The home storage
lives of various foods are shown in Figures 33,
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
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.
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.