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.[34] 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.[34] 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.[33][35]
Saltiness is the taste of alkali metal ions such as sodium and potassium. It is found in almost every food in low to moderate proportions to enhance flavor, although to eat pure salt is regarded as highly unpleasant. There are many different types of salt, with each having a different degree of saltiness, including sea salt, fleur de sel, kosher salt, mined salt, and grey salt. Other than enhancing flavor, its significance is that the body needs and maintains a delicate electrolyte balance, which is the kidney's function. Salt may be iodized, meaning iodine has been added to it, a necessary nutrient that promotes thyroid function. Some canned foods, notably soups or packaged broths, tend to be high in salt as a means of preserving the food longer. Historically salt has long been used as a meat preservative as salt promotes water excretion. Similarly, dried foods also promote food safety.[76]

Vegetables are a second type of plant matter that is commonly eaten as food. These include root vegetables (potatoes and carrots), bulbs (onion family), leaf vegetables (spinach and lettuce), stem vegetables (bamboo shoots and asparagus), and inflorescence vegetables (globe artichokes and broccoli and other vegetables such as cabbage or cauliflower).[11]
Hybridization is different from grafting. Most of the world's vineyards are planted with European V. vinifera vines that have been grafted onto North American species' rootstock, a common practice due to their resistance to phylloxera, a root louse that eventually kills the vine. In the late 19th century, most of Europe's vineyards (excluding some of the driest in the south) were devastated by the infestation, leading to widespread vine deaths and eventual replanting. Grafting is done in every wine-producing region in the world except in Argentina, the Canary Islands and Chile—the only places not yet exposed to the insect.[71]
Organic food is food produced by methods that comply with the standards of organic farming. Standards vary worldwide, but organic farming in general features practices that strive to cycle resources, promote ecological balance, and conserve biodiversity. Organizations regulating organic products may restrict the use of certain pesticides and fertilizers in farming. In general, organic foods are also usually not processed using irradiation, industrial solvents or synthetic food additives.[45]
Anticarcinogens that may help prevent cancer can also be found in many food especially fruit and vegetables. Antioxidants are important groups of compounds that may help remove potentially harmful chemicals. It is however often difficult to identify the specific components in diet that serve to increase or decrease cancer risk since many food, such as beef steak and broccoli, contain low concentrations of both carcinogens and anticarcinogens.[144] There are many international certifications in cooking field, such as Monde Selection、A.A. Certification、iTQi. They use the high quality evaluation methods to make the food become more safe.
Live It! This phase is a lifelong approach to diet and health. In this phase, you learn more about food choices, portion sizes, menu planning, physical activity, exercise and sticking to healthy habits. You may continue to see a steady weight loss of 1 to 2 pounds (0.5 to 1 kilogram) a week until you reach your goal weight. This phase can also help you maintain your goal weight permanently.
Freezing food preserves it from the time it is prepared to the time it is eaten. Since early times, farmers, fishermen, and trappers have preserved grains and produce in unheated buildings during the winter season.[20] Freezing food slows down decomposition by turning residual moisture into ice, inhibiting the growth of most bacterial species. In the food commodity industry, there are two processes: mechanical and cryogenic (or flash freezing). The freezing kinetics is important to preserve the food quality and texture. Quicker freezing generates smaller ice crystals and maintains cellular structure. Cryogenic freezing is the quickest freezing technology available due to the ultra low liquid nitrogen temperature −196 °C (−320 °F).[21]
Fruits are the ripened ovaries of plants, including the seeds within. Many plants and animals have coevolved such that the fruits of the former are an attractive food source to the latter, because animals that eat the fruits may excrete the seeds some distance away. Fruits, therefore, make up a significant part of the diets of most cultures. Some botanical fruits, such as tomatoes, pumpkins, and eggplants, are eaten as vegetables.[10] (For more information, see list of fruits.)