Some wines are packaged in thick plastic bags within corrugated fiberboard boxes, and are called "box wines", or "cask wine". Tucked inside the package is a tap affixed to the bag in box, or bladder, that is later extended by the consumer for serving the contents. Box wine can stay acceptably fresh for up to a month after opening because the bladder collapses as wine is dispensed, limiting contact with air and, thus, slowing the rate of oxidation. In contrast, bottled wine oxidizes more rapidly after opening because of the increasing ratio of air to wine as the contents are dispensed; it can degrade considerably in a few days. Cans are one of the fastest-growing forms of alternative wine packaging on the market.
Food is traded and marketed on a global basis. The variety and availability of food is no longer restricted by the diversity of locally grown food or the limitations of the local growing season. Between 1961 and 1999, there was a 400% increase in worldwide food exports. Some countries are now economically dependent on food exports, which in some cases account for over 80% of all exports.
Most food has its origin in plants. Some food is obtained directly from plants; but even animals that are used as food sources are raised by feeding them food derived from plants. Cereal grain is a staple food that provides more food energy worldwide than any other type of crop. Corn (maize), wheat, and rice – in all of their varieties – account for 87% of all grain production worldwide. Most of the grain that is produced worldwide is fed to livestock.