It comes as no surprise that we are suffering from “information overload.” Most are also aware that the current information environment is a breeding ground for the propagation of myths. This situation certainly applies to food and health information, as addressed in the cover article “
Navigating For Health: Finding Accurate Information on the Internet” in this issue of
Food Insight.
Because food is so personal and can have a great impact on our health, consumers are seeking more information on nutrition, health and food safety. According to a Rodale Press survey, 43 percent of adults said that they follow health stories in all types of media “very closely.” (Princeton Research Associates for Rodale Press, 1999). Yet, when consumers hear about food myths that contradict scientific consensus, they are not sure what to do or who to believe. Indeed, 73 percent of consumers in the 2000 Food Marketing Institute’s Shopping for Health survey “strongly agree” or “mostly agree” that too much conflicting information exists about which foods are healthful and which ones are not.
New food myths regularly appear on top of the old food myths that continue to thrive. Food Insight asked renowned food science and nutrition researchers and academicians to address some of the common myths about food that they are frequently called on to debunk.
MYTH: Carbohydrates are the New Diet Disasters
FACT: “A frequent myth that I try to dispel is that carbohydrates are now ‘bad’ for you,” remarked Kristine Clark, Ph.D., director of sports nutrition at Pennsylvania State University. Dr. Clark provides nutrition counseling to people of all athletic levels, from Olympic team members to elderhostelers. Many of the athletes whom she counsels on their diets buy into the concept that carbohydrates make you fat, and Dr. Clark uses the following response to help put the total diet into perspective. “Rather than tell them, ‘no, that’s not true,’ I say, ‘you might be right if you overeat foods that are rich in carbohydrate. But, the same is also true if you overeat protein or fat.’” She then steers the conversation toward portion size. “My goal is to take the focus away from an individual nutrient and talk about ‘how much’ of something is appropriate for us to eat,” commented Dr. Clark. The tools and concepts used to explain portion size and balance in the diet are ones that have been around for years and are not the “latest and greatest” or a quick fix. The Food Guide Pyramid illustrates Dr. Clark’s points of balance and moderation. When speaking to competitive athletes she shows them that carbohydrates are in all five food groups, so avoiding this single nutrient will negatively impact energy levels. She uses a different approach when working with older adults. With that audience, she makes a case that carbohydrate-rich food, such as fruits and vegetables, is critical for important isoflavones, vitamins and minerals and has other benefits as well. Respected nutrition organizations, including The American Dietetic Association and the American Heart Association, recommend that at least 55 percent of a person’s diet consists of carbohydrate foods, including fruits, vegetables and grains.
MYTH: It Looks, Smells and Tastes Okay, So I Can Eat It and Not Get Sick
FACT: Most of us have witnessed this scenario before, or we may have even done it ourselves: a person takes food out of the refrigerator, visually inspects it, smells and often tastes it to see if it is okay to eat. “What many people look for is tangible evidence of spoilage, like mold, haze, skimming over or a shiny appearance, or they sniff it, looking for a detectable odor,” said Robert Gravani, Ph.D., professor of food science at Cornell University. “These signs are the result of spoilage bacteria growing in the food.”
But, there are two completely different “types” of bacteria. Spoilage bacteria can grow at temperatures below 40 degrees, such as in the refrigerator, and cause food to deteriorate and spoil, producing an unpleasant smell, taste or appearance. As an example, when orange juice is in the refrigerator for too long, it develops a “metallic” taste due to yeast growth. Some bacteria, such as Listeria monocytogenes, thrive at cold temperatures, and if present, will grow in the refrigerator and can cause illness.
The other type is pathogenic bacteria, which can grow rapidly in temperature ranges between 40 – 140 degrees and are the kind that cause foodborne illness. “The real concern is that the pathogenic organisms that cause foodborne illness, such as Salmonella species or E. coli O157:H7, do not present the same visual indicators as spoilage bacteria, but it doesn’t mean they aren’t lurking in your food,” continued Dr. Gravani. “Your senses may as well be out to lunch, because you can’t determine these organisms’ existence without a lab test.” The food safety adage of “when in doubt, throw it out” certainly applies in these cases, especially with leftovers that do not have “sell by” or “use by” dates or other means of determining when they are past their prime.
Dr. Gravani offers common sense tips to help consumers avoid foodborne illness: buy only what you can use in a reasonable amount of time, store food properly (keep hot foods hot and cold foods cold), and use the proper time frames for consuming food.
His advice on leftovers is cover them, date them, and rotate them out of the refrigerator. The Food Keeper, a publication co-sponsored by Cornell University, the United States Department of Agriculture’s Meat and Poultry Hotline and the Food Marketing Institute, includes a helpful chart on determining storage times for home-refrigerated foods and is available at www.fmi.org.
A word on freezing food: contrary to popular belief, freezing does not kill bacteria or viruses, although it will kill parasites. Keep in mind that the product that you put into the freezer is the same product when you take it out of the freezer. Freeze products for a future time, but note that proper food handling rules still apply.
MYTH: Food Irradiation Makes Food Radioactive
FACT: “Irradiation does not make food radioactive any more than an airport luggage X-ray scanner makes luggage radioactive,” noted Dr. Gravani. Food irradiation is a process in which food products are exposed to a controlled amount of radiant energy to kill harmful bacteria, for instance, E. coli O157:H7, Salmonella and Campylobacter. There are three approved energy sources for food irradiation: Electron beams (often used for ground beef), cobalt 60, and X-rays (not frequently used for food).
When food is irradiated, it is packed in containers and moved by conveyer belt into a protected room where it is exposed briefly to a source of ionizing energy, usually gamma rays. The food passes by the energy source at a set speed to control the amount of energy absorbed by the food, but the food never contacts the energy source. The energy penetrates the food and its packaging, breaking molecular bonds in the DNA of bacteria, pathogens and insects. The organisms die or they are unable to reproduce so their numbers are held down. The energy source is strong enough to destroy harmful bacteria, yet is neither strong enough to heat the food nor significantly change its chemical composition.
“Trace amounts of radioactivity are all around us, in our food, water and atmosphere,” observed Dr. Gravani. “Think of irradiation in terms of light passing through a window. Light is very short wavelengths of high energy that moves at a set speed, so it can penetrate a window but the window retains hardly any heat from the light.”
