Food Composition 289individual data items, and easy sorting and manipula-
tion of data for use in a wide range of calculations.
However, the ease of accessing data in an electronic
or a computerized database is dependent on the data-
base access software and not only on the way in which
data are stored. The development of relational data-
bases has led to the opening up of possibilities to link
different databases in regions and countries with each
other. This has led to the identifi cation of new chal-
lenges such as food identifi cation, compatibility of
data, data interchange and data quality.
11.7 Converting foods to nutrients
Entering data
Before the computer age, the conversion of food con-
sumption into nutrient intake had to be done manu-
ally, which was a laborious and time-consuming task.
Later, much of the work, especially for larger surveys,
was done on mainframe computers, and has since
passed on to microcomputers, because of their ready
accessibility and ease of use. Data on food and nutri-
ent intakes were often subsequently transferred to a
mainframe computer, where they were combined
with other survey data for further analysis. Today,
there is little that cannot be done on a microcom-
puter, including data manipulation such as sorting
and calculations.
Before proceeding to calculate nutrient intake from
data on food consumption, it is necessary to ensure
that mistakes that have crept into the data set during
acquiring, coding, merging, transcription, and storage
are reduced to an acceptable level. Regardless of the
method used for the collection of data on food con-
sumption, consideration should be given to how the
data will be entered into the computer. Suitable forms
should be designed for the collection of data. These
can be on paper or in a personal computer-based
program that can save time and eliminate errors asso-
ciated with the transcription of data from paper to
the computer. The use of carefully prepared forms,
with information to guide those collecting the data,
can reduce the chance of error during the collection
of data and, if a separate process, during entry into
the computer. The collection and entry of data are
subject to human and computer error; therefore, pro-
cedures must be developed to ensure that the quality
of data is as high as possible. Editing and error-
checking routines should be incorporated in the data
entry process and subsets of data entered into the
computer should be compared with the original
written records. Where mistakes are found, the extent
of the error should be determined, because it could
involve data for the previous (or next) subject or day,
or those previously (or subsequently) entered by the
operator involved. In addition to such checks, fre-
quency distributions of all amounts of food and food
codes should be carried out. The Food Surveys
Research Group of the Agricultural Research Service
of the USDA has developed an automated method for
collecting and processing dietary intake data. The
three computer systems, Automated Multiple Pass
Method (AMPM), Post-Interview Processing System
(PIPS) and Survey Net collect, process, code, review,
and analyze data for nutrient intakes. The system has
been used for the National Health and Nutrition
Examination survey since 2002.Converting data in food intake to
nutrient intake
A crucial aspect of food composition research is the
transmission of information from those working in
food composition and analysis to those working
in food monitoring, to scientists trying to improve the
food supply, to workers in epidemiological, training
and nutrition programs, and to regulators. Yet there
is little discussion in the scientifi c literature of the
issues relating directly to the compilation of food
composition databases, which are the primary means
of transmission of food composition data to most
professionals in the fi eld. If good food statistics are
available in a country, as well as access to food intake
and food composition databases, estimates of a higher
quality can be made regarding the nutrient intake of
the individual or population as a whole. However, few
data on food composition exist for the 790 million
people in developing countries who are chronically
undernourished and where malnutrition in the form
of defi ciencies of iron, iodine, and vitamin A is rife.11.8 Perspectives on the future
No universal food database system has been devel-
oped that fulfi lls all of the needs of compilers and
users of food databases, despite the fact that it would
represent the primary scientifi c resource from which
all other nutritional studies fl ow. However, recent