# Research and Development Status of Prepared Foods in China: A Review
## 3 The Classification of Prepared Foods  
Currently, there is no clear industry definition for the classification of prepared foods. However, there are many classifications of prepared foods in the prepared foods industry according to the different scenarios of consumption, processing methods, and preservation methods of prepared foods, which are classified in various ways [11]. According to different consumption scenarios, prepared foods can be divided into breakfast refreshments, dinner dishes, and snack foods [20]. Breakfast refreshments include bread, spaghetti, and jam. Dinner dishes are usually served as the main meal and need to be reheated or cooked. Snack foods are mainly small, packaged foods that are sterilized to achieve \"Commercial Sterility\" and can be consumed as snacks, such as beef jerky and dried apple slices. This classification can meet the needs of consumers for prepared foods in different scenarios in their lives [11]. When the different ways of cooking or reheating prepared foods are used as a classification principle, prepared foods can be divided into four types [21]. They are ready-to-heat foods, ready-to-cook foods, ready-to-eat foods, and ready-to-use foods. Ready-to-heat foods are foods that need to be heated so that they can be consumed, such as quick-frozen dumplings, quick-frozen glue pudding, and instant noodles. Ready-to-cook foods are foods that require simple cooking to be produced, such as marinated steak, mainly according to a consumer's preference to control the number and type of seasoning packets added to the simple cooking. Ready-to-eat foods are ready to eat out of the bag without processing or reheating and include dried bean curd, dried fish, and canned goods. Ready-to-use foods, also known as fast foods, mean that the net vegetables, net meat, and other auxiliary ingredients are divided into portions and finally combined to form fried vegetable buns, such as soup combinations and small fried vegetable buns. The classification of prepared foods based on cooking or reheating methods is a more accepted way of classification in the mainstream of the prepared foods industry today. It is effectively used in the processing and production of prepared foods. According to their different preservation conditions, prepared foods can be divided into frozen foods, refrigated foods, and normal temperature foods. Different refrigerated conditions have different effects on foods [22]. The storage temperature of frozen foods is below 0 \({}^{\circ}\)C, generally \(-18\)\({}^{\circ}\)C, and their representative products are mainly frozen pills, frozen meats, and frozen dumplings. Frozen foods are generally not sterilized, in a non \"Commercial Sterility\", and their shelf life in the frozen state can reach six months to a year, and some products last even longer. The preservation temperature of refrigerated foods is 0-5 \({}^{\circ}\)C, with their representative products net vegetables, marinated beef steaks, and marinated chicken steaks. Refrigerated foods are generally unsterilized, in a non \"Commercial Sterility\", and generally have a shelf life of 1 to 3 d in the refrigated state [23]. The storage temperature of normal-temperature foods is room temperature, and their representative products are small packages of marinated foods. Normal-temperature foods are sterilized, in a \"Commercial Sterility\", with a shelf life of six months to a year at room temperature [24]. This classification is often used in the preservation and transportation of prepared foods, which is essential to maintain flavour and food safety stability during the preservation and transportation process. Freeze-chilling involves freezing and frozen preservation, followed by thawing and chilled storage. It may have logistic benefits for food processors because it enables \"chilled\" products to reach more distant markets and facilitates bulk production of these foods.