Freezing is the technique of exposing foods to colder temperatures to preserve food. Pure water freezes at below 32 degrees Farenheit and 0 degrees Celsius. Foods high in water content will generally freeze below this temperature, but other ingredients, especially salt, will lower the temperature needed to freeze significantly.
When freezing foods for preservation, be sure to package in an airtight container or wrapping, such as a plastic freezer bag. Remove as much air as possible from packaging, otherwise your foods will be subject to "freezer burn" and absorbing flavors from other foods stored nearby. This can also be prevented by covering with a thin coating of water. When frozen the ice will protect your food like plastic.