Under the Microscope: Organic farming was one of the fastest-growing segments of US agriculture during the 1990s. In the UK, organic farming is a billion pound industry and in many people's minds eating organic food is synonymous with healthy eating. But there is no body of scientific evidence to show that organic food is more nutritious or safer than food produced by conventional means.
Organic food must be produced without the assistance of synthetic fertilisers and pesticides, genetic engineering, growth hormones, irradiation and antibiotics. "Organic" does not mean "natural" and there is no legal definition as to what constitutes a "natural" food.
Organic farming is the oldest form of agriculture. Farmers before the end of the second World War had no option but to grow food without the assistance of the petroleum-based synthetic fertilisers and pesticides. Ironically, technologies developed during the war proved useful for agricultural production, eg ammonium nitrate used in munitions proved to be useful as a fertiliser and organophosphates used in nerve gas were put to use as insecticides.
During the 1960s and 1970s, as concerns rose over the state of the environment, some farmers switched back to organic farming again. Europe is now the biggest market for organic food in the world. There are more than 12,000 organic farmers in the US and the number is growing by 12 percent annually. A range of agricultural products can be produced organically including grains and vegetables, meat, dairy foods, eggs and processed food products.
The organic farming movement is a blend of science and ideology. It takes a principled stand against the dangers of agribusiness and junk food but it is sometimes hard to tease out its science from its ideology. Some of the founding fathers of organic farming were conventional scientists but others were decidedly odd, for example the Austrian philosopher and seer Rudolf Steiner (1861-1925), who advocated planting the soil with cow horns to capture the earth's rays.
Organic farming practices are quite different from conventional farming. Conventional farmers encourage their crops to grow with chemical fertilisers, protect crops from disease and pests with chemical insecticides and control weeds with synthetic herbicides. Organic farmers use natural fertiliser (manure) to grow crops, protect crops from pests and disease using natural methods such as insect predators, barriers and traps, and control weed growth by crop rotation, hand weeding, mechanical tillage and other methods. Overall yields of organically grown crops will typically be 50-80 percent of yields of conventionally grown crops.
Organically produced meat, dairy products and eggs come from animals fed organic feed. Organic livestock are kept in conditions that facilitate the natural habits of the animals (eg ruminants have access to pasture) and they are not given antibiotics, hormones or medication in the absence of illness. Diseases and parasites are largely controlled by preventive measures such as sanitary conditions and stress reduction.
Organic foods are up to 70 per cent more expensive for the consumer than conventionally produced food. There are several reasons for this - production costs are higher because of greater labour input; organic food supply is limited and demand for it is robust; marketing and distribution costs are high because of the relatively small volumes of organic food.
Are organic foods better than conventional foods? There is no body of scientific evidence to show that organic is safer than conventional food. Some studies have shown that people who eat conventionally grown food have more pesticide by-products in their urine than those who eat organic foods. But there is little or no evidence to show that pesticides in the very low amounts consumed by humans can cause cancer or any other ill effects. Also, if fruits and vegetables are properly washed, most of the chemical residues are removed.
It can also be argued that eating organic food carries its own health risks by increasing exposure to biological contamination. Food borne illness could be transmitted by manure pathogens, toxins from moulds and by toxic strains of the bacterium E Coli. However there is no scientific evidence that people are at significant risk from properly grown and handled organic food.
Many people claim that organic food tastes better than conventional food, but blind tests have shown that organic food cannot be distinguished by taste from conventional food when both foods are of equal freshness. Neither is there any body of research to show that organic food is more nutritious than conventional food.
One major criticism of organic farming is that it cannot produce enough food to feed everybody. World food production must be trebled over the next 50 years to feed an extra three billion people. It is therefore argued that all available technologies that increase efficiency in farming will be needed to increase the production of food.
There is a widespread contemporary fear that we are wrecking nature with science-based technology. In a Europe with plentiful food provided by modern agricultural methods we can afford to see great virtue in things not touched by human hand, to agonise over very small risks, and to lose our confidence in our ability to apply technology to positive ends.
Today we tend to worship nature and fear science. In ages past, the opposite view prevailed. Foods created by man such as wine and bread were symbols of cultured living - only barbarians ate wild plants. Reversion for a few years to pre-scientific agriculture would even out our thinking.
William Reville is associate professor of biochemistry and director of microscopy at UCC