water out of bacterial cells at high concentrations. Think of a salty piece of beef jerky for an example of dehydration in action.

Fermentation

Fermentation is the process by which some types of bacteria or yeast break down carbohydrates to make ATP under anaerobic conditions. Some types of fermentation produce molecules that are toxic to bacteria. Different fermenting microbes produce different molecules through fermentation, including alcohol, carbon dioxide, and acids. The ethanol in wine, beer, and other alcoholic beverages and the carbon dioxide that causes bread to rise before baking are both products of fermentation. When fermentation is being used as food preservation, the fermentation product is usually lactic acid.  The acidity (low pH) of the fermented food inhibits growth of harmful bacteria.  You see this in sauerkraut, kimchi, and yogurt.

Food Irradiation: What You Need to Know

Food irradiation is a very modern form of preserving food that is not like any other. Food irradiation (the application of ionizing radiation to food) is a technology that improves the safety and extends the shelf life of foods by reducing or eliminating microorganisms and insects. Like pasteurizing milk and canning fruits and vegetables, irradiation can make food safer for the consumer. The Food and Drug Administration (FDA) is responsible for regulating the sources of radiation that are used to irradiate food. The FDA approves a source of radiation for use on foods only after it has determined that irradiating the food is safe.

Irradiation does not make foods radioactive, compromise nutritional quality, or noticeably change the taste, texture, or appearance of food. In fact, any changes made by irradiation are so minimal that it is not easy to tell if a food has been irradiated.

Why Irradiate Food?

Irradiation can serve many purposes.

• Prevention of Foodborne Illness – to effectively eliminate organisms that cause foodborne illness, such as Salmonella and E. coli.
• Preservation – to destroy or inactivate organisms that cause spoilage and decomposition and extend the shelf life of foods.
• Control of Insects – to destroy insects in or on tropical fruits imported into the United States. Irradiation also decreases the need for other pest-control practices that may harm the fruit.
• Delay of Sprouting and Ripening – to inhibit sprouting (e.g., potatoes) and delay ripening of fruit to increase longevity.
• Sterilization – irradiation can be used to sterilize foods, which can then be stored for years without refrigeration. Sterilized foods are useful in hospitals for patients with severely impaired immune systems, such as patients with AIDS or undergoing chemotherapy. Foods that are sterilized by irradiation are exposed to substantially higher levels of treatment than those approved for general use.

How Is Food Irradiated?

There are three sources of radiation approved for use on foods.

• Gamma rays are emitted from radioactive forms of the element cobalt (Cobalt 60) or of the element cesium (Cesium 137). Gamma radiation is used routinely to sterilize medical, dental, and household products and is also used for the radiation treatment of cancer.
• X-rays are produced by reflecting a high-energy stream of electrons off a target substance (usually one of the heavy metals) into food. X-rays are also widely used in medicine and industry to produce images of internal structures.
• Electron beam (or e-beam) is similar to X-rays and is a stream of high-energy electrons propelled from an electron accelerator into food.

Is Irradiated Food Safe to Eat?

The FDA has evaluated the safety of irradiated food for more than 30 years and has found the process to be safe. The World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC) and the U.S. Department of Agriculture (USDA) have also endorsed the safety of irradiated food.

The FDA has approved a variety of foods for irradiation in the United States including:

• Beef and Pork
• Crustaceans (e.g., lobster, shrimp, and crab)
• Fresh Fruits and Vegetables
• Lettuce and Spinach
• Poultry
• Seeds for Sprouting (e.g., for alfalfa sprouts)
• Shell Eggs
• Shellfish – Molluscan (e.g., oysters, clams, mussels, and scallops)
• Spices and Seasonings

How Will I Know if My Food Has Been Irradiated?

The FDA requires that irradiated foods bear the international symbol for irradiation. Look for the Radura symbol along with the statement “Treated with radiation” or “Treated by irradiation” on the food label. Bulk foods, such as fruits and vegetables, are required to be individually labeled or to have a label next to the sale container. The FDA does not require that individual ingredients in multi-ingredient foods (e.g., spices) be labeled. It is important to remember that irradiation is not a replacement for proper food handling practices by producers, processors, and consumers. Irradiated foods need to be stored, handled, and cooked in the same way as non-irradiated foods, because they could still become contaminated with disease-causing organisms after irradiation if the rules of basic food safety are not followed.^[1]