“Natural foods” are often assumed to be foods that are not processed, or do not contain any food additives, or do not contain particular additives such as hormones, antibiotics, sweeteners, food colors, or flavorings that were not originally in the food. In fact, many people (63%) when surveyed showed a preference for products labeled "natural" compared to the unmarked counterparts, based on the common belief (86% of polled consumers) that the term "natural" indicated that the food does not contain any artificial ingredients. The terms are variously used and misused on labels and in advertisements.
^ The sweetness multiplier "300 times" comes from subjective evaluations by a panel of test subjects Archived January 23, 2009, at the Wayback Machine tasting various dilutions compared to a standard dilution of sucrose. Sources referenced in this article say steviosides have up to 250 times the sweetness of sucrose, but others, including stevioside brands such as SweetLeaf, claim 300 times. 1/3 to 1/2 teaspoon (1.6–2.5 ml) of stevioside powder is claimed to have equivalent sweetening power to 1 cup (237 ml) of sugar.
Several studies published since 1990 indicate that cooking meat at high temperature creates heterocyclic amines (HCAs), which are thought to increase cancer risk in humans. Researchers at the National Cancer Institute found that human subjects who ate beef rare or medium-rare had less than one third the risk of stomach cancer than those who ate beef medium-well or well-done. While avoiding meat or eating meat raw may be the only ways to avoid HCAs in meat fully, the National Cancer Institute states that cooking meat below 212 °F (100 °C) creates "negligible amounts" of HCAs. Also, microwaving meat before cooking may reduce HCAs by 90% by reducing the time needed for the meat to be cooked at high heat. Nitrosamines are found in some food, and may be produced by some cooking processes from proteins or from nitrites used as food preservatives; cured meat such as bacon has been found to be carcinogenic, with links to colon cancer. Ascorbate, which is added to cured meat, however, reduces nitrosamine formation.
Food safety and food security are monitored by agencies like the International Association for Food Protection, World Resources Institute, World Food Programme, Food and Agriculture Organization, and International Food Information Council. They address issues such as sustainability, biological diversity, climate change, nutritional economics, population growth, water supply, and access to food.