IJCA - Volume 3 - Flipbook - Page 58
56 The International Journal of Conformity Assessment
Figure 1: Food and non-food categories for AOAC and ISO method validation
CATEGORIES
Raw milk and
dairy products
Heat-processed
milk and dairy
products
Raw meat and
ready-to-cook
meat products
(except poultry)
Ready-to-eat,
ready-to-reheat
meat products
Raw poultry and
ready-to-cook
poultry products
Ready-to-eat,
ready-to-reheat
meat, poultry
products
Eggs and
egg products
(derivatives)
Raw and
ready-to-cook
昀椀sh and seafoods
(unprocessed)
Ready-to-eat,
ready-to-reheat
昀椀shery products
Fresh produce
and fruits
Processed fruits
and vegetables
Dried cereals,
fruits, nuts, seeds,
and vegetables
Infant formula and
infant cereals
Chocolate, bakery
products and
confectionary
Multi-component
foods or meal
components
Pet food and
animal feed
Environmental
samples (food or
feed production)
Primary
production
samples (PPS)
Distinction between scopes
• Broad range of foods: To make a claim that a method
The scope specifies the different categories, types,
and items for which a method can be applied. There
is a distinction between the scope of the method, the
scope of the validation of that method, and the scope
of the laboratory’s application of that method.
is validated for the scope: “a broad range of foods,” a
de昀椀ned number of (food) items must be tested from
at least 昀椀ve of these 15 (food) categories.
• Limited range of foods: To make a claim that a
method is validated for less than 昀椀ve food categories (called a “limited range of foods”), only selected
(food) categories from the 15 (food) categories are
included in the method validation (less than 昀椀ve).
• Other (non-foods): To claim validation for one or all
three of the non-food categories, additional items
from each of these categories would also need to
be validated.
• The scope of the method includes those matrices
and/or matrix categories that the method claims it
covers. It is often assumed that the scope of method
for a reference method applies to all matrices.
However, not all reference methods have been
validated for use with all matrices.
• The scope of validation for these methods is limited
to only those matrices or matrix categories that were
included in the method’s validation study.
• The scope of laboratory application would include
those matrices that are within the scope of
validation of the method and are routinely tested
within that laboratory.
Food and non-food categories
A method may claim to be valid for use with all
foods, as many reference methods do, but it is
not possible to validate a method for all foods. No
one can possibly include every existing food in a
validation study to be able to make such a claim.
Because of this, both AOAC INTERNATIONAL and
ISO have agreed to use the phrase “broad range
of foods” versus an “all foods” claim for method
validation studies. To support this terminology,
both organizations agreed on the classification of
“all foods” into fifteen (food) categories (plus three
‘Other’ non-food categories), as found in Annex A of
the standard and shown in Figure 1.
Veri昀椀cation is conducted in two stages:
1. Implementation veri昀椀cation is conducted 昀椀rst, to
demonstrate the user laboratory can conduct the
method correctly. This is conducted using one
(food) item.
For qualitative methods, this one (food) item
must be an item that was tested during the
method’s validation study, and the same sample size must be used as was tested during the
validation study.
For quantitative methods, this one (food) item
can be any (food) item from within the scope of
the validation of the method.
2. (Food) item veri昀椀cation demonstrates that the
user laboratory can conduct the method with the
types of (food) items that are routinely tested in
the user’s laboratory. The number of items required for testing will depend on the number of
categories for which the laboratory would routinely
use this method.
Because not many (food) items are tested during
veri昀椀cation, the standard prefers that the user