- Storage Life of Foods -

The home storage lives of various foods are shown in Figures 33, 34, 35, 36 and 37. These storage lives are only a rough approximation as the actual life of a particular food will depend on the initial quality, the type of processing, the storage temperature, the type of packaging, the moisture content of the food, the extent of contact with air and other factors.

There is no precise moment at which a food suddenly becomes undesirable. There is just a gradual deterioration; the colour may darken, the texture may soften or there may be loss of flavour or development of an off-flavour. There comes a time when there is a discernible change from the initial quality. The detection of this change will vary between individuals.

Changes that occur in a food when stored at temperatures higher than recommended are cumulative and cannot be reversed by returning the food to lower temperatures. The longer the storage time, the greater the deterioration in nutritional quality and palatability. In extreme cases the action of microbes can make the food unsafe to eat. Modern methods of food preservation, such as freezing, refrigeration and canning, considerably extend, above the normal, the time taken for a comparable loss of nutrients and eating quality.

Many food labels now include a date mark that gives an indication of the expected life of the food before a noticeable deterioration in quality occurs. The significance of the different forms of date marking is discussed on page 24. The 'use-by' or' minimum durable life' date is only applicable if the food is stored under the conditions specified on the label. If no special storage conditions are required normal cupboard storage should give the stated storage life.