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What are the limitations of the data set?
As very few foods have a constant composition, users should
be aware that the data does not represent absolute values. The
purpose of the database is to present a reflection of the usual
composition of foods as available and/or consumed, based on representative
samples. The New Zealand Food Composition Database 2006 contains
sample information, analytical sources and confidence limits for
data. Plant & Food Research is currently
working on the development of quality indicators for data in the
New Zealand Food Composition Database. All of this information
assists users to determine if the data is suitable for their intended
use.
Why don’t the polyunsaturated, monounsaturated
and saturated fatty acids add up to the total fat value?
The classes of fatty acids may not add up to the total lipid
value provided in the database because the fat value may include
some non-fatty acid material, such as glycerol, phosphate, sugar
or sterol. Lipid conversion factors for specific fats define the
amount of fatty acid (in grams) per gram of fat. The lipid conversion
factors used in the New Zealand Food Composition Database are
available on request from Plant & Food Research.
Does the New Zealand Food Composition
Database contain data on fortified foods in New Zealand?
Yes. For most fortified foods, the data represent
label information supplied by the manufacturers and compiled by
the New Zealand Manufactured Food Database, Nutrition Services,
Auckland Health Care. However, the database does contain some New
Zealand analytical values for fortified foods. Source codes are
assigned to data to differentiate manufacturer supplied data from
New Zealand analytical values.
How is dietary fibre analysed
for the NZFCD?
Dietary fibre has been measured at Plant & Food
Research using an
inhouse modification of the Englyst method (Englyst & Quigley
1992). Total and insoluble non-starch polysaccharides (NSP) are
measured, soluble NSP values are then calculated by difference.
This method allows the values of the components contributing to
dietary fibre to be added and over time will allow the total value
to be adjusted according to the definition of dietary fibre. The
Joint Australia New Zealand Food Standards Code prescribes the
Prosky method of analysis for the purpose of food labelling. For
this reason the dietary fibre values in the Nutrition
Information Panel Database have been sourced from
overseas datasets. The NZFCD is now using the Prosky method of
analysis.
Why is some of the data in the
NZFCD different to the information on product labels?
Some manufacturers choose to get products analysed for nutrient
composition, this approach usually produces the highest quality
data. A Nutrient Information Panel can also be created using a calculation
based on the composition of the ingredients and manufacturing processes.
The quality of this result will depend on the skill of the person
performing the calculation, the source of the data used in the calculation
(could be from New Zealand or overseas), and how representative
the data used in the calculation is of the actual ingredients in
the product. Differences between NZFCD values and product labels
can also reflect the fact that very few foods have a constant composition.
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Working
with us
The New Zealand
Institute for Plant & Food Research Limited and the Ministry of
Health jointly own and fund the New Zealand Food Composition Database.
Staff at Plant & Food Research manage and maintain the database.
