Freezing and cooling by use of natural ice and snow is a method of food preservation traditionally available only in cold climates or in winter in temperate climates. Natural ice refrigeration on an industrial scale first developed in the late 19^th century, when refrigerated containers used in trains, ships, and then later trucks, greatly increased the production and consumption of red meat. Domestic freezing, chilling, and refrigeration on a mass scale is a phenomenon mostly of the second half of the 20^th century.

Today, much perishable food is solid frozen or chilled. Together with the growth of industrial refrigeration, domestic refrigerators began to be used in the USA, Australia, and New Zealand on the scale in the 1920s, and the Europe and Japan mostly since the 1950s. In Japan, for example, household processing refrigerators increased from 9 per cent in 1960 to 91 per cent in 1970, and 99 per cent in 2004. Supermarkets with freezers, chill cabinets, and domestic refrigerators are now commonable in the cities and towns of tropical countries; poorer rural communities still rely on drying, fermenting, salting, bottling, tinning, and other methods of food preservation, as well as their own gardens and farms. It is unlikely that refrigeration itself has any direct effect on the risk of cancer. Their effects are indirect.

• Refrigeration enables consumption of fresh perishable foods including seasonal vegetables and fruits all year round, as well as of fresh meat.
• Refrigeration reduces microbial and fungal contamination of perishable foods, notably cereals (grains) and pulses (legumes).
• Refrigeration reduces the need for and use of salting, smoking, curing, and pickling as methods of preserving vegetables, fruits and meat.

It can therefore be said that refrigeration (including freezing and chilling) indirectly influences risk of those cancers, the risk of which is affected by the above factors.

Evidence mounting to a judgement of ‘convincing’ or ‘probable’ for such factors relates to cancers of the mouth, pharynx, larynx, masopharynx, oesophagus, lung, stomach, pancreas, liver, and colon.

Reference: Reports from World Cancer Research Fund and American Institute for Cancer Research

  Mycotoxins are toxins produced by certain moulds or fungi. Although moulds that contaminate foods are usually destroyed by cooking temperatures, the toxins they produce may remain. Aflatoxins are one type of mycotoxin. All naturally occurring aflatoxins are classified as human carcinogens (group 1) by International Agency for Research on Cancer; other mycotoxins, such as fumonisins, are suspected carcinogens. It is common to find co-contamination by more than one species of mycotoxin-producing fungus. In Europe, the joint FAO/WHO expert committee on Food Additives and Contaminants recommends that aflatoxin concentrations in foods be kept as low as possible.

The main foods that may be contaminated by aflatoxins are all types of cereal (grain), including wheat, rice, maize (corn), barley, and oats; and pulses (legumes)-notably peanuts. Nuts and seeds may also be contaminated. Feedstuffs for farm animals may also be contaminated with aflatoxins, which can then be secreted in milk or accumulated in tissues.

Aflatoxins, which are produced by Aspergillus flavus and A. parasiticus, are most problematic in countries with hot, damp climates and poor storage facilities. Under these conditions, food may become contaminated with fungi and then accumulate such toxins. Such foods are marketed and consumed in the countries in which they are produced; they are also exported to neighboring countries and intercontinentally. Aflatoxin contamination is therefore an international issue.

Levels of aflatoxin contamination tend to be highest in countries where rates of liver cancer are high, such as some African countries and South-East Asia, including China. In general, rates are low in Europe, but relatively high rates of contamination have on occasion been found in the USA. Aflatoxin exposure levels are low in Europe and Australia, higher in the USA, and high in many low-income countries. This is particularly the case in tropical and subtropical regions where grains and nuts are stored for long periods under non-ideal conditions.

Rates are reduced by inspection, use of fungicides, and screening of imported foods. However, monitoring of levels of aflatoxin contamination in low-income countries is generally lacking.

Study on grapeseed extract, vitamin D, spices (turmeric and black pepper), resveratrol, selenium and chaparral revealed that they are natural cures for many cancers.

Grapeseed extract kills leukemia cancer cells.

Prof. Xianglin Shi group from the University of Kentucky, USA have found a natural substance in the grape fruit that's deadly to malignant leukemia cells. Grapeseed is a natural compound that appears to have relatively important properties. They found that within 24 hours, 76 percent of leukemia cells had died after being exposed to the extract. The scientists reported this study in the January 1, 2009, issue of Clinical Cancer Research, a journal of the American Association for Cancer Research.

Vitamin D inhibits the growth of breast cancer tumors.

Activated form of vitamin D causes "cellular differentiation" - essentially the opposite of cancer. Vitamin D might have a protective role against breast cancer. Both sunlight and dietary exposure to vitamin D have correlated with a reduced risk of breast cancer. Results of one small study suggested that body stores of vitamin D may be associated with survival chances in women with advanced breast cancer. Study by Prof. Barbara Mawer, Manchester Royal Infirmary in central England.

Spices reduced the growth of breast stem cells.

Compounds derived from the spices turmeric and pepper could help prevent breast cancer by limiting the growth of stem cells. Dr. Madhuri Kakarala group at the University of Michigan Comprehensive Cancer Center, USA have found that when the dietary compounds curcumin, which is derived from the Indian spice turmeric, and piperine, derived from black peppers, were applied to breast cells in culture, they decreased the number of stem cells while having no effect on normal differentiated cells.

Resveratrol prevents cancer.

Resveratrol is a naturally occurring phytoalexin produced by some higher plants in response to injury or fungal infection. Resveratrol is abundant in the skins of red grapes. Grape juice contains resveratrol, as does cranberry juice, but at levels that are ten times less than those in red. Resveratrol concentration in red wine varies greatly from one grape variety to another and from one region to another. When incubated with hepatoma cells, resveratrol induced Phase II detoxifying enzymes that detoxified and inhibited the proliferation of these cells. Grape skins, leaves, juice and red wine are all good sources of resveratrol. Resource by Richard Beliveau et al., in the book ‘Foods That Fight Cancer’.

Selenium helps prevent cancer.

Selenium is found in soil, and human consumption comes by eating plants that have absorbed the nutrient or fish or animals that have eaten plants as part of their diet. “The content of selenium in the food depends on the soil content of this trace element. Supplemental selenium could reduce cancer death rates by as much as 50%. 1,312 patients were given 200 mcg. of selenium daily. The patients receiving selenium had a rise of 67% in their blood selenium level. The patients receiving selenium had a 67% decrease in cancer of the prostate, a 58 percent decrease in colon or rectal cancer and a 45% decrease in lung cancer. This suggests that possibly up to 100,000 lives a year might be saved in the USA by the simple addition of selenium to the diet. -A Physicians Guide to Natural Health Products That Work  by James A. Howenstine, MD.

Chaparral treats cancer.

The plant is the creosote bush, or chaparral, also known as greasewood, and is a member of the oak family, has been used by Native Americans to treat a variety of illnesses, including cancer. Chaparral contains an ingredient called nor-dihihydroguairetic (NDGA), a potent antitumor agent. NDGA inhibits aerobic and anaerobic glycolysis (the energy-producing ability) of cancer cells. - Herbal Medicine, Healing and Cancer by Donald Yance and Arlene Valentine.