IJCA - Volume 3 - Flipbook - Page 14
12
The International Journal of Conformity Assessment
Conformity Assessment of Sampling
for Food Safety
By J.Peter Krause, Sci. Advisor; and Udo Lampe, Managing Director, Analytica Alimentaria GmbH
DOI: 10.55459/IJCA/v3i1/PK.UL
-ABSTRACTDecisions on the food safety of generally large, mostly inhomogeneous batches of foods are based on
evaluated residue analyses of very small subsamples. The value of such a residue result primarily depends on
the representativeness of the primary sample, the laboratory subsample, and the reliability of the analytical
testing of the subsample. Many studies in the literature on sampling focus on sources of error, statistical
considerations, sampling guidelines, etc. However, little information is available on the conformity testing of
guidelines for sampling and the samplers themselves.
This study presents a conformity assessment guideline for sampling developed by Analytica Alimentaria.
The guideline aims to check either the conformity of a changed procedure or the work of a sampler. The test
consists of a quality criteria evaluation of the entire sampling process and the quantitative analysis of the
sample material. If the results are within an acceptable global estimation error, the test is considered to have
passed. Otherwise, a root cause analysis is conducted. The results have demonstrated considerable benefits
for robust and representative sampling in the field, reducing the probability of incorrect food safety decisions.
Keywords: Sampling crops, Pesticide residues, Uncertainty of measurements, Conformity test, Guideline
Introduction
The verification of the absence of harmful contaminations in foods,
such as pesticide residues, heavy metals, or microorganisms, play a
significant role in ensuring food safety. Typically, a large unit of food,
for instance a batch of packaged or bulk goods, or crops from a field of
several hectares, must be checked for food safety-relevant properties.
As a 100% inspection of the food is unrealistic for many reasons,
acceptance sampling is more widely used in practice.
There are many recommended guidelines for acceptance sampling that
include the required sample size [1], and acceptance benchmark for the
lot disposition [2, 3, 4 ]. In case of pesticides in fruits and vegetables,
for example, relevant regulations in the European Union include the
EC Directive 63/2002 (sampling for pesticide residues) [5] and the
EC Regulation 396/2005 (maximum residue levels) [6], respectively.
Sample size (mostly some kg) and sampling plan are defined for a
unit of food products. The food sample must be further reduced to
the laboratory size. The total reduction factor is often in the order of
10-12, starting from tons of foods in the original unit to 1 microgram
of laboratory sample for analysis. The reduction of the food sample
to the analysis sample can be validated quite well, as it is possible to
work with relatively homogeneously or randomly distributed analytes
in spiked food samples before analysis [7]. Sampling and chemicalmicrobiological laboratory analysis for safe foods are unthinkable
without a robust quality assurance system. The market therefore
demands appropriate accreditation from the laboratory provider to keep
the product owner capable of making decisions. ISO 17025 accreditation
requires conformity assessment procedures for every method used in
the laboratory, including the taking of a food sample.
