Postharvest Handling and Preparation of Foods for Processing

Food processing is seasonal in nature, both in terms of demand for products and availability of raw materials. Most crops have well-established harvest times – for example, the sugar beet season lasts for only a few months of the year in the United Kingdom, so beet sugar production is confined to the autumn and winter, yet demand for sugar is continuous throughout the year. Even in the case of raw materials that are available throughout the year, such as milk, there are established peaks and troughs in volume of production, as well as variations in chemical composition. Availability may also be determined by less predictable factors, such as weather conditions, which may affect yields or limit harvesting. In other cases demand is seasonal, for example, ice cream or salads are in greater demand in the summer, whereas other foods are traditionally eaten in the winter months, or even at more specific times, such as Christmas or Easter. In an ideal world, food processors would like a continuous supply of raw materials, whose composition and quality are constant and whose prices are predictable. Of course this is usually impossible to achieve. In practice, processors contract ahead with growers to synchronize their needs with raw material production. The aim of this chapter is to consider the properties of raw materials in relation to food processing, and to summarize important aspects of handling, transport, storage, and preparation of rawmaterials prior to the range of processing operations described in the remainder of this book. The bulk of the chapter will deal with solid agricultural products including fruits, vegetables, cereals, and legumes, although many considerations can also be applied to animal-based materials such as meat, eggs, and milk.