Foodstuffs — Determination of water activity

Available format(s)

Hardcopy , PDF , PDF 3 Users , PDF 5 Users , PDF 9 Users

Language(s)

English, French

Published date

11-28-2017

Publisher

International Organization for Standardization

ISO 18787:2017 establishes basic principles and specifies requirements for the methods of determining water activity (a_w) of food products for human consumption and animal feed within a measurement range of 0 to 1.

The measurement principles are based on the dew-point measurement or on the determination of the change in electrical conductivity of an electrolyte or in the permittivity of a polymer.

The method does not apply to products stored below their freezing point (equivalent to the temperature at which ice crystals appear in the product), neither to products corresponding to a water-in-fat emulsion, nor to crystal products such as sugars, salt or minerals.

For products containing volatile compounds, such as alcohols, specific equipment adaptations may be necessary to apply the method.

The results of the interlaboratory studies that were carried out are given in Annex B.

Committee	ISO/TC 34
DevelopmentNote	Supersedes ISO/DIS 18787. (11/2017)
DocumentType	Standard
Pages	9
PublisherName	International Organization for Standardization
Status	Current
Supersedes	ISO 21807:2004

Standards	Relationship
NEN ISO 18787 : 2017	Identical
IS 17178:2019	Identical
NF ISO 18787 : 2017	Identical
BS ISO 18787:2017	Identical

ISO 5725-1:1994	Accuracy (trueness and precision) of measurement methods and results — Part 1: General principles and definitions
ISO 707:2008	Milk and milk products — Guidance on sampling
ISO 5725-2:1994	Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method
ISO 3696:1987	Water for analytical laboratory use — Specification and test methods
ISO 24333:2009	Cereals and cereal products — Sampling