Organic foods are foods produced by organic farming. While the standards differ worldwide, organic farming in general features cultural, biological, and mechanical practices that foster cycling of resources, promote ecological balance, and conserve biodiversity. Synthetic pesticides and chemical fertilizers are not allowed, although certain organically approved pesticides may be used under limited conditions. In general, organic foods are also not processed using irradiation, industrial solvents, or synthetic food additives. Currently, the European Union, the United States, Canada, Mexico, Japan and many other countries require producers to obtain special certification in order to market food as organic within their borders. In the context of these regulations, organic food is food produced in a way that complies with organic standards set by national governments and international organizations. Although the produce of kitchen gardens may be organic, selling food with the organic label is regulated by governmental food safety authorities, such as the US Department of Agriculture (USDA) or European Commission. While there may be some differences in the nutrient and anti-nutrient contents of organically and conventionally produced food, the variable nature of food production and handling makes it difficult to generalize results, and there is insufficient evidence to support claims that organic food is safer or healthier than conventional food. Claims that organic food tastes better are generally not supported by evidence.